Merge pull request numpy#19525 from BvB93/optional

 TST: Test that `numpy.typing` can be imported in the absence of typing-extensions

Author: seberg

numpy/tests/test_reloading.py

@@ -57,5 +57,8 @@ def test_full_reimport():
         with warns(UserWarning):
             import numpy as np
         """)
-    p = subprocess.run([sys.executable, '-c', code])
-
+    p = subprocess.run([sys.executable, '-c', code], capture_output=True)
+    if p.returncode:
+        raise AssertionError(
+            f"Non-zero return code: {p.returncode!r}\n\n{p.stderr.decode()}"
+        )

numpy/typing/tests/test_typing_extensions.py

@@ -0,0 +1,35 @@
+"""Tests for the optional typing-extensions dependency."""
+
+import sys
+import textwrap
+import subprocess
+
+CODE = textwrap.dedent(r"""
+    import sys
+    import importlib
+
+    assert "typing_extensions" not in sys.modules
+    assert "numpy.typing" not in sys.modules
+
+    # Importing `typing_extensions` will now raise an `ImportError`
+    sys.modules["typing_extensions"] = None
+    assert importlib.import_module("numpy.typing")
+""")
+
+
+def test_no_typing_extensions() -> None:
+    """Import `numpy.typing` in the absence of typing-extensions.
+
+    Notes
+    -----
+    Ideally, we'd just run the normal typing tests in an environment where
+    typing-extensions is not installed, but unfortunatelly this is currently
+    impossible as it is an indirect hard dependency of pytest.
+
+    """
+    p = subprocess.run([sys.executable, '-c', CODE], capture_output=True)
+    if p.returncode:
+        raise AssertionError(
+            f"Non-zero return code: {p.returncode!r}\n\n{p.stderr.decode()}"
+        )
+