def test_is_file_structure_valid_returns_true_on_three_headers(self):
fv = FileValidator()
result = fv.is_file_structure_valid(['a', 'b', 'c'])
self.assertTrue(result)
def test_is_file_structure_valid_returns_false_on_empty_headers(self):
fv = FileValidator()
result = fv.is_file_structure_valid([])
self.assertFalse(result)
def test_is_file_structure_valid_returns_false_on_missing_headers(self):
fv = FileValidator()
result = fv.is_file_structure_valid(None)
self.assertFalse(result)
def test_is_file_structure_valid_returns_false_on_too_many_headers(self):
fv = FileValidator()
result = fv.is_file_structure_valid(['a', 'b', 'c', 'd'])
self.assertFalse(result)