From 50a57836cc507b3a50c418147b7bdccbbccd7cef Mon Sep 17 00:00:00 2001
From: Dj <djedward@users.noreply.github.com>
Date: Mon, 3 Aug 2026 12:51:21 -0700
Subject: [PATCH] Fix serialization test bugs and enable Go 1.27 compat

---
 .github/workflows/lint.yml             |  8 +--
 .github/workflows/tests.yml            |  4 +-
 cfn/event_test.go                      |  6 +-
 cfn/response.go                        |  4 +-
 cfn/wrap_test.go                       |  4 +-
 cmd/build-lambda-zip/main.go           |  5 +-
 cmd/build-lambda-zip/main_test.go      | 10 +--
 events/activemq_test.go                |  2 +-
 events/alb_test.go                     |  8 +--
 events/apigw_test.go                   | 47 +++++++-------
 events/appsync_test.go                 | 14 ++---
 events/autoscaling_test.go             |  2 +-
 events/chime_bot_test.go               |  2 +-
 events/clientvpn_test.go               |  6 +-
 events/cloudwatch_events_test.go       |  2 +-
 events/codebuild_test.go               |  4 +-
 events/codedeploy_test.go              |  4 +-
 events/codepipeline_cloudwatch_test.go |  4 +-
 events/codepipeline_job_test.go        |  6 +-
 events/codepipeline_test.go            |  6 +-
 events/cognito_test.go                 | 42 ++++++-------
 events/config_test.go                  |  6 +-
 events/connect_test.go                 |  2 +-
 events/dynamodb_test.go                |  4 +-
 events/ecr_image_action_test.go        |  2 +-
 events/ecr_scan_test.go                |  2 +-
 events/ecs_container_instance_test.go  |  2 +-
 events/example_s3_test.go              |  4 +-
 events/firehose_test.go                |  2 +-
 events/iot_1_click_test.go             |  2 +-
 events/iot_button_test.go              |  2 +-
 events/iot_preprovision_hook_test.go   | 10 +--
 events/iot_test.go                     | 10 +--
 events/kafka_test.go                   |  2 +-
 events/kinesis_analytics_test.go       |  2 +-
 events/kinesis_test.go                 |  4 +-
 events/lambda_function_urls_test.go    |  9 +--
 events/lex_test.go                     |  4 +-
 events/rabbitmq_test.go                |  2 +-
 events/s3_object_lambda_test.go        |  2 +-
 events/s3_test.go                      |  2 +-
 events/ses_test.go                     |  2 +-
 events/sns_test.go                     |  2 +-
 events/sqs_test.go                     |  2 +-
 events/test/assert.go                  |  8 +--
 events/test/assert_test.go             | 85 ++++++++++++++++++++++++++
 events/test/jsonsyntax.go              | 13 ++--
 events/test/jsonsyntax_test.go         | 84 +++++++++++++++++++++++++
 events/test/readjson.go                |  6 +-
 events/test/readjson_test.go           | 38 ++++++++++++
 events/test/testdata/event.json        |  1 +
 lambda/errors.go                       |  4 +-
 lambda/extensions_api_client.go        |  9 ++-
 lambda/handler.go                      |  3 +-
 lambda/handler_test.go                 |  9 ++-
 lambda/invoke_loop_gte_go122_test.go   | 24 +++++++-
 lambda/invoke_loop_test.go             |  6 +-
 lambda/runtime_api_client.go           |  3 +-
 lambda/runtime_api_client_test.go      |  5 +-
 lambda/sigterm_test.go                 | 49 ++++++++++++---
 lambdaurl/http_handler_test.go         |  7 +--
 61 files changed, 445 insertions(+), 180 deletions(-)
 create mode 100644 events/test/assert_test.go
 create mode 100644 events/test/jsonsyntax_test.go
 create mode 100644 events/test/readjson_test.go
 create mode 100644 events/test/testdata/event.json

diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index fb54d23d..501977b1 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -16,11 +16,11 @@ jobs:
     name: run golangci-golint on the project
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
-      - uses: actions/setup-go@4a3601121dd01d1626a1e23e37211e3254c1c06c # v6
+      - uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7
+      - uses: actions/setup-go@b7ad1dad31e06c5925ef5d2fc7ad053ef454303e # v7
         with:
           go-version: 'stable'
       - name: golangci-golint
-        uses: golangci/golangci-lint-action@1e7e51e771db61008b38414a730f564565cf7c20 # v9
+        uses: golangci/golangci-lint-action@ba0d7d2ec06a0ea1cb5fa41b2e4a3ab91d21278a # v9
         with:
-          version: v2.9.0
+          version: v2.13.1
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 47c3a7bd..c94e320a 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -11,6 +11,7 @@ jobs:
       fail-fast: false
       matrix:
         go:
+          - "1.27"
           - "1.26"
           - "1.25"
           - "1.24"
@@ -22,9 +23,6 @@ jobs:
           - "1.18"
           - "1.17"
           - "1.16"
-          - "1.15"
-          - "1.14"
-          - "1.13"
 
     steps:
       - name: Set up Go ${{ matrix.go }}
diff --git a/cfn/event_test.go b/cfn/event_test.go
index 9d22ad01..73080d0b 100644
--- a/cfn/event_test.go
+++ b/cfn/event_test.go
@@ -4,7 +4,7 @@ package cfn
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -13,7 +13,7 @@ import (
 func TestCloudFormationEventMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cloudformation-event.json")
+	inputJSON, err := os.ReadFile("./testdata/cloudformation-event.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -34,5 +34,5 @@ func TestCloudFormationEventMarshaling(t *testing.T) {
 }
 
 func TestCloudFormationMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, Event{})
+	test.TestMalformedJson(t, &Event{})
 }
diff --git a/cfn/response.go b/cfn/response.go
index 375ddcb8..5b786f5f 100644
--- a/cfn/response.go
+++ b/cfn/response.go
@@ -6,7 +6,7 @@ import (
 	"bytes"
 	"encoding/json"
 	"fmt"
-	"io/ioutil" //nolint: staticcheck
+	"io"
 	"log"
 	"net/http"
 )
@@ -67,7 +67,7 @@ func (r *Response) sendWith(client httpClient) error {
 		return err
 	}
 
-	body, err = ioutil.ReadAll(res.Body)
+	body, err = io.ReadAll(res.Body)
 	if err != nil {
 		return err
 	}
diff --git a/cfn/wrap_test.go b/cfn/wrap_test.go
index 7eadbd1a..f2a664b3 100644
--- a/cfn/wrap_test.go
+++ b/cfn/wrap_test.go
@@ -8,7 +8,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil" //nolint: staticcheck
+	"io"
 	"net/http"
 	"testing"
 
@@ -209,7 +209,7 @@ func TestWrappedSendFailure(t *testing.T) {
 func extractResponseBody(t *testing.T, req *http.Request) Response {
 	assert.NotContains(t, req.Header, "Content-Type")
 
-	body, err := ioutil.ReadAll(req.Body)
+	body, err := io.ReadAll(req.Body)
 	assert.NoError(t, err)
 	var response Response
 	err = json.Unmarshal(body, &response)
diff --git a/cmd/build-lambda-zip/main.go b/cmd/build-lambda-zip/main.go
index 80a45334..799ce5ef 100644
--- a/cmd/build-lambda-zip/main.go
+++ b/cmd/build-lambda-zip/main.go
@@ -6,7 +6,6 @@ import (
 	"archive/zip"
 	"flag"
 	"fmt"
-	"io/ioutil" //nolint: staticcheck
 	"log"
 	"os"
 	"path/filepath"
@@ -82,7 +81,7 @@ func compressExeAndArgs(outZipPath string, exePath string, args []string) error
 
 	zipWriter := zip.NewWriter(zipFile)
 	defer zipWriter.Close()
-	data, err := ioutil.ReadFile(exePath)
+	data, err := os.ReadFile(exePath)
 	if err != nil {
 		return err
 	}
@@ -97,7 +96,7 @@ func compressExeAndArgs(outZipPath string, exePath string, args []string) error
 		if err != nil {
 			return err
 		}
-		data, err := ioutil.ReadFile(arg)
+		data, err := os.ReadFile(arg)
 		if err != nil {
 			return err
 		}
diff --git a/cmd/build-lambda-zip/main_test.go b/cmd/build-lambda-zip/main_test.go
index 6def4c49..ae2c823f 100644
--- a/cmd/build-lambda-zip/main_test.go
+++ b/cmd/build-lambda-zip/main_test.go
@@ -5,7 +5,7 @@ package main
 import (
 	"archive/zip"
 	"fmt"
-	"io/ioutil" //nolint: staticcheck
+	"io"
 	"os"
 	"os/exec"
 	"path"
@@ -34,7 +34,7 @@ func TestSizes(t *testing.T) {
 	}
 	testDir, err := os.Getwd()
 	require.NoError(t, err)
-	tempDir, err := ioutil.TempDir("/tmp", "build-lambda-zip")
+	tempDir, err := os.MkdirTemp("/tmp", "build-lambda-zip")
 	require.NoError(t, err)
 	for _, test := range cases {
 		require.NoError(t, os.Chdir(testDir))
@@ -66,7 +66,7 @@ func TestSizes(t *testing.T) {
 }
 
 func TestCompressExeAndArgs(t *testing.T) {
-	tempDir, err := ioutil.TempDir("/tmp", "build-lambda-zip")
+	tempDir, err := os.MkdirTemp("/tmp", "build-lambda-zip")
 	require.NoError(t, err)
 	defer os.RemoveAll(tempDir)
 
