Restoring tests

src/test/java/com/github/davidcarboni/restolino/json/SerialiserTest.java

@@ -1,7 +1,6 @@
 package com.github.davidcarboni.restolino.json;
 
 import org.junit.Test;
-import org.junit.function.ThrowingRunnable;
 
 import java.io.IOException;
 import java.nio.file.Files;
@@ -13,7 +12,7 @@
 import java.util.concurrent.atomic.AtomicLong;
 
 import static org.junit.Assert.assertNotEquals;
-import static org.junit.Assert.assertThrows;
+import static org.junit.Assert.assertNull;
 
 /**
  * Tests for {@link Serialiser}.
@@ -72,7 +71,7 @@ public Exception call() throws Exception {
         // Then
         // All tasks should complete without exceptions
         for (Future<Exception> task : tasks) {
-            assertThrows(NullPointerException.class, (ThrowingRunnable) task.get());
+            assertNull(task.get());
         }
         // Sometimes another thread will have serialised before deserialisation:
         assertNotEquals(same.get(), different.get());