How to test Hadoop Mappers with and without MRUnit

TestWithMRUnit.java

    @Test
    public void shouldMapDocument() throws IOException, InterruptedException {
        new MapDriver(new DocumentMapper())
            .withInput(createDocumentForTest())
            .withOutput(expected0)
            .withOutput(expected1)
            .runTest();
    }

TestWithoutMRUnit.java

    @Test
    public void shouldMapDocument() throws IOException, InterruptedException {
        final List<Symbol> mapOutput = new ArrayList<Symbol>(); // this is a closure
        
        Document input = createDocumentForTest();

        DocumentMapperTest.Context context = new Context(
                new Configuration(),
                new TaskAttemptID(),
                null, // <- oh, nulls. holy boilerplate!
                null,
                null,
                null,
                null
        ) {
            public void write(Text key, Symbol symbol) // look! I'm a wannabe-javascript function.
            {
                mapOutput .add(symbol); // <- here we use this closure
            }
        };

        DocumentMapperTest mapper = new DocumentMapperTest();

        mapper.map(new Text("Q123"), input, context);

        assertEquals(2, mapOutput .size());
        assertEquals(expected0, mapOutput.get(0));
        assertEquals(expected1, mapOutput.get(1));
    }