Fix GzipEncodingEnforcingFilter getHeaders always with a const value

eureka-core/src/main/java/com/netflix/eureka/GzipEncodingEnforcingFilter.java

@@ -60,7 +60,7 @@ public Enumeration<String> getHeaders(String name) {
                 if (HttpHeaders.ACCEPT_ENCODING.equals(name)) {
                     return new EnumWrapper<String>("gzip");
                 }
-                return new EnumWrapper<String>(super.getHeaders(name), HttpHeaders.ACCEPT_ENCODING);
+                return super.getHeaders(name);
             }
 
             @Override

eureka-core/src/test/java/com/netflix/eureka/GzipEncodingEnforcingFilterTest.java

@@ -0,0 +1,125 @@
+/*
+ * Copyright 2014 Netflix, Inc.
+ *
+ * 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.netflix.eureka;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.mockito.runners.MockitoJUnitRunner;
+
+import javax.servlet.FilterChain;
+import javax.servlet.ServletException;
+import javax.servlet.ServletRequest;
+import javax.servlet.ServletResponse;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+
+import java.io.IOException;
+import java.util.Enumeration;
+
+import static org.junit.Assert.assertEquals;
+import static org.mockito.Mockito.*;
+
+/**
+ * @author Kebe Liu
+ */
+@RunWith(MockitoJUnitRunner.class)
+public class GzipEncodingEnforcingFilterTest {
+
+    private static final String ACCEPT_ENCODING_HEADER = "Accept-Encoding";
+    @Mock
+    private HttpServletRequest request;
+
+    private HttpServletRequest filteredRequest;
+
+    @Mock
+    private HttpServletResponse response;
+
+    @Mock
+    private FilterChain filterChain;
+
+    private GzipEncodingEnforcingFilter filter;
+
+    @Before
+    public void setUp() throws Exception {
+        filter = new GzipEncodingEnforcingFilter();
+        filterChain = new FilterChain() {
+            @Override
+            public void doFilter(ServletRequest req, ServletResponse response) throws IOException, ServletException {
+                filteredRequest = (HttpServletRequest) req;
+            }
+        };
+    }
+
+    @Test
+    public void testAlreadyGzip() throws Exception {
+        gzipRequest();
+        filter.doFilter(request, response, filterChain);
+        Enumeration values = filteredRequest.getHeaders(ACCEPT_ENCODING_HEADER);
+        assertEquals("Expected Accept-Encoding null", null, values);
+    }
+
+    @Test
+    public void testForceGzip() throws Exception {
+        noneGzipRequest();
+        filter.doFilter(request, response, filterChain);
+        String res = "";
+        Enumeration values = filteredRequest.getHeaders(ACCEPT_ENCODING_HEADER);
+        while (values.hasMoreElements()) {
+            res = res + values.nextElement() + "\n";
+        }
+        assertEquals("Expected Accept-Encoding gzip", "gzip\n", res);
+    }
+
+    @Test
+    public void testForceGzipOtherHeader() throws Exception {
+        noneGzipRequest();
+        when(request.getHeader("Test")).thenReturn("ok");
+        when(request.getHeaders("Test")).thenReturn(new Enumeration() {
+            private int c = 0;
+
+            @Override
+            public boolean hasMoreElements() {
+                return c == 0;
+            }
+
+            @Override
+            public Object nextElement() {
+                c++;
+                return "ok";
+            }
+        });
+        filter.doFilter(request, response, filterChain);
+        String res = "";
+        Enumeration values = filteredRequest.getHeaders("Test");
+        while (values.hasMoreElements()) {
+            res = res + values.nextElement() + "\n";
+        }
+        assertEquals("Expected Test ok", "ok\n", res);
+    }
+
+    private void gzipRequest() {
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getHeader(ACCEPT_ENCODING_HEADER)).thenReturn("gzip");
+    }
+
+    private void noneGzipRequest() {
+        when(request.getMethod()).thenReturn("GET");
+        when(request.getHeader(ACCEPT_ENCODING_HEADER)).thenReturn(null);
+    }
+}