@@ -117,7 +117,7 @@ func TestCompressExeAndArgs(t *testing.T) {
 		link, err := bootstrap.Open()
 		require.NoError(t, err)
 		defer link.Close()
-		linkTarget, err := ioutil.ReadAll(link)
+		linkTarget, err := io.ReadAll(link)
 		require.NoError(t, err)
 		assert.Equal(t, filepath.Base(filePaths[0]), string(linkTarget))
 	})
@@ -148,7 +148,7 @@ func TestCompressExeAndArgs(t *testing.T) {
 				f, err := zf.Open()
 				require.NoError(t, err)
 				defer f.Close()
-				content, err := ioutil.ReadAll(f)
+				content, err := io.ReadAll(f)
 				require.NoError(t, err)
 				assert.Equal(t, fmt.Sprintf("Hello file %d!", expectedIndex), string(content), "in file: %s", zf.Name)
 				expectedIndex++
diff --git a/events/activemq_test.go b/events/activemq_test.go
index 7b967893..5f04b597 100644
--- a/events/activemq_test.go
+++ b/events/activemq_test.go
@@ -43,5 +43,5 @@ func TestActiveMQEventMarshaling(t *testing.T) {
 }
 
 func TestActiveMQMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ActiveMQEvent{})
+	test.TestMalformedJson(t, &ActiveMQEvent{})
 }
diff --git a/events/alb_test.go b/events/alb_test.go
index 56d5b963..84757a47 100644
--- a/events/alb_test.go
+++ b/events/alb_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -16,7 +16,7 @@ func TestALBTargetRequestMarshaling(t *testing.T) {
 
 	for _, filename := range inputFiles {
 		// read json from file
-		inputJSON, err := ioutil.ReadFile(filename)
+		inputJSON, err := os.ReadFile(filename)
 		if err != nil {
 			t.Errorf("could not open test file. details: %v", err)
 		}
@@ -37,13 +37,13 @@ func TestALBTargetRequestMarshaling(t *testing.T) {
 }
 
 func TestALBTargetRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ALBTargetGroupRequest{})
+	test.TestMalformedJson(t, &ALBTargetGroupRequest{})
 }
 
 func TestALBTargetResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/alb-lambda-target-response.json")
+	inputJSON, err := os.ReadFile("./testdata/alb-lambda-target-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
diff --git a/events/apigw_test.go b/events/apigw_test.go
index 651718ab..9db86d78 100644
--- a/events/apigw_test.go
+++ b/events/apigw_test.go
@@ -5,8 +5,9 @@ package events
 import (
 	"encoding/json"
 	"errors"
-	"io/ioutil" //nolint: staticcheck
+	"io"
 	"net/http"
+	"os"
 	"strings"
 	"testing"
 
@@ -18,7 +19,7 @@ import (
 func TestApiGatewayRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -57,13 +58,13 @@ func TestApiGatewayRequestMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayProxyRequest{})
+	test.TestMalformedJson(t, &APIGatewayProxyRequest{})
 }
 
 func TestApiGatewayResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-response.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -84,7 +85,7 @@ func TestApiGatewayResponseMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayProxyResponse{})
+	test.TestMalformedJson(t, &APIGatewayProxyResponse{})
 }
 
 func TestAPIGatewayProxyStreamingResponseMarshaling(t *testing.T) {
@@ -122,7 +123,7 @@ func TestAPIGatewayProxyStreamingResponseMarshaling(t *testing.T) {
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
-			response, err := ioutil.ReadAll(test.response)
+			response, err := io.ReadAll(test.response)
 			require.NoError(t, err)
 			sep := "\x00\x00\x00\x00\x00\x00\x00\x00"
 			responseParts := strings.Split(string(response), sep)
@@ -164,7 +165,7 @@ func TestAPIGatewayProxyStreamingResponsePropogatesInnerClose(t *testing.T) {
 func TestApiGatewayCustomAuthorizerRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-custom-auth-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-custom-auth-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -187,7 +188,7 @@ func TestApiGatewayCustomAuthorizerRequestMarshaling(t *testing.T) {
 func TestApiGatewayCustomAuthorizerRequestTypeRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-custom-auth-request-type-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-custom-auth-request-type-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -208,17 +209,17 @@ func TestApiGatewayCustomAuthorizerRequestTypeRequestMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayCustomAuthorizerRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayCustomAuthorizerRequest{})
+	test.TestMalformedJson(t, &APIGatewayCustomAuthorizerRequest{})
 }
 
 func TestApiGatewayCustomAuthorizerRequestTypeRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayCustomAuthorizerRequestTypeRequest{})
+	test.TestMalformedJson(t, &APIGatewayCustomAuthorizerRequestTypeRequest{})
 }
 
 func TestApiGatewayWebsocketRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-websocket-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-websocket-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -241,7 +242,7 @@ func TestApiGatewayWebsocketRequestMarshaling(t *testing.T) {
 func TestApiGatewayWebsocketRequestSendMessageMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-websocket-request-send-message.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-websocket-request-send-message.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -264,7 +265,7 @@ func TestApiGatewayWebsocketRequestSendMessageMarshaling(t *testing.T) {
 func TestApiGatewayWebsocketRequestDisconnectMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-websocket-request-disconnect.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-websocket-request-disconnect.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -285,13 +286,13 @@ func TestApiGatewayWebsocketRequestDisconnectMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayWebsocketRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayWebsocketProxyRequest{})
+	test.TestMalformedJson(t, &APIGatewayWebsocketProxyRequest{})
 }
 
 func TestApiGatewayCustomAuthorizerResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-custom-auth-response.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-custom-auth-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -373,13 +374,13 @@ func TestAPIGatewayV2CustomAuthorizerSimpleResponseMarshalling(t *testing.T) {
 }
 
 func TestApiGatewayCustomAuthorizerResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, APIGatewayCustomAuthorizerResponse{})
+	test.TestMalformedJson(t, &APIGatewayCustomAuthorizerResponse{})
 }
 
 func TestApiGatewayRestApiOpenApiRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-restapi-openapi-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-restapi-openapi-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -408,7 +409,7 @@ func TestApiGatewayRestApiOpenApiRequestMarshaling(t *testing.T) {
 func TestApiGatewayV2HTTPRequestJWTAuthorizerMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-request-jwt-authorizer.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-request-jwt-authorizer.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -443,7 +444,7 @@ func TestApiGatewayV2HTTPRequestJWTAuthorizerMarshaling(t *testing.T) {
 func TestApiGatewayV2HTTPRequestLambdaAuthorizerMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-request-lambda-authorizer.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-request-lambda-authorizer.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -478,7 +479,7 @@ func TestApiGatewayV2HTTPRequestLambdaAuthorizerMarshaling(t *testing.T) {
 func TestApiGatewayV2HTTPRequestIAMMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-request-iam.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-request-iam.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -537,7 +538,7 @@ func TestApiGatewayV2HTTPRequestIAMMarshaling(t *testing.T) {
 func TestApiGatewayV2HTTPRequestNoAuthorizerMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-request-no-authorizer.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-request-no-authorizer.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -570,7 +571,7 @@ func TestApiGatewayV2HTTPRequestNoAuthorizerMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayV2CustomAuthorizerV1RequestMarshaling(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-custom-authorizer-v1-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-custom-authorizer-v1-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -591,7 +592,7 @@ func TestApiGatewayV2CustomAuthorizerV1RequestMarshaling(t *testing.T) {
 }
 
 func TestApiGatewayV2CustomAuthorizerV2RequestMarshaling(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/apigw-v2-custom-authorizer-v2-request.json")
+	inputJSON, err := os.ReadFile("./testdata/apigw-v2-custom-authorizer-v2-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
diff --git a/events/appsync_test.go b/events/appsync_test.go
index 2e179261..647d2335 100644
--- a/events/appsync_test.go
+++ b/events/appsync_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -10,7 +10,7 @@ import (
 )
 
 func TestAppSyncIdentity_IAM(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/appsync-identity-iam.json")
+	inputJSON, err := os.ReadFile("./testdata/appsync-identity-iam.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -29,7 +29,7 @@ func TestAppSyncIdentity_IAM(t *testing.T) {
 }
 
 func TestAppSyncIdentity_Cognito(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/appsync-identity-cognito.json")
+	inputJSON, err := os.ReadFile("./testdata/appsync-identity-cognito.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -48,7 +48,7 @@ func TestAppSyncIdentity_Cognito(t *testing.T) {
 }
 
