Unit tests for IncomingErrorCorrectionLayerImpl.

components/net/sf/briar/transport/IncomingErrorCorrectionLayerImpl.java

@@ -46,7 +46,7 @@ class IncomingErrorCorrectionLayerImpl implements IncomingErrorCorrectionLayer {
 				if(window.contains(frameNumber)) break;
 				if(window.isTooHigh(frameNumber)) countDiscard(frameNumber);
 			}
-			// Add the segment to its segment set, or create one if necessary
+			// Add the segment to its set, creating a set if necessary
 			Segment[] set = segmentSets.get(frameNumber);
 			if(set == null) {
 				set = new Segment[n];
@@ -64,4 +64,14 @@ class IncomingErrorCorrectionLayerImpl implements IncomingErrorCorrectionLayer {
 		else if(count == n - k) throw new FormatException();
 		else discardCounts.put(frameNumber, count + 1);
 	}
+
+	// Only for testing
+	Map<Long, Segment[]> getSegmentSets() {
+		return segmentSets;
+	}
+
+	// Only for testing
+	Map<Long, Integer> getDiscardCounts() {
+		return discardCounts;
+	}
 }

test/build.xml

@@ -58,6 +58,7 @@
 			<test name='net.sf.briar.transport.FrameReadWriteTest'/>
 			<test name='net.sf.briar.transport.FrameWindowImplTest'/>
 			<test name='net.sf.briar.transport.IncomingEncryptionLayerImplTest'/>
+			<test name='net.sf.briar.transport.IncomingErrorCorrectionLayerImplTest'/>
 			<test name='net.sf.briar.transport.IncomingSegmentedEncryptionLayerTest'/>
 			<test name='net.sf.briar.transport.OutgoingEncryptionLayerImplTest'/>
 			<test name='net.sf.briar.transport.OutgoingSegmentedEncryptionLayerTest'/>

