Add Spector tests for File type with content type variations

.chronus/changes/copilot-add-spector-test-file-content-type-2026-0-29-19-4-24.md

@@ -0,0 +1,7 @@
+---
+changeKind: feature
+packages:
+  - "@typespec/http-specs"
+---
+
+Add Spector tests for File type with various content types (body and multipart)

packages/http-specs/spec-summary.md

@@ -2050,6 +2050,68 @@ Content-Type: image/jpg
 --abcde12345--
 ```
 
+### Payload_MultiPart_FormData_File_uploadFileArray
+
+- Endpoint: `post /multipart/form-data/file/file-array`
+
+Test multiple File instances in multipart form data.
+Expected request:
+
+```
+POST /multipart/form-data/file/file-array HTTP/1.1
+Content-Type: multipart/form-data; boundary=abcde12345
+
+--abcde12345
+Content-Disposition: form-data; name="files"; filename="image1.png"
+Content-Type: image/png
+
+{…file content of image.png…}
+--abcde12345
+Content-Disposition: form-data; name="files"; filename="image2.png"
+Content-Type: image/png
+
+{…file content of image.png…}
+--abcde12345--
+```
+
+### Payload_MultiPart_FormData_File_uploadFileRequiredFilename
+
+- Endpoint: `post /multipart/form-data/file/required-filename`
+
+Test File type in multipart form data with required filename.
+Expected request:
+
+```
+POST /multipart/form-data/file/required-filename HTTP/1.1
+Content-Type: multipart/form-data; boundary=abcde12345
+
+--abcde12345
+Content-Disposition: form-data; name="file"; filename="image.png"
+Content-Type: image/png
+
+{…file content of image.png…}
+--abcde12345--
+```
+
+### Payload_MultiPart_FormData_File_uploadFileSpecificContentType
+
+- Endpoint: `post /multipart/form-data/file/specific-content-type`
+
+Test File type in multipart form data with specific content type.
+Expected request:
+
+```
+POST /multipart/form-data/file/specific-content-type HTTP/1.1
+Content-Type: multipart/form-data; boundary=abcde12345
+
+--abcde12345
+Content-Disposition: form-data; name="file"; filename="image.png"
+Content-Type: image/png
+
+{…file content of image.png…}
+--abcde12345--
+```
+
 ### Payload_MultiPart_FormData_fileArrayAndBasic
 
 - Endpoint: `post /multipart/form-data/complex-parts`
@@ -5210,6 +5272,90 @@ Expect to send a known value. Mock api expect to receive 'Monday'
 
 Expect to handle an unknown value. Mock api expect to receive 'Weekend'
 
+### Type_File_Body_downloadFileDefaultContentType
+
+- Endpoint: `get /type/file/body/response/default-content-type`
+
+Test File type as response body with unspecified content type.
+The File type accepts any content type. For testing, server will return image/png.
+Expected response:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
+### Type_File_Body_downloadFileJsonContentType
+
+- Endpoint: `get /type/file/body/response/json-content-type`
+
+Test File type as response body with JSON content type.
+Expected response:
+
+- Content-Type header: application/json
+- Body: JSON content with file data
+
+### Type_File_Body_downloadFileMultipleContentTypes
+
+- Endpoint: `get /type/file/body/response/multiple-content-types`
+
+Test File type as response body with multiple allowed content types.
+Service will return image/png.
+Expected response:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
+### Type_File_Body_downloadFileSpecificContentType
+
+- Endpoint: `get /type/file/body/response/specific-content-type`
+
+Test File type as response body with specific content type.
+Expected response:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
+### Type_File_Body_uploadFileDefaultContentType
+
+- Endpoint: `post /type/file/body/request/default-content-type`
+
+Test File type as request body with unspecified content type.
+The File type accepts any content type. For testing, sender will use image/png.
+Expected request:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
+### Type_File_Body_uploadFileJsonContentType
+
+- Endpoint: `post /type/file/body/request/json-content-type`
+
+Test File type as request body with JSON content type.
+Expected request:
+
+- Content-Type header: application/json
+- Body: JSON content with file data
+
+### Type_File_Body_uploadFileMultipleContentTypes
+
+- Endpoint: `post /type/file/body/request/multiple-content-types`
+
+Test File type as request body with multiple allowed content types (image/png or image/jpeg).
+Client should send image/png.
+Expected request:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
+### Type_File_Body_uploadFileSpecificContentType
+
+- Endpoint: `post /type/file/body/request/specific-content-type`
+
+Test File type as request body with specific content type.
+Expected request:
+
+- Content-Type header: image/png
+- Body: binary content matching packages/http-specs/assets/image.png
+
 ### Type_Model_Empty_getEmpty
 
 - Endpoint: `get /type/model/empty/alone`

packages/http-specs/specs/payload/multipart/main.tsp

@@ -608,4 +608,91 @@ namespace FormData {
       ): NoContentResponse;
     }
   }
+
+  @route("/file")
+  namespace File {
+    model FileWithRequiredFilename extends TypeSpec.Http.File<"image/png"> {
+      filename: string;
+    }
+
+    @scenario
+    @scenarioDoc("""
+      Test File type in multipart form data with specific content type.