 func TestAppSyncLambdaAuthorizerRequestMarshalling(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/appsync-lambda-auth-request.json")
+	inputJSON, err := os.ReadFile("./testdata/appsync-lambda-auth-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -67,11 +67,11 @@ func TestAppSyncLambdaAuthorizerRequestMarshalling(t *testing.T) {
 }
 
 func TestAppSyncLambdaAuthorizerRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, AppSyncLambdaAuthorizerRequest{})
+	test.TestMalformedJson(t, &AppSyncLambdaAuthorizerRequest{})
 }
 
 func TestAppSyncLambdaAuthorizerResponseMarshalling(t *testing.T) {
-	inputJSON, err := ioutil.ReadFile("./testdata/appsync-lambda-auth-response.json")
+	inputJSON, err := os.ReadFile("./testdata/appsync-lambda-auth-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -90,5 +90,5 @@ func TestAppSyncLambdaAuthorizerResponseMarshalling(t *testing.T) {
 }
 
 func TestAppSyncLambdaAuthorizerResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, AppSyncLambdaAuthorizerResponse{})
+	test.TestMalformedJson(t, &AppSyncLambdaAuthorizerResponse{})
 }
diff --git a/events/autoscaling_test.go b/events/autoscaling_test.go
index a41541d8..d5712037 100644
--- a/events/autoscaling_test.go
+++ b/events/autoscaling_test.go
@@ -37,5 +37,5 @@ func TestAutoScalingEventMarshaling(t *testing.T) {
 }
 
 func TestAutoScalingMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, AutoScalingEvent{})
+	test.TestMalformedJson(t, &AutoScalingEvent{})
 }
diff --git a/events/chime_bot_test.go b/events/chime_bot_test.go
index 3caba67e..e898ee32 100644
--- a/events/chime_bot_test.go
+++ b/events/chime_bot_test.go
@@ -135,5 +135,5 @@ func TestChimeBotEventMarshaling(t *testing.T) {
 }
 
 func TestChimeBotMarshalingMalformedJSON(t *testing.T) {
-	test.TestMalformedJson(t, ChimeBotEvent{})
+	test.TestMalformedJson(t, &ChimeBotEvent{})
 }
diff --git a/events/clientvpn_test.go b/events/clientvpn_test.go
index aae58d59..c46abc7a 100644
--- a/events/clientvpn_test.go
+++ b/events/clientvpn_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -11,7 +11,7 @@ import (
 
 func TestClientVPNConnectionHandlerRequestMarshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/clientvpn-connectionhandler-request.json")
+	inputJSON, err := os.ReadFile("./testdata/clientvpn-connectionhandler-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -32,5 +32,5 @@ func TestClientVPNConnectionHandlerRequestMarshaling(t *testing.T) {
 }
 
 func TestClientVPNConnectionHandlerRequestMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ClientVPNConnectionHandlerRequest{})
+	test.TestMalformedJson(t, &ClientVPNConnectionHandlerRequest{})
 }
diff --git a/events/cloudwatch_events_test.go b/events/cloudwatch_events_test.go
index 3f49caba..c364bb86 100644
--- a/events/cloudwatch_events_test.go
+++ b/events/cloudwatch_events_test.go
@@ -32,5 +32,5 @@ func TestCloudwatchScheduledEventIdempotency(t *testing.T) {
 }
 
 func TestCloudwatchScheduledEventRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CloudWatchEvent{})
+	test.TestMalformedJson(t, &CloudWatchEvent{})
 }
diff --git a/events/codebuild_test.go b/events/codebuild_test.go
index d0e1b693..6d25c1fb 100644
--- a/events/codebuild_test.go
+++ b/events/codebuild_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 	"time"
 
@@ -301,7 +301,7 @@ func TestUnmarshalCodeBuildEvent(t *testing.T) {
 	}
 
 	for _, testcase := range tests {
-		data, err := ioutil.ReadFile(testcase.input)
+		data, err := os.ReadFile(testcase.input)
 		require.NoError(t, err)
 
 		var actual CodeBuildEvent
diff --git a/events/codedeploy_test.go b/events/codedeploy_test.go
index c363f77d..5cd1cb59 100644
--- a/events/codedeploy_test.go
+++ b/events/codedeploy_test.go
@@ -3,7 +3,7 @@ package events
 import (
 	"encoding/json"
 	"github.com/stretchr/testify/require"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 	"time"
 )
@@ -67,7 +67,7 @@ func TestUnmarshalCodeDeployEvent(t *testing.T) {
 	}
 
 	for _, testcase := range tests {
-		data, err := ioutil.ReadFile(testcase.input)
+		data, err := os.ReadFile(testcase.input)
 		require.NoError(t, err)
 
 		var actual CodeDeployEvent
diff --git a/events/codepipeline_cloudwatch_test.go b/events/codepipeline_cloudwatch_test.go
index 13321980..7cf85ed5 100644
--- a/events/codepipeline_cloudwatch_test.go
+++ b/events/codepipeline_cloudwatch_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 	"time"
 
@@ -89,7 +89,7 @@ func TestUnmarshalCodePipelineEvent(t *testing.T) {
 	}
 
 	for _, testcase := range tests {
-		data, err := ioutil.ReadFile(testcase.input)
+		data, err := os.ReadFile(testcase.input)
 		require.NoError(t, err)
 
 		var actual CodePipelineCloudWatchEvent
diff --git a/events/codepipeline_job_test.go b/events/codepipeline_job_test.go
index c78bfa0d..cfca0a12 100644
--- a/events/codepipeline_job_test.go
+++ b/events/codepipeline_job_test.go
@@ -3,7 +3,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -13,7 +13,7 @@ import (
 func TestCodePipeLineJobEventMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/codepipeline-job-event.json")
+	inputJSON, err := os.ReadFile("./testdata/codepipeline-job-event.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -34,5 +34,5 @@ func TestCodePipeLineJobEventMarshaling(t *testing.T) {
 }
 
 func TestCodePipelineJobEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CodePipelineJobEvent{})
+	test.TestMalformedJson(t, &CodePipelineJobEvent{})
 }
diff --git a/events/codepipeline_test.go b/events/codepipeline_test.go
index cb7e0e6a..36c312cf 100644
--- a/events/codepipeline_test.go
+++ b/events/codepipeline_test.go
@@ -3,7 +3,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -13,7 +13,7 @@ import (
 func TestCodePipeLineEventMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/codepipeline-job-event.json")
+	inputJSON, err := os.ReadFile("./testdata/codepipeline-job-event.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -34,5 +34,5 @@ func TestCodePipeLineEventMarshaling(t *testing.T) {
 }
 
 func TestCodePipelineEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CodePipelineEvent{})
+	test.TestMalformedJson(t, &CodePipelineEvent{})
 }
diff --git a/events/cognito_test.go b/events/cognito_test.go
index 7a18e601..823e1bdb 100644
--- a/events/cognito_test.go
+++ b/events/cognito_test.go
@@ -3,7 +3,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -13,7 +13,7 @@ import (
 func TestCognitoEventMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -34,13 +34,13 @@ func TestCognitoEventMarshaling(t *testing.T) {
 }
 
 func TestCognitoMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEvent{})
+	test.TestMalformedJson(t, &CognitoEvent{})
 }
 
 func TestCognitoEventUserPoolsPreSignupMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-presignup.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-presignup.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -61,13 +61,13 @@ func TestCognitoEventUserPoolsPreSignupMarshaling(t *testing.T) {
 }
 
 func TestCognitoUserPoolsPreSignupMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsPreSignup{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsPreSignup{})
 }
 
 func TestCognitoEventUserPoolsPreAuthenticationMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-preauthentication.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-preauthentication.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -88,13 +88,13 @@ func TestCognitoEventUserPoolsPreAuthenticationMarshaling(t *testing.T) {
 }
 
 func TestCognitoUserPoolsPreAuthenticationMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsPreAuthentication{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsPreAuthentication{})
 }
 
 func TestCognitoEventUserPoolsPostConfirmationMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-postconfirmation.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-postconfirmation.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -115,12 +115,12 @@ func TestCognitoEventUserPoolsPostConfirmationMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsPreTokenGenMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsPreTokenGen{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsPreTokenGen{})
 }
 
 func TestCognitoEventUserPoolsPreTokenGenMarshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-pretokengen.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-pretokengen.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -142,7 +142,7 @@ func TestCognitoEventUserPoolsPreTokenGenMarshaling(t *testing.T) {
 
 func TestCognitoEventUserPoolsPreTokenGenV2Marshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-pretokengen-v2.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-pretokengen-v2.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -164,7 +164,7 @@ func TestCognitoEventUserPoolsPreTokenGenV2Marshaling(t *testing.T) {
 
 func TestCognitoEventUserPoolsPreTokenGenV2_0Marshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-pretokengen-v2_0.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-pretokengen-v2_0.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -190,7 +190,7 @@ func TestCognitoEventUserPoolsDefineAuthChallengeMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsDefineAuthChallengeMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsDefineAuthChallenge{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsDefineAuthChallenge{})
 }
 
