Fix HTTP request snippet's body for multipart PATCH requests

Closes gh-933

Author: wilkinsona

spring-restdocs-core/src/main/java/org/springframework/restdocs/http/HttpRequestSnippet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -120,16 +120,17 @@ private String getRequestBody(OperationRequest request) {
 		if (StringUtils.hasText(content)) {
 			writer.printf("%n%s", content);
 		}
-		else if (isPutOrPost(request)) {
+		else if (isPutPostOrPatch(request)) {
 			if (!request.getParts().isEmpty()) {
 				writeParts(request, writer);
 			}
 		}
 		return httpRequest.toString();
 	}
 
-	private boolean isPutOrPost(OperationRequest request) {
-		return HttpMethod.PUT.equals(request.getMethod()) || HttpMethod.POST.equals(request.getMethod());
+	private boolean isPutPostOrPatch(OperationRequest request) {
+		return HttpMethod.PUT.equals(request.getMethod()) || HttpMethod.POST.equals(request.getMethod())
+				|| HttpMethod.PATCH.equals(request.getMethod());
 	}
 
 	private void writeParts(OperationRequest request, PrintWriter writer) {
@@ -169,7 +170,7 @@ private void writeMultipartEnd(PrintWriter writer) {
 	}
 
 	private boolean requiresFormEncodingContentTypeHeader(OperationRequest request) {
-		return request.getHeaders().get(HttpHeaders.CONTENT_TYPE) == null && isPutOrPost(request)
+		return request.getHeaders().get(HttpHeaders.CONTENT_TYPE) == null && isPutPostOrPatch(request)
 				&& !includeParametersInUri(request);
 	}
 

spring-restdocs-core/src/test/java/org/springframework/restdocs/http/HttpRequestSnippetTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2014-2023 the original author or authors.
+ * Copyright 2014-2024 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -165,6 +165,36 @@ public void multipartPost() throws IOException {
 			.content(expectedContent));
 	}
 
+	@Test
+	public void multipartPut() throws IOException {
+		new HttpRequestSnippet().document(this.operationBuilder.request("http://localhost/upload")
+			.method("PUT")
+			.header(HttpHeaders.CONTENT_TYPE, MediaType.MULTIPART_FORM_DATA_VALUE)
+			.part("image", "<< data >>".getBytes())
+			.build());
+		String expectedContent = createPart(
+				String.format("Content-Disposition: " + "form-data; " + "name=image%n%n<< data >>"));
+		assertThat(this.generatedSnippets.httpRequest()).is(httpRequest(RequestMethod.PUT, "/upload")
+			.header("Content-Type", "multipart/form-data; boundary=" + BOUNDARY)
+			.header(HttpHeaders.HOST, "localhost")
+			.content(expectedContent));
+	}
+
+	@Test
+	public void multipartPatch() throws IOException {
+		new HttpRequestSnippet().document(this.operationBuilder.request("http://localhost/upload")
+			.method("PATCH")
+			.header(HttpHeaders.CONTENT_TYPE, MediaType.MULTIPART_FORM_DATA_VALUE)
+			.part("image", "<< data >>".getBytes())
+			.build());
+		String expectedContent = createPart(
+				String.format("Content-Disposition: " + "form-data; " + "name=image%n%n<< data >>"));
+		assertThat(this.generatedSnippets.httpRequest()).is(httpRequest(RequestMethod.PATCH, "/upload")
+			.header("Content-Type", "multipart/form-data; boundary=" + BOUNDARY)
+			.header(HttpHeaders.HOST, "localhost")
+			.content(expectedContent));
+	}
+
 	@Test
 	public void multipartPostWithFilename() throws IOException {
 		new HttpRequestSnippet().document(this.operationBuilder.request("http://localhost/upload")