when does CSVWriter throws exception when csvWriter.close()?

Question

I am trying to cover a Unit test case for an Exception. my code looks like this

if (null != csvWriter) {
        try {
          csvWriter.close();
        } catch (Exception ee) {
          log.error("Error in closing csvWriter. You may loose content.");
        }
      }

I want to cover the exception in Mockito unit case. Is there a way?

Mockito is a mocking-framework. Do you mean to cover the possible exception throw in a JUnit Test case? — Valerij Dobler, Jan 17 '22 at 14:22
You could try to close the writer more than once, that should throw. — Valerij Dobler, Mar 17 '22 at 17:24

score 0 · Answer 1 · answered Mar 17 '22 at 17:24

Suppose your CSVWriter is a fake. Then you could make it throw an exception on calling the close method.

@Test
void csvWriterThrows() throws IOException
{
    final CSVWriter csvWriter = Mockito.mock(CSVWriter.class);
    Mockito.doThrow(IOException.class).when(csvWriter).close();

    final IOException ioException = Assertions.assertThrows(IOException.class, csvWriter::close);

    Assertions.assertEquals(IOException.class, ioException.getClass());
    # more assertions...
}

when does CSVWriter throws exception when csvWriter.close()?

1 Answers1