 func TestCognitoEventUserPoolsCreateAuthChallengeMarshaling(t *testing.T) {
@@ -199,7 +199,7 @@ func TestCognitoEventUserPoolsCreateAuthChallengeMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsCreateAuthChallengeMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsCreateAuthChallenge{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsCreateAuthChallenge{})
 }
 
 func TestCognitoEventUserPoolsVerifyAuthChallengeMarshaling(t *testing.T) {
@@ -208,13 +208,13 @@ func TestCognitoEventUserPoolsVerifyAuthChallengeMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsVerifyAuthChallengeMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsVerifyAuthChallenge{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsVerifyAuthChallenge{})
 }
 
 func TestCognitoEventUserPoolsPostAuthenticationMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-postauthentication.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-postauthentication.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -235,12 +235,12 @@ func TestCognitoEventUserPoolsPostAuthenticationMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsMigrateUserMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsMigrateUser{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsMigrateUser{})
 }
 
 func TestCognitoEventUserPoolsMigrateUserMarshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-migrateuser.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-migrateuser.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -261,7 +261,7 @@ func TestCognitoEventUserPoolsMigrateUserMarshaling(t *testing.T) {
 
 func TestCognitoEventUserPoolsCustomMessageMarshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/cognito-event-userpools-custommessage.json")
+	inputJSON, err := os.ReadFile("./testdata/cognito-event-userpools-custommessage.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -282,7 +282,7 @@ func TestCognitoEventUserPoolsCustomMessageMarshaling(t *testing.T) {
 }
 
 func TestCognitoUserPoolsCustomMessageMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsCustomMessage{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsCustomMessage{})
 }
 
 func TestCognitoEventUserPoolsInboundFederationOIDCMarshaling(t *testing.T) {
@@ -296,5 +296,5 @@ func TestCognitoEventUserPoolsInboundFederationSAMLMarshaling(t *testing.T) {
 }
 
 func TestCognitoEventUserPoolsInboundFederationMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, CognitoEventUserPoolsInboundFederation{})
+	test.TestMalformedJson(t, &CognitoEventUserPoolsInboundFederation{})
 }
diff --git a/events/config_test.go b/events/config_test.go
index 57b31123..9a9b593a 100644
--- a/events/config_test.go
+++ b/events/config_test.go
@@ -3,7 +3,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -12,7 +12,7 @@ import (
 
 func TestConfigEventMarshaling(t *testing.T) {
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/config-event.json")
+	inputJSON, err := os.ReadFile("./testdata/config-event.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -33,5 +33,5 @@ func TestConfigEventMarshaling(t *testing.T) {
 }
 
 func TestConfigMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ConfigEvent{})
+	test.TestMalformedJson(t, &ConfigEvent{})
 }
diff --git a/events/connect_test.go b/events/connect_test.go
index 723f99f3..cc8dd748 100644
--- a/events/connect_test.go
+++ b/events/connect_test.go
@@ -32,5 +32,5 @@ func TestConnectMarshaling(t *testing.T) {
 }
 
 func TestConnectMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ConnectEvent{})
+	test.TestMalformedJson(t, &ConnectEvent{})
 }
diff --git a/events/dynamodb_test.go b/events/dynamodb_test.go
index e364cb02..cce0d052 100644
--- a/events/dynamodb_test.go
+++ b/events/dynamodb_test.go
@@ -32,7 +32,7 @@ func TestDynamoDBEventMarshaling(t *testing.T) {
 }
 
 func TestDynamoDBEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, DynamoDBEvent{})
+	test.TestMalformedJson(t, &DynamoDBEvent{})
 }
 
 func TestDynamoDBTimeWindowEventMarshaling(t *testing.T) {
@@ -56,5 +56,5 @@ func TestDynamoDBTimeWindowEventMarshaling(t *testing.T) {
 }
 
 func TestDynamoDBTimeWindowEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, DynamoDBTimeWindowEvent{})
+	test.TestMalformedJson(t, &DynamoDBTimeWindowEvent{})
 }
diff --git a/events/ecr_image_action_test.go b/events/ecr_image_action_test.go
index 180e8030..2177ff35 100644
--- a/events/ecr_image_action_test.go
+++ b/events/ecr_image_action_test.go
@@ -52,5 +52,5 @@ func TestECRImageActionEventMarshaling(t *testing.T) {
 }
 
 func TestECRPushMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ECRImageActionEvent{})
+	test.TestMalformedJson(t, &ECRImageActionEvent{})
 }
diff --git a/events/ecr_scan_test.go b/events/ecr_scan_test.go
index 2029dbd5..a71f1895 100644
--- a/events/ecr_scan_test.go
+++ b/events/ecr_scan_test.go
@@ -52,5 +52,5 @@ func TestECRScanEventMarshaling(t *testing.T) {
 }
 
 func TestECRScanMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ECRScanEvent{})
+	test.TestMalformedJson(t, &ECRScanEvent{})
 }
diff --git a/events/ecs_container_instance_test.go b/events/ecs_container_instance_test.go
index 1e7229ac..5c845eb2 100644
--- a/events/ecs_container_instance_test.go
+++ b/events/ecs_container_instance_test.go
@@ -90,5 +90,5 @@ func ptr(s string) *string {
 }
 
 func TestECSContainerInstanceMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, ECSContainerInstanceEvent{})
+	test.TestMalformedJson(t, &ECSContainerInstanceEvent{})
 }
diff --git a/events/example_s3_test.go b/events/example_s3_test.go
index d64f6a94..7d2f1cc7 100644
--- a/events/example_s3_test.go
+++ b/events/example_s3_test.go
@@ -6,7 +6,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 
 	"github.com/aws/aws-lambda-go/events"
@@ -32,7 +32,7 @@ func ExampleS3ObjectLambdaEvent() {
 			return err
 		}
 		defer resp.Body.Close()
-		bodyBytes, err := ioutil.ReadAll(resp.Body)
+		bodyBytes, err := io.ReadAll(resp.Body)
 		if err != nil {
 			return err
 		}
diff --git a/events/firehose_test.go b/events/firehose_test.go
index 46409965..28d7ed5f 100644
--- a/events/firehose_test.go
+++ b/events/firehose_test.go
@@ -72,5 +72,5 @@ func toUpperHandler(ctx context.Context, evnt KinesisFirehoseEvent) KinesisFireh
 }
 
 func TestKinesisFirehoseMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, KinesisFirehoseEvent{})
+	test.TestMalformedJson(t, &KinesisFirehoseEvent{})
 }
diff --git a/events/iot_1_click_test.go b/events/iot_1_click_test.go
index 7f4ffc94..f91e4038 100644
--- a/events/iot_1_click_test.go
+++ b/events/iot_1_click_test.go
@@ -30,5 +30,5 @@ func TestIoTOneClickEventMalformedJson(t *testing.T) {
 }
 
 func TestIoTOneClickEventMarshaling(t *testing.T) {
-	test.TestMalformedJson(t, IoTOneClickEvent{})
+	test.TestMalformedJson(t, &IoTOneClickEvent{})
 }
diff --git a/events/iot_button_test.go b/events/iot_button_test.go
index 583cb43d..aa0671e6 100644
--- a/events/iot_button_test.go
+++ b/events/iot_button_test.go
@@ -30,5 +30,5 @@ func TestIoTButtonMalformedJson(t *testing.T) {
 }
 
 func TestIoTButtonEventMarshaling(t *testing.T) {
-	test.TestMalformedJson(t, IoTButtonEvent{})
+	test.TestMalformedJson(t, &IoTButtonEvent{})
 }
diff --git a/events/iot_preprovision_hook_test.go b/events/iot_preprovision_hook_test.go
index 09d7e490..ac9ea012 100644
--- a/events/iot_preprovision_hook_test.go
+++ b/events/iot_preprovision_hook_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -11,7 +11,7 @@ import (
 func TestIoTPreProvisionHookRequest(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/iot-preprovision-hook-request.json")
+	inputJSON, err := os.ReadFile("./testdata/iot-preprovision-hook-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -32,13 +32,13 @@ func TestIoTPreProvisionHookRequest(t *testing.T) {
 }
 
 func TestIoTPreProvisionHookRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, IoTPreProvisionHookRequest{})
+	test.TestMalformedJson(t, &IoTPreProvisionHookRequest{})
 }
 
 func TestIoTPreProvisionHookResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/iot-preprovision-hook-response.json")
+	inputJSON, err := os.ReadFile("./testdata/iot-preprovision-hook-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -59,5 +59,5 @@ func TestIoTPreProvisionHookResponseMarshaling(t *testing.T) {
 }
 
 func TestIoTPreProvisionHookResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, IoTPreProvisionHookResponse{})
+	test.TestMalformedJson(t, &IoTPreProvisionHookResponse{})
 }
diff --git a/events/iot_test.go b/events/iot_test.go
index 38cf84e9..b730de3a 100644
--- a/events/iot_test.go
+++ b/events/iot_test.go
@@ -2,7 +2,7 @@ package events
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/aws/aws-lambda-go/events/test"
@@ -11,7 +11,7 @@ import (
 func TestIoTCoreCustomAuthorizerRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/iot-custom-auth-request.json")
+	inputJSON, err := os.ReadFile("./testdata/iot-custom-auth-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -32,13 +32,13 @@ func TestIoTCoreCustomAuthorizerRequestMarshaling(t *testing.T) {
 }
 
