New tests for COSName.writePDF

[Deee92]

Hello!

I tried a few command-line tools on some PDF documents, and found that org.apache.pdfbox.cos.COSName.writePDF(OutputStream) was invoked during the execution.

Here are two tests that verify the invocation of java.io.OutputStream.write(int) within writePDF. The OutputStream object is mocked within the tests.

The following test verifies the parameters with which write should be invoked within writePDF:

@Test
public void testBytesWrittenToOutputStreamForCOSNameType() throws IOException
{
    // Arrange
    COSName cosNameType = COSName.TYPE;
    OutputStream mockOutputStream = Mockito.mock(OutputStream.class);

    // Act
    cosNameType.writePDF(mockOutputStream);

    // Assert
    verify(mockOutputStream, atLeastOnce()).write(47);
    verify(mockOutputStream, atLeastOnce()).write(84);
    verify(mockOutputStream, atLeastOnce()).write(121);
    verify(mockOutputStream, atLeastOnce()).write(112);
    verify(mockOutputStream, atLeastOnce()).write(101);
}

The following test verifies that write should be called exactly five times within writePDF:

@Test
public void testNumberOfBytesWrittenToOutputStreamForCOSNameType() throws IOException
{
    // Arrange
    COSName cosNameType = COSName.TYPE;
    OutputStream mockOutputStream = Mockito.mock(OutputStream.class);

    // Act
    cosNameType.writePDF(mockOutputStream);

    // Assert
    verify(mockOutputStream, times(5)).write(anyInt());
}

What do you think?

Thanks!

[THausherr]

I don't see how this improves test coverage; at most, this shows an interesting example on how to use mockito.

[Deee92]

Hi @THausherr, that's a fair point!
However, the integer parameters (47, 84, 112, 121, 101) with which OutputStream.write(int) is called within COSName.writePDF(OutputStream), as well as the number of times it should be called (5) correspond to actual behavior during execution.
Additionally, I did some mutation analysis, and found that the two tests can kill mutants introduced within writePDF.
These make them potentially useful as regression tests. 🚀

[lehmi]

Your is a valid test, but it won't increase out test coverage as that method in question is covered by other tests already.