gzip compressoin test

src/main/java/net/runelite/cache/fs/DataFile.java

@@ -323,15 +323,13 @@ public class DataFile implements Closeable
 				compressedData = data;
 				stream.writeInt(data.length);
 				break;
+			case 1:
+				compressedData = (byte[]) null;
+				break;
 			default:
-				throw new RuntimeException();
-//			case 1:
-//				compressedData = (byte[]) null;
-//				break;
-//			default:
-//				compressedData = GZipCompressor.compress(data);
-//				stream.writeInt(compressedData.length);
-//				stream.writeInt(data.length);
+				compressedData = GZip.compress(data);
+				stream.writeInt(compressedData.length);
+				stream.writeInt(data.length);
 		}
 
 		stream.writeBytes(compressedData);

src/test/java/net/runelite/cache/fs/DataFileTest.java

@@ -50,4 +50,18 @@ public class DataFileTest
 		Assert.assertArrayEquals(b, buf);
 		file.delete();
 	}
+	
+	@Test
+	public void testGZipCompression() throws IOException
+	{
+		try (Store store = new Store(folder.getRoot()))
+		{
+			DataFile df = new DataFile(store, folder.newFile());
+			DataFileWriteResult res = df.write(41, 4, ByteBuffer.wrap("test".getBytes()), 2, 0);
+			DataFileReadResult res2 = df.read(41, 4, res.sector, res.compressedLength);
+			byte[] buf = res2.data;
+			String str = new String(buf);
+			Assert.assertEquals("test", str);
+		}
+	}
 }