Reduce duplication by introducing RestDocumentationHandler

Previously, logic for creating an Operation, determining the snippets
to call, and calling them was duplicated in both the MockMvc and
REST Assured modules. This commit introduces a new core class,
RestDocumentationHandler, that now does the bulk of the work in a
reusable manner. The MockMvc and REST Assured modules have been
updated to delegate to RestDocumentationHandler.

Closes gh-194

spring-restdocs-core/src/test/java/org/springframework/restdocs/RestDocumentationHandlerTests.java

@@ -0,0 +1,130 @@
+/*
+ * Copyright 2012-2016 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 org.springframework.restdocs;
+
+import java.io.IOException;
+import java.net.URI;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.springframework.http.HttpHeaders;
+import org.springframework.restdocs.config.SnippetConfigurer;
+import org.springframework.restdocs.operation.Operation;
+import org.springframework.restdocs.operation.OperationRequest;
+import org.springframework.restdocs.operation.OperationRequestFactory;
+import org.springframework.restdocs.operation.OperationResponse;
+import org.springframework.restdocs.operation.OperationResponseFactory;
+import org.springframework.restdocs.operation.RequestConverter;
+import org.springframework.restdocs.operation.ResponseConverter;
+import org.springframework.restdocs.snippet.Snippet;
+
+import static org.hamcrest.CoreMatchers.equalTo;
+import static org.hamcrest.CoreMatchers.is;
+import static org.junit.Assert.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+/**
+ * Tests for {@link RestDocumentationHandler}.
+ *
+ * @author Andy Wilkinson
+ */
+public class RestDocumentationHandlerTests {
+
+	@SuppressWarnings("unchecked")
+	private final RequestConverter<Object> requestConverter = mock(RequestConverter.class);
+
+	@SuppressWarnings("unchecked")
+	private final ResponseConverter<Object> responseConverter = mock(ResponseConverter.class);
+
+	private final Object request = new Object();
+
+	private final Object response = new Object();
+
+	private final OperationRequest operationRequest = new OperationRequestFactory()
+			.create(URI.create("http://localhost:8080"), null, null, new HttpHeaders(),
+					null, null);
+
+	private final OperationResponse operationResponse = new OperationResponseFactory()
+			.create(null, null, null);
+
+	private final Snippet snippet = mock(Snippet.class);
+
+	@Test
+	public void basicHandling() throws IOException {
+		given(this.requestConverter.convert(this.request)).willReturn(
+				this.operationRequest);
+		given(this.responseConverter.convert(this.response)).willReturn(
+				this.operationResponse);
+		HashMap<String, Object> configuration = new HashMap<>();
+		new RestDocumentationHandler<>("id", this.requestConverter,
+				this.responseConverter, this.snippet).handle(this.request, this.response,
+				configuration);
+		verifySnippetInvocation(this.snippet, configuration);
+	}
+
+	@Test
+	public void defaultSnippetsAreCalled() throws IOException {
+		given(this.requestConverter.convert(this.request)).willReturn(
+				this.operationRequest);
+		given(this.responseConverter.convert(this.response)).willReturn(
+				this.operationResponse);
+		HashMap<String, Object> configuration = new HashMap<>();
+		Snippet defaultSnippet1 = mock(Snippet.class);
+		Snippet defaultSnippet2 = mock(Snippet.class);
+		configuration.put(SnippetConfigurer.ATTRIBUTE_DEFAULT_SNIPPETS,
+				Arrays.asList(defaultSnippet1, defaultSnippet2));
+		new RestDocumentationHandler<>("id", this.requestConverter,
+				this.responseConverter, this.snippet).handle(this.request, this.response,
+				configuration);
+		verifySnippetInvocation(this.snippet, configuration);
+		verifySnippetInvocation(defaultSnippet1, configuration);
+		verifySnippetInvocation(defaultSnippet2, configuration);
+	}
+
+	@Test
+	public void additionalSnippetsAreCalled() throws IOException {
+		given(this.requestConverter.convert(this.request)).willReturn(
+				this.operationRequest);
+		given(this.responseConverter.convert(this.response)).willReturn(
+				this.operationResponse);
+		Snippet additionalSnippet1 = mock(Snippet.class);
+		Snippet additionalSnippet2 = mock(Snippet.class);
+		RestDocumentationHandler<Object, Object> handler = new RestDocumentationHandler<>(
+				"id", this.requestConverter, this.responseConverter, this.snippet);
+		handler.addSnippets(additionalSnippet1, additionalSnippet2);
+		HashMap<String, Object> configuration = new HashMap<>();
+		handler.handle(this.request, this.response, configuration);
+		verifySnippetInvocation(this.snippet, configuration);
+		verifySnippetInvocation(additionalSnippet1, configuration);
+		verifySnippetInvocation(additionalSnippet2, configuration);
+	}
+
+	private void verifySnippetInvocation(Snippet snippet, Map<String, Object> attributes)
+			throws IOException {
+		ArgumentCaptor<Operation> operation = ArgumentCaptor.forClass(Operation.class);
+		verify(snippet).document(operation.capture());
+		assertThat(this.operationRequest, is(equalTo(operation.getValue().getRequest())));
+		assertThat(this.operationResponse,
+				is(equalTo(operation.getValue().getResponse())));
+		assertThat(attributes, is(equalTo(operation.getValue().getAttributes())));
+	}
+}