+      Expected request:
+      ```
+      POST /multipart/form-data/file/specific-content-type HTTP/1.1
+      Content-Type: multipart/form-data; boundary=abcde12345
+
+      --abcde12345
+      Content-Disposition: form-data; name="file"; filename="image.png"
+      Content-Type: image/png
+
+      {…file content of image.png…}
+      --abcde12345--
+      ```
+      """)
+    @post
+    @route("/specific-content-type")
+    op uploadFileSpecificContentType(
+      @header contentType: "multipart/form-data",
+      @multipartBody body: {
+        file: HttpPart<TypeSpec.Http.File<"image/png">>;
+      },
+    ): NoContentResponse;
+
+    @scenario
+    @scenarioDoc("""
+      Test File type in multipart form data with required filename.
+      Expected request:
+      ```
+      POST /multipart/form-data/file/required-filename HTTP/1.1
+      Content-Type: multipart/form-data; boundary=abcde12345
+
+      --abcde12345
+      Content-Disposition: form-data; name="file"; filename="image.png"
+      Content-Type: image/png
+
+      {…file content of image.png…}
+      --abcde12345--
+      ```
+      """)
+    @post
+    @route("/required-filename")
+    op uploadFileRequiredFilename(
+      @header contentType: "multipart/form-data",
+      @multipartBody body: {
+        file: HttpPart<FileWithRequiredFilename>;
+      },
+    ): NoContentResponse;
+
+    @scenario
+    @scenarioDoc("""
+      Test multiple File instances in multipart form data.
+      Expected request:
+      ```
+      POST /multipart/form-data/file/file-array HTTP/1.1
+      Content-Type: multipart/form-data; boundary=abcde12345
+
+      --abcde12345
+      Content-Disposition: form-data; name="files"; filename="image1.png"
+      Content-Type: image/png
+
+      {…file content of image.png…}
+      --abcde12345
+      Content-Disposition: form-data; name="files"; filename="image2.png"
+      Content-Type: image/png
+
+      {…file content of image.png…}
+      --abcde12345--
+      ```
+      """)
+    @post
+    @route("/file-array")
+    op uploadFileArray(
+      @header contentType: "multipart/form-data",
+      @multipartBody body: {
+        files: HttpPart<TypeSpec.Http.File<"image/png">>[];
+      },
+    ): NoContentResponse;
+  }
 }

packages/http-specs/specs/payload/multipart/mockapi.ts

@@ -414,3 +414,92 @@ Scenarios.Payload_MultiPart_FormData_HttpParts_NonString_float = passOnSuccess({
   handler: (req: MockRequest) => createHandler(req, [checkFloat]),
   kind: "MockApiDefinition",
 });
+
+// Helper function to check file in multipart for File type tests
+function checkMultipartFile(
+  req: MockRequest,
+  file: Record<string, any>,
+  expectedContent: Buffer,
+  expectedContentType: string,
+  fieldName: string = "file",
+  expectedFileName?: string,
+) {
+  req.expect.deepEqual(file.fieldname, fieldName);
+  req.expect.deepEqual(file.mimetype, expectedContentType);
+  req.expect.deepEqual(file.buffer, expectedContent);
+  if (expectedFileName) {
+    req.expect.deepEqual(file.originalname, expectedFileName);
+  }
+}
+
+// Multipart File type tests
+Scenarios.Payload_MultiPart_FormData_File_uploadFileSpecificContentType = passOnSuccess({
+  uri: "/multipart/form-data/file/specific-content-type",
+  method: "post",
+  request: {
+    headers: {
+      "content-type": "multipart/form-data",
+    },
+  },
+  response: {
+    status: 204,
+  },
+  handler(req: MockRequest) {
+    if (req.files instanceof Array && req.files.length === 1) {
+      const file = req.files[0];
+      checkMultipartFile(req, file, pngFile, "image/png", "file", "image.png");
+      return { status: 204 };
+    } else {
+      throw new ValidationError("Expected exactly one file", "1 file", req.files);
+    }
+  },
+  kind: "MockApiDefinition",
+});
+
+Scenarios.Payload_MultiPart_FormData_File_uploadFileRequiredFilename = passOnSuccess({
+  uri: "/multipart/form-data/file/required-filename",
+  method: "post",
+  request: {
+    headers: {
+      "content-type": "multipart/form-data",
+    },
+  },
+  response: {
+    status: 204,
+  },
+  handler(req: MockRequest) {
+    if (req.files instanceof Array && req.files.length === 1) {
+      const file = req.files[0];
+      checkMultipartFile(req, file, pngFile, "image/png", "file", "image.png");
+      return { status: 204 };
+    } else {
+      throw new ValidationError("Expected exactly one file", "1 file", req.files);
+    }
+  },
+  kind: "MockApiDefinition",
+});
+
+Scenarios.Payload_MultiPart_FormData_File_uploadFileArray = passOnSuccess({
+  uri: "/multipart/form-data/file/file-array",
+  method: "post",
+  request: {
+    headers: {
+      "content-type": "multipart/form-data",
+    },
+  },
+  response: {
+    status: 204,
+  },
+  handler(req: MockRequest) {
+    if (req.files instanceof Array && req.files.length === 2) {
+      for (const file of req.files) {
+        req.expect.deepEqual(file.fieldname, "files");
+        checkMultipartFile(req, file, pngFile, "image/png", "files");
+      }
+      return { status: 204 };
+    } else {
+      throw new ValidationError("Expected exactly two files", "2 files", req.files);
+    }
+  },
+  kind: "MockApiDefinition",
+});