tests: setup user identity for tests

After a6413f5d a GitCommandError is raised.

Since there were no user identity were set up,
it fails:
 - ReviewableBranchTests from test_project.py
 - ResolveRepoRev and CheckRepoRev from test_wrapper.py

Test: ./run_tests
Change-Id: Id7f5772afe22c77fc4c8f8f0b8be1b627ed42187
Signed-off-by: Vitalii Dmitriev <vitalii.dmitriev@unikie.com>
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/398658
Reviewed-by: Mike Frysinger <vapier@google.com>
Tested-by: Vitalii Dmitriev <dmit.vitalii@gmail.com>
Commit-Queue: Vitalii Dmitriev <dmit.vitalii@gmail.com>
diff --git a/tests/conftest.py b/tests/conftest.py
index 3c31201..938051b 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -72,3 +72,12 @@
     the function scope.
     """
     return _set_home(monkeypatch, tmp_path_factory.mktemp("home"))
+
+
+@pytest.fixture(autouse=True)
+def setup_user_identity(monkeysession, scope="session"):
+    """Set env variables for author and committer name and email."""
+    monkeysession.setenv("GIT_AUTHOR_NAME", "Foo Bar")
+    monkeysession.setenv("GIT_COMMITTER_NAME", "Foo Bar")
+    monkeysession.setenv("GIT_AUTHOR_EMAIL", "foo@bar.baz")
+    monkeysession.setenv("GIT_COMMITTER_EMAIL", "foo@bar.baz")