diff --git a/errors_test.go b/errors_test.go
index 2089b2f7..734a4ffc 100644
--- a/errors_test.go
+++ b/errors_test.go
@@ -125,7 +125,7 @@ func TestWrapf(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		got := Wrapf(tt.err, tt.message).Error()
+		got := Wrapf(tt.err, "%s", tt.message).Error()
 		if got != tt.want {
 			t.Errorf("Wrapf(%v, %q): got: %v, want %v", tt.err, tt.message, got, tt.want)
 		}
@@ -217,7 +217,7 @@ func TestWithMessagef(t *testing.T) {
 	}
 
 	for _, tt := range tests {
-		got := WithMessagef(tt.err, tt.message).Error()
+		got := WithMessagef(tt.err, "%s", tt.message).Error()
 		if got != tt.want {
 			t.Errorf("WithMessage(%v, %q): got: %q, want %q", tt.err, tt.message, got, tt.want)
 		}
diff --git a/go.mod b/go.mod
new file mode 100644
index 00000000..144fc712
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,4 @@
+module github.com/pkg/errors
+
+go 1.18
+