Fix buffer leak in test which was introduced while implement ZLIB_OR_NONE support. Related to [#2269]

codec/src/main/java/io/netty/handler/codec/compression/JdkZlibDecoder.java

@@ -385,7 +385,7 @@ public class JdkZlibDecoder extends ZlibDecoder {
      * You can lookup the details in the ZLIB RFC:
      * <a href="http://tools.ietf.org/html/rfc1950#section-2.2">RFC 1950</a>.
      */
-    private boolean looksLikeZlib(short cmf_flg) {
+    private static boolean looksLikeZlib(short cmf_flg) {
         return (cmf_flg & 0x7800) == 0x7800 &&
                 cmf_flg % 31 == 0;
     }

codec/src/test/java/io/netty/handler/codec/compression/ZlibTest.java

@@ -48,6 +48,7 @@ public abstract class ZlibTest {
         ByteBuf deflatedData = Unpooled.wrappedBuffer(gzip("message"));
 
         EmbeddedChannel chDecoderGZip = new EmbeddedChannel(createDecoder(ZlibWrapper.GZIP));
+        try {
             chDecoderGZip.writeInbound(deflatedData.copy());
             assertTrue(chDecoderGZip.finish());
             ByteBuf buf = (ByteBuf) chDecoderGZip.readInbound();
@@ -56,15 +57,20 @@ public abstract class ZlibTest {
             data.release();
             deflatedData.release();
             buf.release();
+        } finally {
+            // close channel to prevent any leak even on exception
+            chDecoderGZip.close();
+        }
     }
 
     private void testCompress0(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper, ByteBuf data) throws Exception {
         EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper));
+        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
 
+        try {
             chEncoder.writeOutbound(data.copy());
             chEncoder.flush();
 
-        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
             for (;;) {
                 ByteBuf deflatedData = (ByteBuf) chEncoder.readOutbound();
                 if (deflatedData == null) {
@@ -104,15 +110,20 @@ public abstract class ZlibTest {
             assertFalse(chDecoderZlib.finish());
 
             data.release();
+        } finally {
+            // close channels in all cases to guard against leak when exception was thrown
+            chEncoder.close();
+            chDecoderZlib.close();
+        }
     }
 
     private void testCompressNone(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {
         EmbeddedChannel chEncoder = new EmbeddedChannel(createEncoder(encoderWrapper));
-
+        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
+        try {
             // Closing an encoder channel without writing anything should generate both header and footer.
             assertTrue(chEncoder.finish());
 
-        EmbeddedChannel chDecoderZlib = new EmbeddedChannel(createDecoder(decoderWrapper));
             for (;;) {
                 ByteBuf deflatedData = (ByteBuf) chEncoder.readOutbound();
                 if (deflatedData == null) {
@@ -122,6 +133,7 @@ public abstract class ZlibTest {
             }
 
             // Decoder should not generate anything at all.
+            boolean decoded = false;
             for (;;) {
                 ByteBuf buf = (ByteBuf) chDecoderZlib.readInbound();
                 if (buf == null) {
@@ -129,10 +141,16 @@ public abstract class ZlibTest {
                 }
 
                 buf.release();
-            fail("should decode nothing");
+                decoded = true;
             }
+            assertFalse("should decode nothing", decoded);
 
             assertFalse(chDecoderZlib.finish());
+        } finally {
+            // close channels in all cases to guard against leak when exception was thrown
+            chEncoder.close();
+            chDecoderZlib.close();
+        }
     }
 
     private void testCompressSmall(ZlibWrapper encoderWrapper, ZlibWrapper decoderWrapper) throws Exception {