diff --git a/bramble-core/src/test/java/org/briarproject/bramble/connection/ConnectionChooserImplTest.java b/bramble-core/src/test/java/org/briarproject/bramble/connection/ConnectionChooserImplTest.java
new file mode 100644
index 000000000..82ddc02ab
--- /dev/null
+++ b/bramble-core/src/test/java/org/briarproject/bramble/connection/ConnectionChooserImplTest.java
@@ -0,0 +1,80 @@
+package org.briarproject.bramble.connection;
+
+import org.briarproject.bramble.api.contact.ContactId;
+import org.briarproject.bramble.api.plugin.TransportId;
+import org.briarproject.bramble.api.sync.Priority;
+import org.briarproject.bramble.test.BrambleMockTestCase;
+import org.jmock.Expectations;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.briarproject.bramble.api.sync.SyncConstants.PRIORITY_NONCE_BYTES;
+import static org.briarproject.bramble.test.TestUtils.getContactId;
+import static org.briarproject.bramble.test.TestUtils.getRandomBytes;
+import static org.briarproject.bramble.test.TestUtils.getTransportId;
+import static org.briarproject.bramble.util.StringUtils.fromHexString;
+
+public class ConnectionChooserImplTest extends BrambleMockTestCase {
+
+	private final InterruptibleConnection conn1 =
+			context.mock(InterruptibleConnection.class, "conn1");
+	private final InterruptibleConnection conn2 =
+			context.mock(InterruptibleConnection.class, "conn2");
+
+	private final ContactId contactId = getContactId();
+	private final TransportId transportId = getTransportId();
+
+	private final Priority low =
+			new Priority(fromHexString("00000000000000000000000000000000"));
+	private final Priority high =
+			new Priority(fromHexString("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"));
+
+	private ConnectionChooserImpl chooser;
+
+	@Before
+	public void setUp() {
+		chooser = new ConnectionChooserImpl();
+	}
+
+	@Test
+	public void testOldConnectionIsInterruptedIfNewHasHigherPriority() {
+		chooser.addConnection(contactId, transportId, conn1, low);
+
+		context.checking(new Expectations() {{
+			oneOf(conn1).interruptOutgoingSession();
+		}});
+
+		chooser.addConnection(contactId, transportId, conn2, high);
+	}
+
+	@Test
+	public void testNewConnectionIsInterruptedIfOldHasHigherPriority() {
+		chooser.addConnection(contactId, transportId, conn1, high);
+
+		context.checking(new Expectations() {{
+			oneOf(conn2).interruptOutgoingSession();
+		}});
+
+		chooser.addConnection(contactId, transportId, conn2, low);
+	}
+
+	@Test
+	public void testConnectionIsNotInterruptedAfterBeingRemoved() {
+		chooser.addConnection(contactId, transportId, conn1, low);
+		chooser.removeConnection(contactId, transportId, conn1);
+		chooser.addConnection(contactId, transportId, conn2, high);
+	}
+
+	@Test
+	public void testConnectionIsInterruptedIfAddedTwice() {
+		chooser.addConnection(contactId, transportId, conn1,
+				new Priority(getRandomBytes(PRIORITY_NONCE_BYTES)));
+
+		context.checking(new Expectations() {{
+			oneOf(conn1).interruptOutgoingSession();
+		}});
+
+		chooser.addConnection(contactId, transportId, conn1,
+				new Priority(getRandomBytes(PRIORITY_NONCE_BYTES)));
+	}
+}