Unit tests for OutgoingEncryptionLayer.

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

@@ -1,6 +1,9 @@
 package net.sf.briar.transport;
 
+import static javax.crypto.Cipher.ENCRYPT_MODE;
+import static net.sf.briar.api.transport.TransportConstants.AAD_LENGTH;
 import static net.sf.briar.api.transport.TransportConstants.HEADER_LENGTH;
+import static net.sf.briar.api.transport.TransportConstants.IV_LENGTH;
 import static net.sf.briar.api.transport.TransportConstants.MAC_LENGTH;
 import static net.sf.briar.api.transport.TransportConstants.TAG_LENGTH;
 
@@ -11,6 +14,7 @@ import javax.crypto.Cipher;
 import net.sf.briar.BriarTestCase;
 import net.sf.briar.api.crypto.AuthenticatedCipher;
 import net.sf.briar.api.crypto.CryptoComponent;
+import net.sf.briar.api.crypto.ErasableKey;
 import net.sf.briar.crypto.CryptoModule;
 
 import org.junit.Test;
@@ -20,8 +24,6 @@ import com.google.inject.Injector;
 
 public class OutgoingEncryptionLayerTest extends BriarTestCase {
 
-	// FIXME: Write more tests
-
 	private final CryptoComponent crypto;
 	private final Cipher tagCipher;
 	private final AuthenticatedCipher frameCipher;
@@ -34,12 +36,70 @@ public class OutgoingEncryptionLayerTest extends BriarTestCase {
 		frameCipher = crypto.getFrameCipher();
 	}
 
+	@Test
+	public void testEncryption() throws Exception {
+		int frameLength = 1024, payloadLength = 123;
+		byte[] tag = new byte[TAG_LENGTH];
+		byte[] iv = new byte[IV_LENGTH], aad = new byte[AAD_LENGTH];
+		byte[] plaintext = new byte[frameLength - MAC_LENGTH];
+		byte[] ciphertext = new byte[frameLength];
+		ErasableKey tagKey = crypto.generateTestKey();
+		ErasableKey frameKey = crypto.generateTestKey();
+		// Calculate the expected tag
+		TagEncoder.encodeTag(tag, tagCipher, tagKey);
+		// Calculate the expected ciphertext
+		FrameEncoder.encodeIv(iv, 0);
+		FrameEncoder.encodeAad(aad, 0, plaintext.length);
+		frameCipher.init(ENCRYPT_MODE, frameKey, iv, aad);
+		FrameEncoder.encodeHeader(plaintext, false, payloadLength);
+		frameCipher.doFinal(plaintext, 0, plaintext.length, ciphertext, 0);
+		// Check that the actual tag and ciphertext match what's expected
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		OutgoingEncryptionLayer o = new OutgoingEncryptionLayer(out, 10 * 1024,
+				tagCipher, frameCipher, tagKey, frameKey, frameLength);
+		o.writeFrame(new byte[frameLength - MAC_LENGTH], payloadLength, false);
+		byte[] actual = out.toByteArray();
+		assertEquals(TAG_LENGTH + frameLength, actual.length);
+		for(int i = 0; i < TAG_LENGTH; i++) {
+			assertEquals(tag[i], actual[i]);
+		}
+		for(int i = 0; i < frameLength; i++) {
+			assertEquals("" + i, ciphertext[i], actual[TAG_LENGTH + i]);
+		}
+	}
+
+	@Test
+	public void testInitiatorClosesConnectionWithoutWriting() throws Exception {
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		// Initiator's constructor
+		OutgoingEncryptionLayer o = new OutgoingEncryptionLayer(out, 10 * 1024,
+				tagCipher, frameCipher, crypto.generateTestKey(),
+				crypto.generateTestKey(), 1024);
+		// Write an empty final frame without having written any other frames
+		o.writeFrame(new byte[1024], 0, true);
+		// Nothing should be written to the output stream
+		assertEquals(0, out.size());
+	}
+
+	@Test
+	public void testResponderClosesConnectionWithoutWriting() throws Exception {
+		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		// Responder's constructor
+		OutgoingEncryptionLayer o = new OutgoingEncryptionLayer(out, 10 * 1024,
+				frameCipher, crypto.generateTestKey(), 1024);
+		// Write an empty final frame without having written any other frames
+		o.writeFrame(new byte[1024], 0, true);
+		// An empty final frame should be written to the output stream
+		assertEquals(HEADER_LENGTH + MAC_LENGTH, out.size());
+	}
+
 	@Test
 	public void testRemainingCapacityWithTag() throws Exception {
 		int frameLength = 1024;
 		int maxPayloadLength = frameLength - HEADER_LENGTH - MAC_LENGTH;
 		long capacity = 10 * frameLength;
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		// Initiator's constructor
 		OutgoingEncryptionLayer o = new OutgoingEncryptionLayer(out, capacity,
 				tagCipher, frameCipher, crypto.generateTestKey(),
 				crypto.generateTestKey(), frameLength);
@@ -48,9 +108,9 @@ public class OutgoingEncryptionLayerTest extends BriarTestCase {
 		assertEquals(10 * maxPayloadLength - TAG_LENGTH,
 				o.getRemainingCapacity());
 		// Write nine frames, each containing a partial payload
-		for(int i = 9; i > 0; i--) {
+		for(int i = 0; i < 9; i++) {
 			o.writeFrame(frame, 123, false);
-			assertEquals(i * maxPayloadLength - TAG_LENGTH,
+			assertEquals((9 - i) * maxPayloadLength - TAG_LENGTH,
 					o.getRemainingCapacity());
 		}
 		// Write the final frame, which will not be padded
@@ -66,15 +126,16 @@ public class OutgoingEncryptionLayerTest extends BriarTestCase {
 		int maxPayloadLength = frameLength - HEADER_LENGTH - MAC_LENGTH;
 		long capacity = 10 * frameLength;
 		ByteArrayOutputStream out = new ByteArrayOutputStream();
+		// Responder's constructor
 		OutgoingEncryptionLayer o = new OutgoingEncryptionLayer(out, capacity,
 				frameCipher, crypto.generateTestKey(), frameLength);
 		// There should be space for ten full frames
 		assertEquals(10 * maxPayloadLength, o.getRemainingCapacity());
 		// Write nine frames, each containing a partial payload
 		byte[] frame = new byte[frameLength];
-		for(int i = 9; i > 0; i--) {
+		for(int i = 0; i < 9; i++) {
 			o.writeFrame(frame, 123, false);
-			assertEquals(i * maxPayloadLength, o.getRemainingCapacity());
+			assertEquals((9 - i) * maxPayloadLength, o.getRemainingCapacity());
 		}
 		// Write the final frame, which will not be padded
 		o.writeFrame(frame, 123, true);