added cov to readme

README.md

@@ -1,5 +1,7 @@
 # Pre-commit hooks
 
+[![codecov](https://codecov.io/gh/atlas-bi/pre-commit-hooks/branch/master/graph/badge.svg?token=ZPTK2KIAfN)](https://codecov.io/gh/atlas-bi/pre-commit-hooks)
+
 ## Clean Model Context
 
 This pre-commit hook is used to remove connection strings from a dotnet model context from the auto generated (scaffold) model context. Dotnet inserts the connection string that was used to generate the model, and adds a note that it should be removed :) Thank Dotnet for adding an extra step for developers to loose sleep over 😢

tests/conftest.py

@@ -1,5 +1,5 @@
 import subprocess
-from typing import Any, List, Optional, Set
+from typing import Any, Optional
 
 import pytest
 

tests/test_clean_model_context.py

@@ -4,7 +4,7 @@
 from testing.util import get_resource_path
 
 
-def test_failing_file(tmpdir):
+def test_failing_file(tmpdir) -> None:
     f = tmpdir.join("Atlas_WebContext.cs")
     f.write_text(
         Path(get_resource_path("Atlas_WebContext.cs")).read_text("utf8"),
@@ -20,7 +20,7 @@ def test_no_file():
     assert main([]) == 0
 
 
-def test_other_file(tmpdir):
+def test_other_file(tmpdir) -> None:
     f = tmpdir.join("other.cs")
     f.write_text(
         Path(get_resource_path("Atlas_WebContext.cs")).read_text("utf8"),