MockMvc supports FilterRegistration filter init

Closes gh-33252

spring-test/src/main/java/org/springframework/mock/web/MockFilterRegistration.java

@@ -0,0 +1,129 @@
+/*
+ * Copyright 2002-2024 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://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 java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.LinkedHashSet;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import jakarta.servlet.DispatcherType;
+import jakarta.servlet.FilterRegistration;
+
+import org.springframework.lang.Nullable;
+
+/**
+ * Mock implementation of {@link FilterRegistration}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 6.2
+ */
+public class MockFilterRegistration implements FilterRegistration {
+
+	private final String name;
+
+	private final String className;
+
+	private final Map<String, String> initParameters = new LinkedHashMap<>();
+
+	private final List<String> servletNames = new ArrayList<>();
+
+	private final List<String> urlPatterns = new ArrayList<>();
+
+
+	public MockFilterRegistration(String className) {
+		this(className, "");
+	}
+
+	public MockFilterRegistration(String className, String name) {
+		this.name = name;
+		this.className = className;
+	}
+
+
+	@Override
+	public String getName() {
+		return this.name;
+	}
+
+	@Nullable
+	@Override
+	public String getClassName() {
+		return this.className;
+	}
+
+	@Override
+	public boolean setInitParameter(String name, String value) {
+		return (this.initParameters.putIfAbsent(name, value) != null);
+	}
+
+	@Nullable
+	@Override
+	public String getInitParameter(String name) {
+		return this.initParameters.get(name);
+	}
+
+	@Override
+	public Set<String> setInitParameters(Map<String, String> initParameters) {
+		Set<String> existingParameterNames = new LinkedHashSet<>();
+		for (Map.Entry<String, String> entry : initParameters.entrySet()) {
+			if (this.initParameters.get(entry.getKey()) != null) {
+				existingParameterNames.add(entry.getKey());
+			}
+		}
+		if (existingParameterNames.isEmpty()) {
+			this.initParameters.putAll(initParameters);
+		}
+		return existingParameterNames;
+	}
+
+	@Override
+	public Map<String, String> getInitParameters() {
+		return Collections.unmodifiableMap(this.initParameters);
+	}
+
+	@Override
+	public void addMappingForServletNames(
+			EnumSet<DispatcherType> dispatcherTypes, boolean isMatchAfter, String... servletNames) {
+
+		this.servletNames.addAll(Arrays.asList(servletNames));
+	}
+
+	@Override
+	public Collection<String> getServletNameMappings() {
+		return Collections.unmodifiableCollection(this.servletNames);
+	}
+
+	@Override
+	public void addMappingForUrlPatterns(
+			EnumSet<DispatcherType> dispatcherTypes, boolean isMatchAfter, String... urlPatterns) {
+
+		this.urlPatterns.addAll(Arrays.asList(urlPatterns));
+	}
+
+	@Override
+	public Collection<String> getUrlPatternMappings() {
+		return Collections.unmodifiableCollection(this.urlPatterns);
+	}
+
+}

spring-test/src/main/java/org/springframework/mock/web/MockServletContext.java

@@ -145,6 +145,8 @@ public class MockServletContext implements ServletContext {
 	@Nullable
 	private String responseCharacterEncoding;
 
+	private final Map<String, FilterRegistration> filterRegistrations = new LinkedHashMap<>();
+
 	private final Map<String, MediaType> mimeTypes = new LinkedHashMap<>();
 
 
@@ -604,6 +606,25 @@ public class MockServletContext implements ServletContext {
 		return this.responseCharacterEncoding;
 	}
 
+	/**
+	 * Add a {@link FilterRegistration}.
+	 * @since 6.2
+	 */
+	public void addFilterRegistration(FilterRegistration registration) {
+		this.filterRegistrations.put(registration.getName(), registration);
+	}
+
+	@Override
+	@Nullable
+	public FilterRegistration getFilterRegistration(String filterName) {
+		return this.filterRegistrations.get(filterName);
+	}
+
+	@Override
+	public Map<String, ? extends FilterRegistration> getFilterRegistrations() {
+		return Collections.unmodifiableMap(this.filterRegistrations);
+	}
+
 
 	//---------------------------------------------------------------------
 	// Unsupported Servlet 3.0 registration methods
@@ -678,25 +699,6 @@ public class MockServletContext implements ServletContext {
 		throw new UnsupportedOperationException();
 	}
 
-	/**
-	 * This method always returns {@code null}.
-	 * @see jakarta.servlet.ServletContext#getFilterRegistration(java.lang.String)
-	 */
-	@Override
-	@Nullable
-	public FilterRegistration getFilterRegistration(String filterName) {
-		return null;
-	}
-
-	/**
-	 * This method always returns an {@linkplain Collections#emptyMap empty map}.
-	 * @see jakarta.servlet.ServletContext#getFilterRegistrations()
-	 */
-	@Override
-	public Map<String, ? extends FilterRegistration> getFilterRegistrations() {
-		return Collections.emptyMap();
-	}
-
 	@Override
 	public void addListener(Class<? extends EventListener> listenerClass) {
 		throw new UnsupportedOperationException();

spring-test/src/main/java/org/springframework/test/web/servlet/setup/MockMvcFilterDecorator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2023 the original author or authors.
+ * Copyright 2002-2024 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.
@@ -35,6 +35,8 @@ import jakarta.servlet.http.HttpServletRequest;
 
 import org.springframework.lang.Nullable;
 import org.springframework.mock.web.MockFilterConfig;
+import org.springframework.mock.web.MockFilterRegistration;
+import org.springframework.mock.web.MockServletContext;
 import org.springframework.util.Assert;
 import org.springframework.web.util.UrlPathHelper;
 
@@ -98,17 +100,27 @@ final class MockMvcFilterDecorator implements Filter {
 		Assert.notNull(delegate, "filter cannot be null");
 		Assert.notNull(urlPatterns, "urlPatterns cannot be null");
 		this.delegate = delegate;
-		this.filterConfigInitializer = getFilterConfigInitializer(filterName, initParams);
+		this.filterConfigInitializer = getFilterConfigInitializer(delegate, filterName, initParams);
 		this.dispatcherTypes = dispatcherTypes;
 		this.hasPatterns = initPatterns(urlPatterns);
 	}
 
 	private static Function<ServletContext, FilterConfig> getFilterConfigInitializer(
-			@Nullable String filterName, @Nullable Map<String, String> initParams) {
+			Filter delegate, @Nullable String filterName, @Nullable Map<String, String> initParams) {
+
+		String className = delegate.getClass().getName();
 
 		return servletContext -> {
-			MockFilterConfig filterConfig = (filterName != null ?
-					new MockFilterConfig(servletContext, filterName) : new MockFilterConfig(servletContext));
+			MockServletContext mockServletContext = (MockServletContext) servletContext;
+			MockFilterConfig filterConfig;
+			if (filterName != null) {
+				filterConfig = new MockFilterConfig(servletContext, filterName);
+				mockServletContext.addFilterRegistration(new MockFilterRegistration(className, filterName));
+			}
+			else {
+				filterConfig = new MockFilterConfig(servletContext);
+				mockServletContext.addFilterRegistration(new MockFilterRegistration(className));
+			}
 			if (initParams != null) {
 				initParams.forEach(filterConfig::addInitParameter);
 			}