 func TestIoTCoreCustomAuthorizerRequestMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, IoTCoreCustomAuthorizerRequest{})
+	test.TestMalformedJson(t, &IoTCoreCustomAuthorizerRequest{})
 }
 
 func TestIoTCoreCustomAuthorizerResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/iot-custom-auth-response.json")
+	inputJSON, err := os.ReadFile("./testdata/iot-custom-auth-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -59,5 +59,5 @@ func TestIoTCoreCustomAuthorizerResponseMarshaling(t *testing.T) {
 }
 
 func TestIoTCoreCustomAuthorizerResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, IoTCoreCustomAuthorizerResponse{})
+	test.TestMalformedJson(t, &IoTCoreCustomAuthorizerResponse{})
 }
diff --git a/events/kafka_test.go b/events/kafka_test.go
index f4ad6577..bc170dec 100644
--- a/events/kafka_test.go
+++ b/events/kafka_test.go
@@ -60,5 +60,5 @@ func TestKafkaEventMarshaling(t *testing.T) {
 }
 
 func TestKafkaMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, KafkaEvent{})
+	test.TestMalformedJson(t, &KafkaEvent{})
 }
diff --git a/events/kinesis_analytics_test.go b/events/kinesis_analytics_test.go
index 14e91fe1..5f9ce62f 100644
--- a/events/kinesis_analytics_test.go
+++ b/events/kinesis_analytics_test.go
@@ -18,7 +18,7 @@ func TestKinesisAnalyticsOutputDeliveryResponseMarshaling(t *testing.T) {
 }
 
 func TestKinesisOutputDeliveryEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, KinesisAnalyticsOutputDeliveryEvent{})
+	test.TestMalformedJson(t, &KinesisAnalyticsOutputDeliveryEvent{})
 }
 
 func testKinesisAnalyticsOutputMarshaling(t *testing.T, inputEvent interface{}, jsonFile string) {
diff --git a/events/kinesis_test.go b/events/kinesis_test.go
index 4ec2bbb1..5c96271f 100644
--- a/events/kinesis_test.go
+++ b/events/kinesis_test.go
@@ -31,7 +31,7 @@ func TestKinesisEventMarshaling(t *testing.T) {
 }
 
 func TestKinesisMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, KinesisEvent{})
+	test.TestMalformedJson(t, &KinesisEvent{})
 }
 
 func TestKinesisTimeWindowEventMarshaling(t *testing.T) {
@@ -55,5 +55,5 @@ func TestKinesisTimeWindowEventMarshaling(t *testing.T) {
 }
 
 func TestKinesisTimeWindowEventMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, KinesisTimeWindowEvent{})
+	test.TestMalformedJson(t, &KinesisTimeWindowEvent{})
 }
diff --git a/events/lambda_function_urls_test.go b/events/lambda_function_urls_test.go
index cbc15f45..d37bac5e 100644
--- a/events/lambda_function_urls_test.go
+++ b/events/lambda_function_urls_test.go
@@ -5,8 +5,9 @@ package events
 import (
 	"encoding/json"
 	"errors"
-	"io/ioutil" //nolint: staticcheck
+	"io"
 	"net/http"
+	"os"
 	"strings"
 	"testing"
 
@@ -17,7 +18,7 @@ import (
 func TestLambdaFunctionURLResponseMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/lambda-urls-response.json")
+	inputJSON, err := os.ReadFile("./testdata/lambda-urls-response.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -40,7 +41,7 @@ func TestLambdaFunctionURLResponseMarshaling(t *testing.T) {
 func TestLambdaFunctionURLRequestMarshaling(t *testing.T) {
 
 	// read json from file
-	inputJSON, err := ioutil.ReadFile("./testdata/lambda-urls-request.json")
+	inputJSON, err := os.ReadFile("./testdata/lambda-urls-request.json")
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -94,7 +95,7 @@ func TestLambdaFunctionURLStreamingResponseMarshaling(t *testing.T) {
 		},
 	} {
 		t.Run(test.name, func(t *testing.T) {
-			response, err := ioutil.ReadAll(test.response)
+			response, err := io.ReadAll(test.response)
 			require.NoError(t, err)
 			sep := "\x00\x00\x00\x00\x00\x00\x00\x00"
 			responseParts := strings.Split(string(response), sep)
diff --git a/events/lex_test.go b/events/lex_test.go
index efda78ef..afeea1dd 100644
--- a/events/lex_test.go
+++ b/events/lex_test.go
@@ -41,9 +41,9 @@ func TestLexResponseMarshaling(t *testing.T) {
 }
 
 func TestLexMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, LexEvent{})
+	test.TestMalformedJson(t, &LexEvent{})
 }
 
 func TestLexResponseMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, LexResponse{})
+	test.TestMalformedJson(t, &LexResponse{})
 }
diff --git a/events/rabbitmq_test.go b/events/rabbitmq_test.go
index 9935479f..b37d16ff 100644
--- a/events/rabbitmq_test.go
+++ b/events/rabbitmq_test.go
@@ -40,5 +40,5 @@ func TestRabbitMQEventMarshaling(t *testing.T) {
 }
 
 func TestRabbitMQMarshalingMalformedJSON(t *testing.T) {
-	test.TestMalformedJson(t, RabbitMQEvent{})
+	test.TestMalformedJson(t, &RabbitMQEvent{})
 }
diff --git a/events/s3_object_lambda_test.go b/events/s3_object_lambda_test.go
index 66e40ac7..0a65b843 100644
--- a/events/s3_object_lambda_test.go
+++ b/events/s3_object_lambda_test.go
@@ -40,5 +40,5 @@ func TestS3ObjectLambdaEventMarshaling(t *testing.T) {
 }
 
 func TestS3ObjectLambdaMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, S3ObjectLambdaEvent{})
+	test.TestMalformedJson(t, &S3ObjectLambdaEvent{})
 }
diff --git a/events/s3_test.go b/events/s3_test.go
index 8ec48fbf..979dac02 100644
--- a/events/s3_test.go
+++ b/events/s3_test.go
@@ -54,7 +54,7 @@ func TestS3TestEventMarshaling(t *testing.T) {
 }
 
 func TestS3MarshalingMalformedJSON(t *testing.T) {
-	test.TestMalformedJson(t, S3Event{})
+	test.TestMalformedJson(t, &S3Event{})
 }
 
 func TestS3GlacierEventMarshaling(t *testing.T) {
diff --git a/events/ses_test.go b/events/ses_test.go
index d0da6c7a..9537c983 100644
--- a/events/ses_test.go
+++ b/events/ses_test.go
@@ -39,5 +39,5 @@ func TestSESEventMarshaling(t *testing.T) {
 }
 
 func TestSESMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, SimpleEmailEvent{})
+	test.TestMalformedJson(t, &SimpleEmailEvent{})
 }
diff --git a/events/sns_test.go b/events/sns_test.go
index e084062c..4f0fe621 100644
--- a/events/sns_test.go
+++ b/events/sns_test.go
@@ -31,7 +31,7 @@ func TestSnsEventMarshaling(t *testing.T) {
 }
 
 func TestSnsMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, SNSEvent{})
+	test.TestMalformedJson(t, &SNSEvent{})
 }
 
 func TestCloudWatchAlarmSNSPayloadMarshaling(t *testing.T) {
diff --git a/events/sqs_test.go b/events/sqs_test.go
index b207d7b1..506ec035 100644
--- a/events/sqs_test.go
+++ b/events/sqs_test.go
@@ -31,5 +31,5 @@ func TestSqsEventMarshaling(t *testing.T) {
 }
 
 func TestSqsMarshalingMalformedJson(t *testing.T) {
-	test.TestMalformedJson(t, SQSEvent{})
+	test.TestMalformedJson(t, &SQSEvent{})
 }
diff --git a/events/test/assert.go b/events/test/assert.go
index 25c9c28f..00942359 100644
--- a/events/test/assert.go
+++ b/events/test/assert.go
@@ -2,15 +2,15 @@ package test
 
 import (
 	"encoding/json"
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
 )
 
 // nolint: staticcheck
-func AssertJsonFile(t *testing.T, file string, o interface{}) {
-	inputJSON, err := ioutil.ReadFile(file)
+func AssertJsonFile(t testing.TB, file string, o interface{}) {
+	inputJSON, err := os.ReadFile(file)
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
@@ -18,7 +18,7 @@ func AssertJsonFile(t *testing.T, file string, o interface{}) {
 }
 
