public virtual void TestCorruptedIFile() { int fetcher = 7; Path onDiskMapOutputPath = new Path(name.GetMethodName() + "/foo"); Path shuffledToDisk = OnDiskMapOutput.GetTempPath(onDiskMapOutputPath, fetcher); fs = FileSystem.GetLocal(job).GetRaw(); MapOutputFile mof = Org.Mockito.Mockito.Mock <MapOutputFile>(); OnDiskMapOutput <Text, Text> odmo = new OnDiskMapOutput <Text, Text>(map1ID, id, mm , 100L, job, mof, fetcher, true, fs, onDiskMapOutputPath); string mapData = "MAPDATA12345678901234567890"; ShuffleHeader header = new ShuffleHeader(map1ID.ToString(), 14, 10, 1); ByteArrayOutputStream bout = new ByteArrayOutputStream(); DataOutputStream dos = new DataOutputStream(bout); IFileOutputStream ios = new IFileOutputStream(dos); header.Write(dos); int headerSize = dos.Size(); try { ios.Write(Sharpen.Runtime.GetBytesForString(mapData)); } finally { ios.Close(); } int dataSize = bout.Size() - headerSize; // Ensure that the OnDiskMapOutput shuffler can successfully read the data. MapHost host = new MapHost("TestHost", "http://test/url"); ByteArrayInputStream bin = new ByteArrayInputStream(bout.ToByteArray()); try { // Read past the shuffle header. bin.Read(new byte[headerSize], 0, headerSize); odmo.Shuffle(host, bin, dataSize, dataSize, metrics, Reporter.Null); } finally { bin.Close(); } // Now corrupt the IFile data. byte[] corrupted = bout.ToByteArray(); corrupted[headerSize + (dataSize / 2)] = unchecked ((int)(0x0)); try { bin = new ByteArrayInputStream(corrupted); // Read past the shuffle header. bin.Read(new byte[headerSize], 0, headerSize); odmo.Shuffle(host, bin, dataSize, dataSize, metrics, Reporter.Null); NUnit.Framework.Assert.Fail("OnDiskMapOutput.shuffle didn't detect the corrupted map partition file" ); } catch (ChecksumException e) { Log.Info("The expected checksum exception was thrown.", e); } finally { bin.Close(); } // Ensure that the shuffled file can be read. IFileInputStream iFin = new IFileInputStream(fs.Open(shuffledToDisk), dataSize, job ); try { iFin.Read(new byte[dataSize], 0, dataSize); } finally { iFin.Close(); } }