Add support for using WebFlux's WebTestClient to document an API

Closes gh-384

docs/src/test/java/com/example/webtestclient/HttpHeaders.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright 2014-2017 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.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.example.webtestclient;
+
+import org.springframework.test.web.reactive.server.WebTestClient;
+
+import static org.springframework.restdocs.headers.HeaderDocumentation.headerWithName;
+import static org.springframework.restdocs.headers.HeaderDocumentation.requestHeaders;
+import static org.springframework.restdocs.headers.HeaderDocumentation.responseHeaders;
+import static org.springframework.restdocs.webtestclient.WebTestClientRestDocumentation.document;
+
+public class HttpHeaders {
+
+	// @formatter:off
+
+	private WebTestClient webTestClient;
+
+	public void headers() throws Exception {
+		// tag::headers[]
+		this.webTestClient
+			.get().uri("/people").header("Authorization", "Basic dXNlcjpzZWNyZXQ=") // <1>
+			.exchange().expectStatus().isOk().expectBody()
+			.consumeWith(document("headers",
+				requestHeaders( // <2>
+					headerWithName("Authorization").description("Basic auth credentials")), // <3>
+				responseHeaders( // <4>
+					headerWithName("X-RateLimit-Limit")
+						.description("The total number of requests permitted per period"),
+					headerWithName("X-RateLimit-Remaining")
+						.description("Remaining requests permitted in current period"),
+					headerWithName("X-RateLimit-Reset")
+						.description("Time at which the rate limit period will reset"))));
+		// end::headers[]
+	}
+}