Run mypy in pre-commit

Author: michaelosthege

.pre-commit-config.yaml

@@ -31,3 +31,7 @@ repos:
       args: [--rcfile=.pylintrc]
       exclude: (test_*|mcbackend/meta.py|mcbackend/npproto/)
       files: ^mcbackend/
+-   repo: https://github.com/pre-commit/mirrors-mypy
+    rev: v0.991
+    hooks:
+    -   id: mypy

mcbackend/test_core.py

@@ -72,10 +72,10 @@ def test_chain_properties(self):
 
     def test_chain_length(self):
         class _TestChain(core.Chain):
-            def get_draws(self, var_name: str):
+            def get_draws(self, var_name: str, slc: slice = slice(None)):
                 return numpy.arange(12)
 
-            def get_stats(self, stat_name: str):
+            def get_stats(self, stat_name: str, slc: slice = slice(None)):
                 return numpy.arange(42)
 
         rmeta = RunMeta("test", variables=[Variable("v1")])

mcbackend/test_utils.py

@@ -1,7 +1,7 @@
 import random
 import time
 from dataclasses import dataclass
-from typing import Sequence
+from typing import Optional, Sequence
 
 import arviz
 import hagelkorn
@@ -78,9 +78,9 @@ def make_draw(variables: Sequence[Variable]):
 class BaseBackendTest:
     """Can be used to test different backends in the same way."""
 
-    cls_backend = None
-    cls_run = None
-    cls_chain = None
+    cls_backend: Optional[type] = None
+    cls_run: Optional[type] = None
+    cls_chain: Optional[type] = None
 
     def setup_method(self, method):
         """Override this when the backend has no parameterless constructor."""
@@ -373,10 +373,8 @@ def run_all_benchmarks(self) -> pandas.DataFrame:
         for attr in dir(BackendBenchmark):
             meth = getattr(self, attr, None)
             if callable(meth) and meth.__name__.startswith("measure_"):
-                try:
+                if hasattr(self, "setup_method"):
                     self.setup_method(meth)
-                except TypeError:
-                    pass
                 print(f"Running {meth.__name__}")
                 speed = meth()
                 df.loc[meth.__name__[8:], ["bytes_per_draw", "append_speed", "description"]] = (