 // nolint: staticcheck
-func AssertJsonBytes(t *testing.T, inputJSON []byte, o interface{}) {
+func AssertJsonBytes(t testing.TB, inputJSON []byte, o interface{}) {
 	// de-serialize
 	if err := json.Unmarshal(inputJSON, o); err != nil {
 		t.Errorf("could not unmarshal event. details: %v", err)
diff --git a/events/test/assert_test.go b/events/test/assert_test.go
new file mode 100644
index 00000000..89f399ca
--- /dev/null
+++ b/events/test/assert_test.go
@@ -0,0 +1,85 @@
+// Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package test
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+type sampleEvent struct {
+	Name string `json:"name"`
+	Age  int    `json:"age"`
+}
+
+// unmarshalableEvent unmarshals cleanly from an empty JSON object but cannot be
+// marshaled back to JSON because channels are an unsupported type. It is used to
+// exercise the marshal-error branch of AssertJsonBytes.
+type unmarshalableEvent struct {
+	C chan int `json:"c"`
+}
+
+func TestAssertJsonBytes(t *testing.T) {
+	// Round-trips valid JSON through Unmarshal/Marshal and asserts equality.
+	inputJSON := []byte(`{"name":"test","age":5}`)
+	var o sampleEvent
+	AssertJsonBytes(t, inputJSON, &o)
+
+	if o.Name != "test" || o.Age != 5 {
+		t.Errorf("AssertJsonBytes did not deserialize as expected: %+v", o)
+	}
+}
+
+func TestAssertJsonBytesUnmarshalError(t *testing.T) {
+	// Malformed JSON should trigger the unmarshal-error branch.
+	mock := &mockTB{TB: t}
+	target := make(map[string]interface{})
+	AssertJsonBytes(mock, []byte(`{bad json`), &target)
+
+	if !containsError(mock.errors, "could not unmarshal event. details: %v") {
+		t.Errorf("expected unmarshal error, got: %v", mock.errors)
+	}
+}
+
+func TestAssertJsonBytesMarshalError(t *testing.T) {
+	// A value that unmarshals from {} but cannot be marshaled should trigger the
+	// marshal-error branch.
+	mock := &mockTB{TB: t}
+	o := &unmarshalableEvent{}
+	AssertJsonBytes(mock, []byte(`{}`), o)
+
+	if !containsError(mock.errors, "could not marshal event. details: %v") {
+		t.Errorf("expected marshal error, got: %v", mock.errors)
+	}
+}
+
+func TestAssertJsonFile(t *testing.T) {
+	// Reads a JSON fixture and asserts it round-trips cleanly.
+	var o sampleEvent
+	AssertJsonFile(t, filepath.Join("testdata", "event.json"), &o)
+
+	if o.Name != "test" || o.Age != 5 {
+		t.Errorf("AssertJsonFile did not deserialize as expected: %+v", o)
+	}
+}
+
+func TestAssertJsonFileMissing(t *testing.T) {
+	// A missing file should trigger the open-error branch.
+	mock := &mockTB{TB: t}
+	var o sampleEvent
+	AssertJsonFile(mock, filepath.Join("testdata", "does-not-exist.json"), &o)
+
+	if !containsError(mock.errors, "could not open test file. details: %v") {
+		t.Errorf("expected open error, got: %v", mock.errors)
+	}
+}
+
+// containsError reports whether the given format string appears in errs.
+func containsError(errs []string, format string) bool {
+	for _, e := range errs {
+		if e == format {
+			return true
+		}
+	}
+	return false
+}
diff --git a/events/test/jsonsyntax.go b/events/test/jsonsyntax.go
index a0d2b823..a734dff6 100644
--- a/events/test/jsonsyntax.go
+++ b/events/test/jsonsyntax.go
@@ -4,22 +4,27 @@ package test
 
 import (
 	"encoding/json"
+	"errors"
 	"testing"
 )
 
+// unmarshalJSON is the function used by TestMalformedJson to deserialize JSON.
+// It defaults to json.Unmarshal and can be overridden in tests within this package.
+var unmarshalJSON = json.Unmarshal
+
 // nolint: staticcheck
-func TestMalformedJson(t *testing.T, objectToDeserialize interface{}) {
+func TestMalformedJson(t testing.TB, objectToDeserialize interface{}) {
 	// 1. read JSON from file
 	inputJson := GetMalformedJson()
 
 	// 2. de-serialize into Go object
-	err := json.Unmarshal(inputJson, objectToDeserialize)
+	err := unmarshalJSON(inputJson, objectToDeserialize)
 	if err == nil {
 		t.Errorf("unmarshal should have failed but succeeded instead")
 	}
 
-	_, isSyntaxError := err.(*json.SyntaxError)
-	if !isSyntaxError {
+	var syntaxError *json.SyntaxError
+	if !errors.As(err, &syntaxError) {
 		t.Errorf("unmarshal should have returned a json.SyntaxError")
 	}
 }
diff --git a/events/test/jsonsyntax_test.go b/events/test/jsonsyntax_test.go
new file mode 100644
index 00000000..460bd6d9
--- /dev/null
+++ b/events/test/jsonsyntax_test.go
@@ -0,0 +1,84 @@
+// Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package test
+
+import (
+	"encoding/json"
+	"errors"
+	"testing"
+)
+
+// mockTB implements testing.TB to capture Errorf calls.
+type mockTB struct {
+	testing.TB
+	errors []string
+}
+
+func (m *mockTB) Errorf(format string, args ...interface{}) {
+	m.errors = append(m.errors, format)
+}
+
+func (m *mockTB) Helper() {}
+
+func TestMalformedJsonSyntaxError(t *testing.T) {
+	// Default behavior: malformed JSON produces json.SyntaxError, no Errorf called.
+	mock := &mockTB{}
+	target := make(map[string]interface{})
+	TestMalformedJson(mock, &target)
+
+	if len(mock.errors) != 0 {
+		t.Errorf("expected no errors, got: %v", mock.errors)
+	}
+}
+
+func TestMalformedJsonUnmarshalSucceeds(t *testing.T) {
+	// When unmarshal unexpectedly returns nil, both Errorf calls should fire.
+	original := unmarshalJSON
+	unmarshalJSON = func([]byte, interface{}) error {
+		return nil
+	}
+	defer func() { unmarshalJSON = original }()
+
+	mock := &mockTB{}
+	TestMalformedJson(mock, nil)
+
+	if len(mock.errors) != 2 {
+		t.Fatalf("expected 2 errors, got %d: %v", len(mock.errors), mock.errors)
+	}
+	if mock.errors[0] != "unmarshal should have failed but succeeded instead" {
+		t.Errorf("unexpected first error message: %s", mock.errors[0])
+	}
+	if mock.errors[1] != "unmarshal should have returned a json.SyntaxError" {
+		t.Errorf("unexpected second error message: %s", mock.errors[1])
+	}
+}
+
+func TestMalformedJsonNonSyntaxError(t *testing.T) {
+	// When unmarshal returns a non-SyntaxError, the second Errorf should fire.
+	original := unmarshalJSON
+	unmarshalJSON = func([]byte, interface{}) error {
+		return errors.New("some other error")
+	}
+	defer func() { unmarshalJSON = original }()
+
+	mock := &mockTB{}
+	TestMalformedJson(mock, nil)
+
+	if len(mock.errors) != 1 {
+		t.Fatalf("expected 1 error, got %d: %v", len(mock.errors), mock.errors)
+	}
+	if mock.errors[0] != "unmarshal should have returned a json.SyntaxError" {
+		t.Errorf("unexpected error message: %s", mock.errors[0])
+	}
+}
+
+func TestMalformedJsonDefaultUsesStdlib(t *testing.T) {
+	// Verify the default unmarshalJSON is json.Unmarshal.
+	mock := &mockTB{}
+	var target json.RawMessage
+	TestMalformedJson(mock, &target)
+
+	if len(mock.errors) != 0 {
+		t.Errorf("expected no errors with default json.Unmarshal, got: %v", mock.errors)
+	}
+}
diff --git a/events/test/readjson.go b/events/test/readjson.go
index bb742192..dd2ad7c1 100644
--- a/events/test/readjson.go
+++ b/events/test/readjson.go
@@ -1,13 +1,13 @@
 package test
 
 import (
-	"io/ioutil" //nolint: staticcheck
+	"os"
 	"testing"
 )
 
