text: Title: assert_match does not fail assertion
  Body: **Describe the bug**
  
  `snapshot.assert_match(ANY)` always passed
  
  **To Reproduce**
  Steps to reproduce the behavior:
  1. Replace with `snapshot.assert_match(None)`
  https://github.com/tophat/syrupy/blob/a5c46b15942e4d75c9470b24f3e2bfc9fa661087/tests/test_snapshots.py#L14
  2. Run command `inv test`
  3. See that test does not fail
  
  **Expected behavior**
  
  Should fail with the same error as `assert None == snapshot`
  