Support Filters/Servlet invocation in MockFilterChain

This commit adds the ability to allow the MockFilterChain to invoke
a List of Filter's and/or a Servlet.

Issue: SPR-9745

spring-test/src/test/java/org/springframework/mock/web/MockFilterChainTests.java

@@ -0,0 +1,166 @@
+/*
+ * Copyright 2002-2012 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.mock.web;
+
+import static org.easymock.EasyMock.*;
+import static org.hamcrest.Matchers.is;
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+
+import javax.servlet.Filter;
+import javax.servlet.FilterChain;
+import javax.servlet.FilterConfig;
+import javax.servlet.Servlet;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Test fixture for {@link MockFilterChain}.
+ *
+ * @author Rob Winch
+ */
+public class MockFilterChainTests {
+
+	private ServletRequest request;
+
+	private ServletResponse response;
+
+	@Before
+	public void setup() {
+		this.request = new MockHttpServletRequest();
+		this.response = new MockHttpServletResponse();
+	}
+
+	@Test(expected=IllegalArgumentException.class)
+	public void constructorNullServlet() {
+		new MockFilterChain((Servlet) null);
+	}
+
+	@Test(expected=IllegalArgumentException.class)
+	public void constructorNullFilter() {
+		new MockFilterChain(createMock(Servlet.class), (Filter) null);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void doFilterNullRequest() throws Exception {
+		MockFilterChain chain = new MockFilterChain();
+		chain.doFilter(null, this.response);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void doFilterNullResponse() throws Exception {
+		MockFilterChain chain = new MockFilterChain();
+		chain.doFilter(this.request, null);
+	}
+
+	@Test
+	public void doFilterEmptyChain() throws Exception {
+		MockFilterChain chain = new MockFilterChain();
+		chain.doFilter(this.request, this.response);
+
+		assertThat(chain.getRequest(), is(request));
+		assertThat(chain.getResponse(), is(response));
+
+		try {
+			chain.doFilter(this.request, this.response);
+			fail("Expected Exception");
+		}
+		catch(IllegalStateException ex) {
+			assertEquals("This FilterChain has already been called!", ex.getMessage());
+		}
+	}
+
+	@Test
+	public void doFilterWithServlet() throws Exception {
+		Servlet servlet = createMock(Servlet.class);
+
+		MockFilterChain chain = new MockFilterChain(servlet);
+		servlet.service(this.request, this.response);
+		replay(servlet);
+
+		chain.doFilter(this.request, this.response);
+
+		verify(servlet);
+
+		try {
+			chain.doFilter(this.request, this.response);
+			fail("Expected Exception");
+		}
+		catch(IllegalStateException ex) {
+			assertEquals("This FilterChain has already been called!", ex.getMessage());
+		}
+	}
+
+	@Test
+	public void doFilterWithServletAndFilters() throws Exception {
+		Servlet servlet = createMock(Servlet.class);
+		servlet.service(this.request, this.response);
+		replay(servlet);
+
+		MockFilter filter2 = new MockFilter(servlet);
+		MockFilter filter1 = new MockFilter(null);
+		MockFilterChain chain = new MockFilterChain(servlet, filter1, filter2);
+
+		chain.doFilter(this.request, this.response);
+
+		assertTrue(filter1.invoked);
+		assertTrue(filter2.invoked);
+
+		verify(servlet);
+
+		try {
+			chain.doFilter(this.request, this.response);
+			fail("Expected Exception");
+		}
+		catch(IllegalStateException ex) {
+			assertEquals("This FilterChain has already been called!", ex.getMessage());
+		}
+	}
+
+
+	private static class MockFilter implements Filter {
+
+		private final Servlet servlet;
+
+		private boolean invoked;
+
+		public MockFilter(Servlet servlet) {
+			this.servlet = servlet;
+		}
+
+		public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain)
+				throws IOException, ServletException {
+
+			this.invoked = true;
+
+			if (this.servlet != null) {
+				this.servlet.service(request, response);
+			}
+			else {
+				chain.doFilter(request, response);
+			}
+		}
+
+		public void init(FilterConfig filterConfig) throws ServletException {
+		}
+
+		public void destroy() {
+		}
+	}
+
+}