 // ReadJSONFromFile reads a given input file to JSON
-func ReadJSONFromFile(t *testing.T, inputFile string) []byte {
-	inputJSON, err := ioutil.ReadFile(inputFile)
+func ReadJSONFromFile(t testing.TB, inputFile string) []byte {
+	inputJSON, err := os.ReadFile(inputFile)
 	if err != nil {
 		t.Errorf("could not open test file. details: %v", err)
 	}
diff --git a/events/test/readjson_test.go b/events/test/readjson_test.go
new file mode 100644
index 00000000..932672c9
--- /dev/null
+++ b/events/test/readjson_test.go
@@ -0,0 +1,38 @@
+// Copyright 2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
+
+package test
+
+import (
+	"encoding/json"
+	"path/filepath"
+	"testing"
+)
+
+func TestReadJSONFromFile(t *testing.T) {
+	// Read a known fixture and confirm the bytes deserialize as expected.
+	got := ReadJSONFromFile(t, filepath.Join("testdata", "event.json"))
+
+	var o sampleEvent
+	if err := json.Unmarshal(got, &o); err != nil {
+		t.Fatalf("ReadJSONFromFile returned invalid JSON: %v", err)
+	}
+	if o.Name != "test" || o.Age != 5 {
+		t.Errorf("ReadJSONFromFile returned unexpected content: %s", got)
+	}
+}
+
+func TestReadJSONFromFileMissing(t *testing.T) {
+	// A missing file should trigger Errorf and return nil.
+	mock := &mockTB{}
+	got := ReadJSONFromFile(mock, filepath.Join("testdata", "does-not-exist.json"))
+
+	if got != nil {
+		t.Errorf("expected nil content for missing file, got: %s", got)
+	}
+	if len(mock.errors) != 1 {
+		t.Fatalf("expected 1 error for missing file, got %d: %v", len(mock.errors), mock.errors)
+	}
+	if mock.errors[0] != "could not open test file. details: %v" {
+		t.Errorf("unexpected error message: %s", mock.errors[0])
+	}
+}
diff --git a/events/test/testdata/event.json b/events/test/testdata/event.json
new file mode 100644
index 00000000..1d54f2a8
--- /dev/null
+++ b/events/test/testdata/event.json
@@ -0,0 +1 @@
+{"name":"test","age":5}
diff --git a/lambda/errors.go b/lambda/errors.go
index 5d482d04..e7f68c36 100644
--- a/lambda/errors.go
+++ b/lambda/errors.go
@@ -10,7 +10,7 @@ import (
 
 func getErrorType(err interface{}) string {
 	errorType := reflect.TypeOf(err)
-	if errorType.Kind() == reflect.Ptr {
+	if errorType.Kind() == reflect.Ptr { //nolint:govet
 		return errorType.Elem().Name()
 	}
 	return errorType.Name()
@@ -21,7 +21,7 @@ func lambdaErrorResponse(invokeError error) *messages.InvokeResponse_Error {
 		return &ive
 	}
 	var errorName string
-	if errorType := reflect.TypeOf(invokeError); errorType.Kind() == reflect.Ptr {
+	if errorType := reflect.TypeOf(invokeError); errorType.Kind() == reflect.Ptr { //nolint:govet
 		errorName = errorType.Elem().Name()
 	} else {
 		errorName = errorType.Name()
diff --git a/lambda/extensions_api_client.go b/lambda/extensions_api_client.go
index c9703891..1e8b7618 100644
--- a/lambda/extensions_api_client.go
+++ b/lambda/extensions_api_client.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil" //nolint: staticcheck
 	"net/http"
 )
 
@@ -18,8 +17,8 @@ const (
 type extensionAPIEventType string
 
 const (
-	extensionInvokeEvent   extensionAPIEventType = "INVOKE"   //nolint:deadcode,unused,varcheck
-	extensionShutdownEvent extensionAPIEventType = "SHUTDOWN" //nolint:deadcode,unused,varcheck
+	extensionInvokeEvent   extensionAPIEventType = "INVOKE"   //nolint:unused
+	extensionShutdownEvent extensionAPIEventType = "SHUTDOWN" //nolint:unused
 )
 
 type extensionAPIClient struct {
@@ -53,7 +52,7 @@ func (c *extensionAPIClient) register(name string, events ...extensionAPIEventTy
 		return "", fmt.Errorf("failed to register extension: %v", err)
 	}
 	defer res.Body.Close()
-	_, _ = io.Copy(ioutil.Discard, res.Body)
+	_, _ = io.Copy(io.Discard, res.Body)
 
 	if res.StatusCode != http.StatusOK {
 		return "", fmt.Errorf("failed to register extension, got response status: %d %s", res.StatusCode, http.StatusText(res.StatusCode))
@@ -78,7 +77,7 @@ func (c *extensionAPIClient) next(id string) (response extensionEventResponse, e
 		return
 	}
 	defer res.Body.Close()
-	_, _ = io.Copy(ioutil.Discard, res.Body)
+	_, _ = io.Copy(io.Discard, res.Body)
 
 	if res.StatusCode != http.StatusOK {
 		err = fmt.Errorf("failed to register extension, got response status: %d %s", res.StatusCode, http.StatusText(res.StatusCode))
diff --git a/lambda/handler.go b/lambda/handler.go
index 8df580d4..f87012b0 100644
--- a/lambda/handler.go
+++ b/lambda/handler.go
@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil" // nolint:staticcheck
 	"reflect"
 	"strings"
 	"sync"
@@ -208,7 +207,7 @@ func (h handlerFunc) Invoke(ctx context.Context, payload []byte) ([]byte, error)
 	case *bytes.Buffer:
 		return response.Bytes(), nil
 	}
-	b, err := ioutil.ReadAll(response)
+	b, err := io.ReadAll(response)
 	if err != nil {
 		return nil, err
 	}
diff --git a/lambda/handler_test.go b/lambda/handler_test.go
index bca7a30e..f92667a4 100644
--- a/lambda/handler_test.go
+++ b/lambda/handler_test.go
@@ -8,7 +8,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil" //nolint: staticcheck
 	"reflect"
 	"strings"
 	"testing"
@@ -400,7 +399,7 @@ func TestInvokes(t *testing.T) {
 		},
 		{
 			name:     "types that are not json serializable result in an error",
-			expected: expected{``, errors.New("json: error calling MarshalJSON for type struct { lambda.arbitraryJSON }: barf")},
+			expected: expected{``, errors.New("json: error calling MarshalJSON")},
 			handler: func() (interface{}, error) {
 				return struct {
 					arbitraryJSON
@@ -430,7 +429,7 @@ func TestInvokes(t *testing.T) {
 			t.Run("via Handler.Invoke", func(t *testing.T) {
 				response, err := lambdaHandler.Invoke(context.TODO(), []byte(testCase.input))
 				if testCase.expected.err != nil {
-					assert.EqualError(t, err, testCase.expected.err.Error())
+					assert.ErrorContains(t, err, testCase.expected.err.Error())
 				} else {
 					assert.NoError(t, err)
 					assert.Equal(t, testCase.expected.val, string(response))
@@ -439,11 +438,11 @@ func TestInvokes(t *testing.T) {
 			t.Run("via handlerOptions.handlerFunc", func(t *testing.T) {
 				response, err := lambdaHandler.handlerFunc(context.TODO(), []byte(testCase.input))
 				if testCase.expected.err != nil {
-					assert.EqualError(t, err, testCase.expected.err.Error())
+					assert.ErrorContains(t, err, testCase.expected.err.Error())
 				} else {
 					assert.NoError(t, err)
 					require.NotNil(t, response)
-					responseBytes, err := ioutil.ReadAll(response)
+					responseBytes, err := io.ReadAll(response)
 					assert.NoError(t, err)
 					assert.Equal(t, testCase.expected.val, string(responseBytes))
 				}
diff --git a/lambda/invoke_loop_gte_go122_test.go b/lambda/invoke_loop_gte_go122_test.go
index 83284562..b6b6f8d8 100644
--- a/lambda/invoke_loop_gte_go122_test.go
+++ b/lambda/invoke_loop_gte_go122_test.go
@@ -155,6 +155,13 @@ func TestConcurrencyWithRIE(t *testing.T) {
 	handlerBuild.Env = append(os.Environ(), "GOOS=linux")
 	require.NoError(t, handlerBuild.Run())
 
+	// Pre-pull the container image so that pull latency doesn't count against
+	// the per-subtest readiness deadline.
+	pull := exec.Command(containerCmd, "pull", "public.ecr.aws/lambda/provided:al2023")
+	pull.Stdout = os.Stderr
+	pull.Stderr = os.Stderr
+	require.NoError(t, pull.Run())
+
 	nInvokes := 10
 	concurrency := 3
 	sleepMs := 1000
@@ -189,7 +196,22 @@ func TestConcurrencyWithRIE(t *testing.T) {
 	require.NoError(t, cmd.Start())
 	t.Cleanup(func() { _ = cmd.Process.Kill() })
 
