Fix fork-skip guards for local test runs (#524 rebased, ssh:// origin form folded in) (#563)

* Fix fork-skip guards for local test runs

The fork skip read GITHUB_REPOSITORY with an upstream fallback, so local runs on a fork always ran the upstream-only guards. Share one helper that checks the origin remote when the variable is unset. Fixes #496.

* test: accept the ssh:// origin form in the upstream-checkout helper

An upstream clone whose origin is ssh://git@github.com/MadsLorentzen/ai-job-search(.git)
must keep running the placeholder guards; the helper only knew the https and
scp-style forms. Folded in at maintainer rebase per the #524 review.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

---------

Co-authored-by: Omarinho12345 <omarottelli720@gmail.com>
Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

tests/test_upstream_checkout.py

@@ -0,0 +1,105 @@
+"""Unit tests for the shared fork-detection helper (issue #496).
+
+The placeholder guards must skip on personalized forks even in a local run
+where GITHUB_REPOSITORY is unset. All branches are exercised with the env
+and subprocess.run patched, so no git remote or CI variable is needed.
+"""
+import os
+import subprocess
+import unittest
+from unittest import mock
+
+try:
+    from tests import _upstream
+    from tests._upstream import is_upstream_checkout
+except ImportError:  # `python -m unittest discover -s tests` imports test modules top-level
+    import _upstream
+    from _upstream import is_upstream_checkout
+
+UPSTREAM = "MadsLorentzen/ai-job-search"
+
+
+def _no_github_env(testcase):
+    """Clear GITHUB_REPOSITORY so the origin-remote branch is exercised."""
+    patcher = mock.patch.dict(os.environ)
+    env = patcher.start()
+    testcase.addCleanup(patcher.stop)
+    env.pop("GITHUB_REPOSITORY", None)
+    return env
+
+
+def _completed(stdout="", returncode=0):
+    return subprocess.CompletedProcess(
+        args=["git", "remote", "get-url", "origin"],
+        returncode=returncode,
+        stdout=stdout,
+    )
+
+
+class UpstreamCheckoutTests(unittest.TestCase):
+    def test_env_says_upstream(self):
+        with mock.patch.dict(os.environ, {"GITHUB_REPOSITORY": UPSTREAM}):
+            with mock.patch.object(_upstream.subprocess, "run") as run:
+                self.assertTrue(is_upstream_checkout())
+                run.assert_not_called()
+
+    def test_env_says_fork(self):
+        with mock.patch.dict(os.environ, {"GITHUB_REPOSITORY": "someone-else/ai-job-search"}):
+            with mock.patch.object(_upstream.subprocess, "run") as run:
+                self.assertFalse(is_upstream_checkout())
+                run.assert_not_called()
+
+    def test_no_env_and_origin_is_fork(self):
+        _no_github_env(self)
+        with mock.patch.object(
+            _upstream.subprocess, "run", return_value=_completed("git@github.com:someone-else/ai-job-search.git\n")
+        ):
+            self.assertFalse(is_upstream_checkout())
+
+    def test_no_env_and_git_is_unavailable(self):
+        _no_github_env(self)
+        with mock.patch.object(
+            _upstream.subprocess, "run", side_effect=OSError("no git on PATH")
+        ):
+            self.assertTrue(is_upstream_checkout())
+
+    def test_no_env_and_git_times_out(self):
+        _no_github_env(self)
+        with mock.patch.object(
+            _upstream.subprocess,
+            "run",
+            side_effect=subprocess.TimeoutExpired(cmd="git", timeout=10),
+        ):
+            self.assertTrue(is_upstream_checkout())
+
+    def test_no_env_and_git_exits_nonzero(self):
+        _no_github_env(self)
+        with mock.patch.object(
+            _upstream.subprocess, "run", return_value=_completed("", returncode=128)
+        ):
+            self.assertTrue(is_upstream_checkout())
+
+    def test_origin_url_forms(self):
+        cases = [
+            ("https://github.com/MadsLorentzen/ai-job-search", True),
+            ("https://github.com/MadsLorentzen/ai-job-search.git", True),
+            ("git@github.com:MadsLorentzen/ai-job-search", True),
+            ("git@github.com:MadsLorentzen/ai-job-search.git", True),
+            ("ssh://git@github.com/MadsLorentzen/ai-job-search.git", True),
+            ("ssh://git@github.com/MadsLorentzen/ai-job-search", True),
+            ("ssh://git@github.com/someone-else/ai-job-search.git", False),
+            ("https://github.com/someone-else/ai-job-search.git", False),
+            ("git@github.com:someone-else/ai-job-search", False),
+            ("https://gitlab.com/MadsLorentzen/ai-job-search.git", False),
+        ]
+        for url, expected in cases:
+            with self.subTest(url=url):
+                _no_github_env(self)
+                with mock.patch.object(
+                    _upstream.subprocess, "run", return_value=_completed(url + "\n")
+                ):
+                    self.assertEqual(is_upstream_checkout(), expected)
+
+
+if __name__ == "__main__":
+    unittest.main()