Add interop tests for pkg_resources and zope-interface

setuptools/tests/integration/test_zope_interface.py

@@ -0,0 +1,61 @@
+import platform
+import subprocess
+import sys
+from inspect import cleandoc
+
+import jaraco.path
+import pytest
+
+pytestmark = pytest.mark.integration
+
+VIRTUALENV = (sys.executable, "-m", "virtualenv")
+
+
+def run(cmd, **kwargs):
+    proc = subprocess.run(cmd, encoding="utf-8", capture_output=True, **kwargs)
+    if proc.returncode != 0:
+        pytest.fail(f"Command {cmd} failed with:\n{proc.stdout=!s}\n{proc.stderr=!s}")
+    return proc.stdout
+
+
+@pytest.mark.skipif(
+    platform.system() != "Linux",
+    reason="only demonstrated to fail on Linux in #4399",
+)
+def test_interop_pkg_resources_iter_entry_points(tmp_path, venv):
+    """
+    Importing pkg_resources.iter_entry_points on console_scripts
+    seems to cause trouble with zope-interface, when deprecates installation method
+    is used. See #4399.
+    """
+    project = {
+        "pkg": {
+            "foo.py": cleandoc(
+                """
+                from pkg_resources import iter_entry_points
+
+                def bar():
+                    print("Print me if you can")
+                """
+            ),
+            "setup.py": cleandoc(
+                """
+                from setuptools import setup, find_packages
+
+                setup(
+                    install_requires=["zope-interface==6.4.post2"],
+                    entry_points={
+                        "console_scripts": [
+                            "foo=foo:bar",
+                        ],
+                    },
+                )
+                """
+            ),
+        }
+    }
+    jaraco.path.build(project, prefix=tmp_path)
+    cmd = [venv.exe("pip"), "install", "-e", ".", "--no-use-pep517"]
+    run(cmd, cwd=tmp_path / "pkg")
+    out = run([venv.exe("foo")])
+    assert "Print me if you can" in out