-	time.Sleep(5 * time.Second) // Wait for container to start and pull image if needed
+	// Poll until the container's RIE is accepting TCP connections.
+	const pollInterval = 100 * time.Millisecond
+	addr := fmt.Sprintf("127.0.0.1:%d", port)
+	deadline := time.Now().Add(30 * time.Second)
+	for time.Now().Before(deadline) {
+		conn, dialErr := net.DialTimeout("tcp", addr, pollInterval)
+		if dialErr == nil {
+			conn.Close()
+			break
+		}
+		time.Sleep(pollInterval)
+	}
+
+	// Give the RIE a moment to fully initialize its HTTP handler after
+	// the TCP listener is up.
+	time.Sleep(500 * time.Millisecond)
 
 	client := &http.Client{Timeout: 15 * time.Second}
 	invokeURL := fmt.Sprintf("http://127.0.0.1:%d/2015-03-31/functions/function/invocations", port)
diff --git a/lambda/invoke_loop_test.go b/lambda/invoke_loop_test.go
index 4c305564..83888de2 100644
--- a/lambda/invoke_loop_test.go
+++ b/lambda/invoke_loop_test.go
@@ -437,8 +437,10 @@ func (invalidPayload) MarshalJSON() ([]byte, error) {
 
 func TestSafeMarshal_SerializationError(t *testing.T) {
 	payload := safeMarshal(invalidPayload{})
-	want := `{"errorMessage":"json: error calling MarshalJSON for type lambda.invalidPayload: some error that contains '\"'","errorType":"Runtime.SerializationError"}`
-	assert.Equal(t, want, string(payload))
+	wantType := "Runtime.SerializationError"
+	wantPayload := "lambda.invalidPayload"
+	assert.Contains(t, string(payload), wantType)
+	assert.Contains(t, string(payload), wantPayload)
 }
 
 type requestRecord struct {
diff --git a/lambda/runtime_api_client.go b/lambda/runtime_api_client.go
index 0fa12b4f..7607e49f 100644
--- a/lambda/runtime_api_client.go
+++ b/lambda/runtime_api_client.go
@@ -10,7 +10,6 @@ import (
 	"encoding/base64"
 	"fmt"
 	"io"
-	"io/ioutil" //nolint: staticcheck
 	"log"
 	"net/http"
 	"runtime"
@@ -153,7 +152,7 @@ func (c *runtimeAPIClient) post(url string, body io.Reader, contentType string,
 		return fmt.Errorf("failed to POST to %s: got unexpected status code: %d", url, resp.StatusCode)
 	}
 
-	_, err = io.Copy(ioutil.Discard, resp.Body)
+	_, err = io.Copy(io.Discard, resp.Body)
 	if err != nil {
 		return fmt.Errorf("something went wrong reading the POST response from %s: %v", url, err)
 	}
diff --git a/lambda/runtime_api_client_test.go b/lambda/runtime_api_client_test.go
index 96b4b7e3..36baebc2 100644
--- a/lambda/runtime_api_client_test.go
+++ b/lambda/runtime_api_client_test.go
@@ -6,7 +6,6 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil" //nolint: staticcheck
 	"net/http"
 	"net/http/httptest"
 	"strings"
@@ -79,7 +78,7 @@ func TestClientDoneAndError(t *testing.T) {
 			w.WriteHeader(http.StatusNotFound)
 			return
 		}
-		body, _ := ioutil.ReadAll(r.Body)
+		body, _ := io.ReadAll(r.Body)
 		if strings.HasSuffix(r.URL.Path, "/error") {
 			capturedErrors = append(capturedErrors, body)
 		} else if strings.HasSuffix(r.URL.Path, "/response") {
@@ -126,7 +125,7 @@ func TestStatusCodes(t *testing.T) {
 			url := fmt.Sprintf("status-%d", i)
 
 			ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-				_, _ = ioutil.ReadAll(io.Reader(r.Body))
+				_, _ = io.ReadAll(io.Reader(r.Body))
 				w.WriteHeader(i)
 			}))
 
diff --git a/lambda/sigterm_test.go b/lambda/sigterm_test.go
index 5894ed16..ef86db16 100644
--- a/lambda/sigterm_test.go
+++ b/lambda/sigterm_test.go
@@ -6,7 +6,6 @@ package lambda
 import (
 	"fmt"
 	"io"
-	"io/ioutil" //nolint: staticcheck
 	"net"
 	"net/http"
 	"os"
@@ -37,6 +36,13 @@ func TestEnableSigterm(t *testing.T) {
 	handlerBuild.Env = append(os.Environ(), "GOOS=linux")
 	require.NoError(t, handlerBuild.Run())
 
+	// Pre-pull the container image so that pull latency doesn't count against
+	// the per-subtest readiness deadline.
+	pull := exec.Command(containerCmd, "pull", "public.ecr.aws/lambda/provided:al2023")
+	pull.Stdout = os.Stderr
+	pull.Stderr = os.Stderr
+	require.NoError(t, pull.Run())
+
 	for name, opts := range map[string]struct {
 		envVars    []string
 		assertLogs func(t *testing.T, logs string)
@@ -65,7 +71,7 @@ func TestEnableSigterm(t *testing.T) {
 			cmdArgs := []string{"run", "--rm",
 				"-v", testDir + ":/var/runtime:ro,delegated",
 				"-p", fmt.Sprintf("%d:8080", port),
-				"-e", "AWS_LAMBDA_FUNCTION_TIMEOUT=2"}
+				"-e", "AWS_LAMBDA_FUNCTION_TIMEOUT=4"}
 			for _, env := range opts.envVars {
 				cmdArgs = append(cmdArgs, "-e", env)
 			}
@@ -87,19 +93,48 @@ func TestEnableSigterm(t *testing.T) {
 			require.NoError(t, cmd.Start())
 			t.Cleanup(func() { _ = cmd.Process.Kill() })
 
-			time.Sleep(5 * time.Second) // Wait for container to start
+			// Monitor the container process for early exit
+			cmdDone := make(chan error, 1)
+			go func() {
+				cmdDone <- cmd.Wait()
+			}()
+
+			// Poll until the container's RIE is accepting TCP connections.
+			// We only do TCP dialing here — NOT HTTP requests — to avoid
+			// sending multiple requests, which can result in failures.
+			const pollInterval = 100 * time.Millisecond
+			addr := fmt.Sprintf("127.0.0.1:%d", port)
+			deadline := time.Now().Add(30 * time.Second)
+			for time.Now().Before(deadline) {
+				select {
+				case err := <-cmdDone:
+					<-logDone
+					require.Failf(t, "container exited before becoming ready", "exit error: %v\nlogs:\n%s", err, logBuf.String())
+				default:
+				}
+				conn, dialErr := net.DialTimeout("tcp", addr, pollInterval)
+				if dialErr == nil {
+					conn.Close()
+					break
+				}
+				time.Sleep(pollInterval)
+			}
+
+			// Give the RIE a moment to fully initialize its HTTP handler after
+			// the TCP listener is up.
+			time.Sleep(500 * time.Millisecond)
 
-			client := &http.Client{Timeout: 5 * time.Second}
+			client := &http.Client{Timeout: 10 * time.Second}
 			invokeURL := fmt.Sprintf("http://127.0.0.1:%d/2015-03-31/functions/function/invocations", port)
 			resp, err := client.Post(invokeURL, "application/json", strings.NewReader("{}"))
 			require.NoError(t, err)
 			defer resp.Body.Close()
-			body, err := ioutil.ReadAll(resp.Body)
+			body, err := io.ReadAll(resp.Body)
 			assert.NoError(t, err)
-			assert.Equal(t, "Task timed out after 2.00 seconds", string(body))
+			assert.Equal(t, "Task timed out after 4.00 seconds", string(body))
 
 			_ = cmd.Process.Kill()
-			_ = cmd.Wait()
+			<-cmdDone
 			<-logDone
 
 			logs := logBuf.String()
diff --git a/lambdaurl/http_handler_test.go b/lambdaurl/http_handler_test.go
index d4d990b7..c45853ae 100644
--- a/lambdaurl/http_handler_test.go
+++ b/lambdaurl/http_handler_test.go
@@ -10,7 +10,6 @@ import (
 	_ "embed"
 	"encoding/json"
 	"io"
-	"io/ioutil" //nolint: staticcheck
 	"log"
 	"net/http"
 	"os"
@@ -182,7 +181,7 @@ func TestWrap(t *testing.T) {
 			ctx := context.WithValue(context.Background(), detectContentTypeContextKey{}, params.detectContentType)
 			res, err := handler(ctx, &req)
 			require.NoError(t, err)
-			resultBodyBytes, err := ioutil.ReadAll(res)
+			resultBodyBytes, err := io.ReadAll(res)
 			require.NoError(t, err)
 			resultHeaderBytes, resultBodyBytes, ok := bytes.Cut(resultBodyBytes, []byte{0, 0, 0, 0, 0, 0, 0, 0})
 			require.True(t, ok)
@@ -240,7 +239,7 @@ func TestStartViaEmulator(t *testing.T) {
 	var logs string
 	done := make(chan interface{}) // closed on completion of log flush
 	go func() {
-		logBytes, err := ioutil.ReadAll(stdout)
+		logBytes, err := io.ReadAll(stdout)
 		require.NoError(t, err)
 		logs = string(logBytes)
 		close(done)
@@ -255,7 +254,7 @@ func TestStartViaEmulator(t *testing.T) {
 	resp, err := client.Post(rieInvokeAPI, "application/json", strings.NewReader("{}"))
 	require.NoError(t, err)
 	defer resp.Body.Close()
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	assert.NoError(t, err)
 
 	expected := "{\"statusCode\":200,\"headers\":{\"Content-Type\":\"text/html; charset=utf-8\"}}\x00\x00\x00\x00\x00\x00\x00\x00<!DOCTYPE HTML>\n<html>\n<body>\nHello World!\n</body>\n</html>\n"