test/net/sf/briar/transport/IncomingErrorCorrectionLayerImplTest.java

+package net.sf.briar.transport;
+
+import java.io.IOException;
+import java.util.LinkedList;
+import java.util.Map;
+
+import net.sf.briar.BriarTestCase;
+import net.sf.briar.api.FormatException;
+import net.sf.briar.api.transport.Segment;
+
+import org.jmock.Expectations;
+import org.jmock.Mockery;
+import org.junit.Test;
+
+public class IncomingErrorCorrectionLayerImplTest extends BriarTestCase {
+
+	@Test
+	public void testDiscardedSegmentsAreCounted() throws Exception {
+		LinkedList<Long> segmentNumbers = new LinkedList<Long>();
+		segmentNumbers.add(123L); // 123 / 3 = frame number 41
+		segmentNumbers.add(456L); // 456 / 3 = frame number 152
+		segmentNumbers.add(0L); // 0 / 3 = frame number 0
+		IncomingEncryptionLayer in = new TestIncomingEncryptionLayer(
+				segmentNumbers, 1234);
+		Mockery context = new Mockery();
+		final ErasureDecoder decoder = context.mock(ErasureDecoder.class);
+		final FrameWindow window = context.mock(FrameWindow.class);
+		context.checking(new Expectations() {{
+			// First segment
+			one(window).contains(41L);
+			will(returnValue(false));
+			one(window).isTooHigh(41L);
+			will(returnValue(true));
+			// Second segment
+			one(window).contains(152L);
+			will(returnValue(false));
+			one(window).isTooHigh(152L);
+			will(returnValue(true));
+			// Third segment
+			one(window).contains(0L);
+			will(returnValue(true));
+			one(decoder).decodeFrame(with(any(Frame.class)),
+					with(any(Segment[].class)));
+			will(returnValue(false));
+		}});
+
+		IncomingErrorCorrectionLayerImpl err =
+			new IncomingErrorCorrectionLayerImpl(in, decoder, 3, 2);
+		Frame f = new Frame();
+		assertFalse(err.readFrame(f, window));
+		Map<Long, Integer> discardCounts = err.getDiscardCounts();
+		assertEquals(2, discardCounts.size());
+		assertEquals(Integer.valueOf(1), discardCounts.get(41L));
+		assertEquals(Integer.valueOf(1), discardCounts.get(152L));
+
+		context.assertIsSatisfied();
+	}
+
+	@Test
+	public void testTooManyDiscardedSegmentsCauseException() throws Exception {
+		LinkedList<Long> segmentNumbers = new LinkedList<Long>();
+		segmentNumbers.add(123L); // 123 / 3 = frame number 41
+		segmentNumbers.add(124L); // 124 / 3 = frame number 41
+		IncomingEncryptionLayer in = new TestIncomingEncryptionLayer(
+				segmentNumbers, 1234);
+		Mockery context = new Mockery();
+		final ErasureDecoder decoder = context.mock(ErasureDecoder.class);
+		final FrameWindow window = context.mock(FrameWindow.class);
+		context.checking(new Expectations() {{
+			// First segment
+			one(window).contains(41L);
+			will(returnValue(false));
+			one(window).isTooHigh(41L);
+			will(returnValue(true));
+			// Second segment
+			one(window).contains(41L);
+			will(returnValue(false));
+			one(window).isTooHigh(41L);
+			will(returnValue(true));
+		}});
+		IncomingErrorCorrectionLayerImpl err =
+			new IncomingErrorCorrectionLayerImpl(in, decoder, 3, 2);
+		Frame f = new Frame();
+		try {
+			err.readFrame(f, window);
+			fail();
+		} catch(FormatException expected) {}
+
+		context.assertIsSatisfied();
+	}
+
+	@Test
+	public void testSetsAndDiscardedSegmentsAreFreed() throws Exception {
+		LinkedList<Long> segmentNumbers = new LinkedList<Long>();
+		segmentNumbers.add(96L); // 96 / 3 = frame number 32
+		segmentNumbers.add(0L); // 0 / 3 = frame number 0
+		segmentNumbers.add(1L); // 1 / 3 = frame number 0
+		IncomingEncryptionLayer in = new TestIncomingEncryptionLayer(
+				segmentNumbers, 1234);
+		Mockery context = new Mockery();
+		final ErasureDecoder decoder = context.mock(ErasureDecoder.class);
+		final FrameWindow window = context.mock(FrameWindow.class);
+		context.checking(new Expectations() {{
+			// First segment
+			one(window).contains(32L);
+			will(returnValue(false));
+			one(window).isTooHigh(32L);
+			will(returnValue(true));
+			// Second segment
+			one(window).contains(0L);
+			will(returnValue(true));
+			one(decoder).decodeFrame(with(any(Frame.class)),
+					with(any(Segment[].class)));
+			will(returnValue(false));
+			// Third segment
+			one(window).contains(0L);
+			will(returnValue(true));
+			one(decoder).decodeFrame(with(any(Frame.class)),
+					with(any(Segment[].class)));
+			will(returnValue(true));
+			// Second call, new window
+			one(window).contains(0L);
+			will(returnValue(false));
+			one(window).isTooHigh(32L);
+			will(returnValue(false));
+		}});
+		IncomingErrorCorrectionLayerImpl err =
+			new IncomingErrorCorrectionLayerImpl(in, decoder, 3, 2);
+		Frame f = new Frame();
+		// The first call discards one segment and decodes two
+		assertTrue(err.readFrame(f, window));
+		// The second call reaches EOF
+		assertFalse(err.readFrame(f, window));
+		// The segment set and discard count should have been freed
+		Map<Long, Segment[]> segmentSets = err.getSegmentSets();
+		assertTrue(segmentSets.isEmpty());
+		Map<Long, Integer> discardCounts = err.getDiscardCounts();
+		assertTrue(discardCounts.isEmpty());
+
+		context.assertIsSatisfied();
+	}
+
+	private static class TestIncomingEncryptionLayer
+	implements IncomingEncryptionLayer {
+
+		private final LinkedList<Long> segmentNumbers;
+		private final int length;
+
+		private TestIncomingEncryptionLayer(LinkedList<Long> segmentNumbers,
+				int length) {
+			this.segmentNumbers = segmentNumbers;
+			this.length = length;
+		}
+
+		public boolean readSegment(Segment s) throws IOException,
+		InvalidDataException {
+			Long segmentNumber = segmentNumbers.poll();
+			if(segmentNumber == null) return false;
+			s.setSegmentNumber(segmentNumber);
+			s.setLength(length);
+			return true;
+		}
+	}
+}