Fix incorrect Content-Type inference for POST/PUT/PATCH requests without body

Signed-off-by: banseok1216 <bansuk1216@naver.com>

Author: banseok1216

.DS_Store

@@ -178,7 +178,7 @@ private void writeMultipartEnd(PrintWriter writer) {
 
 	private boolean requiresFormEncodingContentTypeHeader(OperationRequest request) {
 		return request.getHeaders().get(HttpHeaders.CONTENT_TYPE) == null && isPutPostOrPatch(request)
-				&& !includeParametersInUri(request);
+				&& request.getContent().length > 0 && !includeParametersInUri(request);
 	}
 
 	private Map<String, String> header(String name, String value) {

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

@@ -244,6 +244,14 @@ void deleteWithQueryString(OperationBuilder operationBuilder, AssertableSnippets
 			.isHttpRequest((request) -> request.delete("/foo?a=alpha&b=bravo").header("Host", "localhost"));
 	}
 
+	@RenderedSnippetTest
+	void postRequestWithNoContentTypeAndNoBodyDoesNotIncludeContentTypeHeader(OperationBuilder operationBuilder,
+			AssertableSnippets snippets) throws IOException {
+		new HttpRequestSnippet().document(operationBuilder.request("http://localhost/foo").method("POST").build());
+		assertThat(snippets.httpRequest())
+			.isHttpRequest((request) -> request.post("/foo").header(HttpHeaders.HOST, "localhost"));
+	}
+
 	private String createPart(String content) {
 		return this.createPart(content, true);
 	}