diff --git a/bramble-core/src/test/java/org/briarproject/bramble/test/DbExpectations.java b/bramble-core/src/test/java/org/briarproject/bramble/test/DbExpectations.java
index 17682e78d..6f2a0c104 100644
--- a/bramble-core/src/test/java/org/briarproject/bramble/test/DbExpectations.java
+++ b/bramble-core/src/test/java/org/briarproject/bramble/test/DbExpectations.java
@@ -25,7 +25,8 @@ public class DbExpectations extends Expectations {
 	protected <R, E extends Exception> NullableDbCallable<R, E> withNullableDbCallable(
 			Transaction txn) {
 		addParameterMatcher(any(NullableDbCallable.class));
-		currentBuilder().setAction(new RunTransactionWithResultAction(txn));
+		currentBuilder().setAction(
+				new RunTransactionWithNullableResultAction(txn));
 		return null;
 	}
 
diff --git a/bramble-core/src/test/java/org/briarproject/bramble/test/RunTransactionWithNullableResultAction.java b/bramble-core/src/test/java/org/briarproject/bramble/test/RunTransactionWithNullableResultAction.java
new file mode 100644
index 000000000..9ed991c92
--- /dev/null
+++ b/bramble-core/src/test/java/org/briarproject/bramble/test/RunTransactionWithNullableResultAction.java
@@ -0,0 +1,28 @@
+package org.briarproject.bramble.test;
+
+import org.briarproject.bramble.api.db.NullableDbCallable;
+import org.briarproject.bramble.api.db.Transaction;
+import org.hamcrest.Description;
+import org.jmock.api.Action;
+import org.jmock.api.Invocation;
+
+public class RunTransactionWithNullableResultAction implements Action {
+
+	private final Transaction txn;
+
+	public RunTransactionWithNullableResultAction(Transaction txn) {
+		this.txn = txn;
+	}
+
+	@Override
+	public Object invoke(Invocation invocation) throws Throwable {
+		NullableDbCallable task =
+				(NullableDbCallable) invocation.getParameter(1);
+		return task.call(txn);
+	}
+
+	@Override
+	public void describeTo(Description description) {
+		description.appendText("runs a task inside a database transaction");
+	}
+}