test: update vcs tests to take git 'init.defaultBranch' config into account

I recently updated my local `init.defaultBranch` setting in git from
`master` -> `main`, and this broke a bunch of Taskgraph tests. Let's make
them a bit smarter.

Author: ahal

test/fixtures/vcs.py

@@ -57,6 +57,17 @@ def git_repo(tmpdir_factory):
     yield repo_dir
 
 
+@pytest.fixture(scope="package")
+def default_git_branch():
+    proc = subprocess.run(
+        ["git", "config", "init.defaultBranch"],
+        capture_output=True,
+        check=False,
+        text=True,
+    )
+    return proc.stdout.strip() or "master"
+
+
 def _build_env_with_git_date_env_vars(date_time_string):
     env = os.environ.copy()
     env.update({env_var: date_time_string for env_var in _GIT_DATE_ENV_VARS})
@@ -90,30 +101,37 @@ def repo(request, hg_repo, git_repo, monkeypatch, tmpdir):
     return get_repository(repodir)
 
 
-def create_remote_repo(tmpdir, repo, remote_name, remote_path):
-    if repo.tool == "hg":
-        repo.run("phase", "--public", ".")
+@pytest.fixture
+def create_remote_repo(default_git_branch):
 
-    shutil.copytree(repo.path, str(tmpdir / remote_path))
+    def inner(tmpdir, repo, remote_name, remote_path):
+        if repo.tool == "hg":
+            repo.run("phase", "--public", ".")
 
-    if repo.tool == "git":
-        repo.run("remote", "add", remote_name, f"{tmpdir}/{remote_path}")
-        repo.run("fetch", remote_name)
-        repo.run("branch", "--set-upstream-to", f"{remote_name}/master")
-    if repo.tool == "hg":
-        with open(os.path.join(repo.path, ".hg/hgrc"), "a") as f:
-            f.write(f"[paths]\n{remote_name} = {tmpdir}/{remote_path}\n")
+        shutil.copytree(repo.path, str(tmpdir / remote_path))
+
+        if repo.tool == "git":
+            repo.run("remote", "add", remote_name, f"{tmpdir}/{remote_path}")
+            repo.run("fetch", remote_name)
+            repo.run(
+                "branch", "--set-upstream-to", f"{remote_name}/{default_git_branch}"
+            )
+        if repo.tool == "hg":
+            with open(os.path.join(repo.path, ".hg/hgrc"), "a") as f:
+                f.write(f"[paths]\n{remote_name} = {tmpdir}/{remote_path}\n")
+
+    return inner
 
 
 @pytest.fixture
-def repo_with_remote(tmpdir, repo):
+def repo_with_remote(tmpdir, create_remote_repo, repo):
     remote_name = "upstream"
     create_remote_repo(tmpdir, repo, remote_name, "remote_repo")
     return repo, remote_name
 
 
 @pytest.fixture
-def repo_with_upstream(tmpdir, repo):
+def repo_with_upstream(tmpdir, repo, default_git_branch):
     with open(os.path.join(repo.path, "second_file"), "w") as f:
         f.write("some data for the second file")
 
@@ -127,7 +145,7 @@ def repo_with_upstream(tmpdir, repo):
     upstream_location = None
 
     if repo.tool == "git":
-        upstream_location = "upstream/master"
+        upstream_location = f"upstream/{default_git_branch}"
         repo.run("remote", "add", "upstream", f"{tmpdir}/remoterepo")
         repo.run("fetch", "upstream")
         repo.run("branch", "--set-upstream-to", upstream_location)

test/test_util_vcs.py

@@ -10,8 +10,6 @@
 
 from taskgraph.util.vcs import HgRepository, Repository, get_repository
 
-from .fixtures.vcs import create_remote_repo
-
 
 def test_get_repository(repo):
     r = get_repository(repo.path)
@@ -159,14 +157,14 @@ def test_remote_name(repo_with_remote):
         assert repo.remote_name == remote_name
 
 
-def test_all_remote_names(tmpdir, repo_with_remote):
+def test_all_remote_names(tmpdir, create_remote_repo, repo_with_remote):
     repo, remote_name = repo_with_remote
     assert repo.all_remote_names == [remote_name]
     create_remote_repo(tmpdir, repo, "upstream2", "remote_path2")
     assert repo.all_remote_names == [remote_name, "upstream2"]
 
 
-def test_remote_name_many_remotes(tmpdir, repo_with_remote):
+def test_remote_name_many_remotes(tmpdir, create_remote_repo, repo_with_remote):
     repo, _ = repo_with_remote
     create_remote_repo(tmpdir, repo, "upstream2", "remote_path2")
 
@@ -177,7 +175,7 @@ def test_remote_name_many_remotes(tmpdir, repo_with_remote):
     assert repo.remote_name == "upstream"
 
 
-def test_remote_name_default_and_origin(tmpdir, repo_with_remote):
+def test_remote_name_default_and_origin(tmpdir, create_remote_repo, repo_with_remote):
     repo, _ = repo_with_remote
     remote_name = "origin" if repo.tool == "git" else "default"
     create_remote_repo(tmpdir, repo, remote_name, "remote_path2")
@@ -188,28 +186,28 @@ def test_remote_name_default_and_origin(tmpdir, repo_with_remote):
     assert repo.remote_name == remote_name
 
 
-def test_default_branch_guess(repo):
+def test_default_branch_guess(default_git_branch, repo):
     if repo.tool == "git":
-        assert repo.default_branch == "refs/heads/master"
+        assert repo.default_branch == f"refs/heads/{default_git_branch}"
     else:
         assert repo.default_branch == "default"
 
 
-def test_default_branch_remote_query(repo_with_remote):
+def test_default_branch_remote_query(default_git_branch, repo_with_remote):
     repo, _ = repo_with_remote
     if repo.tool == "git":
-        assert repo.default_branch == "upstream/master"
+        assert repo.default_branch == f"upstream/{default_git_branch}"
     else:
         assert repo.default_branch == "default"
 
 
-def test_default_branch_cloned_metadata(tmpdir, repo):
+def test_default_branch_cloned_metadata(tmpdir, default_git_branch, repo):
     if repo.tool == "git":
         clone_repo_path = tmpdir / "cloned_repo"
         command = ("git", "clone", repo.path, clone_repo_path)
         subprocess.check_output(command, cwd=tmpdir)
         cloned_repo = get_repository(clone_repo_path)
-        assert cloned_repo.default_branch == "origin/master"
+        assert cloned_repo.default_branch == f"origin/{default_git_branch}"
 
 
 def assert_files(actual, expected):