Add mypy type checking

.pre-commit-config.yaml

@@ -37,5 +37,11 @@ repos:
     rev: v2.2.4
     hooks:
       - id: codespell
+
+  - repo: https://github.com/pre-commit/mirrors-mypy
+    rev: 'v1.1.1'  # Use the sha / tag you want to point at
+    hooks:
+      - id: mypy
+        additional_dependencies: ['types-setuptools']
 ci:
   autofix_prs: false

changelog/133.feature.rst

@@ -0,0 +1,2 @@
+``mypy`` type checking has been enabled on the repository.
+Types have not yet been extensively added, but running ``mypy`` does not raise any errors.

docs/conf.py

@@ -21,7 +21,7 @@
     try:
         get_distribution(requirement)
     except Exception as e:
-        missing_requirements.append(requirement.name)
+        missing_requirements.append(requirement.project_name)
 if missing_requirements:
     print(
         f"The {' '.join(missing_requirements)} package(s) could not be found and "

sunkit_image/__init__.py

@@ -8,6 +8,7 @@
 * Documentation: https://sunkit-image.readthedocs.io/en/latest/
 """
 import sys
+from typing import List
 
 from .version import version as __version__
 
@@ -25,4 +26,4 @@ class UnsupportedPythonError(Exception):
     # This has to be .format to keep backwards compatibly.
     raise UnsupportedPythonError("sunkit_image does not support Python < {}".format(__minimum_python_version__))
 
-__all__ = []
+__all__: List[str] = []

sunkit_image/tests/conftest.py

@@ -1,6 +1,6 @@
 import os
 import tempfile
-import importlib
+import importlib.util
 
 import numpy as np
 import pytest

sunkit_image/tests/test_trace.py

@@ -236,16 +236,6 @@ def test_erase_loop_in_image(image, test_map):
     assert np.allclose(expect, result)
 
 
-@pytest.fixture
-def test_image():
-    # An image containing a loop in a straight line
-    ima = np.zeros((3, 3), dtype=np.float32)
-    ima[0, 1] = 5
-    ima[1, 1] = 3
-    ima[2, 1] = 0
-    return ima
-
-
 def test_initial_direction_finding(test_image):
     # The starting point of the loop i.e. the maximumflux position
     xstart = 0

sunkit_image/time_lag.py

@@ -4,6 +4,8 @@
 
 Useful for understanding time variability in EUV light curves.
 """
+from typing import Optional
+
 import numpy as np
 
 import astropy.units as u
@@ -162,7 +164,7 @@ def _dask_check(lags, indices):
 
 
 @u.quantity_input
-def time_lag(signal_a, signal_b, time: u.s, lag_bounds: (u.s, None) = None, **kwargs):
+def time_lag(signal_a, signal_b, time: u.s, lag_bounds: Optional[u.Quantity[u.s]] = None, **kwargs):
     r"""
     Compute the time lag that maximizes the cross-correlation between
     ``signal_a`` and ``signal_b``.
@@ -236,7 +238,7 @@ def time_lag(signal_a, signal_b, time: u.s, lag_bounds: (u.s, None) = None, **kw
 
 
 @u.quantity_input
-def max_cross_correlation(signal_a, signal_b, time: u.s, lag_bounds: (u.s, None) = None):
+def max_cross_correlation(signal_a, signal_b, time: u.s, lag_bounds: Optional[u.Quantity[u.s]] = None):
     """
     Compute the maximum value of the cross-correlation between ``signal_a`` and
     ``signal_b``.

sunkit_image/version.py

@@ -1,3 +1,5 @@
+# mypy: disable-error-code="no-redef"
+
 # NOTE: First try _dev.scm_version if it exists and setuptools_scm is installed
 # This file is not included in sunkit-image wheels/tarballs, so otherwise it will
 # fall back on the generated _version module.