Skip mypy install for pypy and mypy tests if it's not installed (#2905)

Author: cdce8p

requirements_minimal.txt

@@ -6,4 +6,4 @@ tbump~=6.11
 coverage~=7.12
 pytest
 pytest-cov~=7.0
-mypy
+mypy; platform_python_implementation!="PyPy"

tests/test_raw_building.py

@@ -19,7 +19,6 @@
 from typing import Any
 from unittest import mock
 
-import mypy.build
 import pytest
 
 import tests.testdata.python3.data.fake_module_with_broken_getattr as fm_getattr
@@ -37,6 +36,13 @@
     object_build_class,
 )
 
+try:
+    import mypy.build
+
+    HAS_MYPY = True
+except ImportError:
+    HAS_MYPY = False
+
 DUMMY_MOD = build_module("DUMMY")
 
 
@@ -173,6 +179,7 @@ def mocked_sys_modules_getitem(name: str) -> types.ModuleType | CustomGetattr:
     assert not err
 
 
+@pytest.mark.skipif(not HAS_MYPY, reason="This test requires mypy")
 def test_missing__dict__():
     # This shouldn't raise an exception.
     object_build_class(DUMMY_MOD, mypy.build.ModuleNotFound)