'``make_temporary_file`` returns a path to an existing file.'

@given(base_test_cases.map(make_test_case), binary(average_size=20))
def test_make_temporary_file_with_content(self, test, content):

    temp_file = test.make_temporary_file(content)
    self.addCleanup(temp_file.remove)
    self.assertThat(temp_file, file_contents(Equals(content)))
