run_tests: move CQ test skips here

Our recipes have been disabling a bunch of tests.  To increase
visibility, and to make it easier to test changes, move that
logic to this script.

Change-Id: I3894f047715177c0f1d27a2fe4c3490972dab204
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/462881
Tested-by: Mike Frysinger <vapier@google.com>
Reviewed-by: Gavin Mak <gavinmak@google.com>

run_tests

@@ -15,9 +15,11 @@
 
 """Wrapper to run linters and pytest with the right settings."""
 
+import functools
 import os
 import subprocess
 import sys
+from typing import List
 
 import pytest
 
@@ -25,6 +27,33 @@ import pytest
 ROOT_DIR = os.path.dirname(os.path.realpath(__file__))
 
 
+@functools.lru_cache()
+def is_ci() -> bool:
+    """Whether we're running in our CI system."""
+    return os.getenv("LUCI_CQ") == "yes"
+
+
+def run_pytest(argv: List[str]) -> int:
+    """Returns the exit code from pytest."""
+    if is_ci():
+        # TODO(b/266734831): Find out why smoke tests fail.
+        # TODO(b/266734831): Find out why each superproject test takes 8m+.
+        tests_to_skip = (
+            "test_smoke_repo",
+            "test_smoke_git",
+            "test_superproject_get_superproject_invalid_branch",
+            "test_superproject_get_superproject_invalid_url",
+        )
+
+        print("WARNING: Skipping tests:", tests_to_skip)
+        argv = [
+            "-k",
+            " and ".join(f"not {x}" for x in tests_to_skip),
+        ] + argv
+
+    return pytest.main(argv)
+
+
 def run_black():
     """Returns the exit code from black."""
     # Black by default only matches .py files.  We have to list standalone
@@ -58,7 +87,7 @@ def run_isort():
 def main(argv):
     """The main entry."""
     checks = (
-        lambda: pytest.main(argv),
+        functools.partial(run_pytest, argv),
         run_black,
         run_flake8,
         run_isort,