def _generate_summary(self):
    """Generates a validation summary string"""
    failures = self.failures
    summary = """
Test: `{}` ({} of {} passed)
=============================================================================
The following files are in error:\n
""".format(self.name, self.n_passed, self.len)

    if len(failures) == 0:
        failures = ['None\n']
    for f in failures:
        summary += f

    summary += """
-----------------------------------------------------------------------------
"""
    return summary