diff --git a/tests/test_project.py b/tests/test_project.py
index 924a2459..02285e2f 100644
--- a/tests/test_project.py
+++ b/tests/test_project.py
@@ -26,6 +26,7 @@ import tempfile
 import unittest
 
 import error
+import git_command
 import git_config
 import platform_utils
 import project
@@ -38,7 +39,19 @@ def TempGitTree():
   # Python 2 support entirely.
   try:
     tempdir = tempfile.mkdtemp(prefix='repo-tests')
-    subprocess.check_call(['git', 'init'], cwd=tempdir)
+
+    # Tests need to assume, that main is default branch at init,
+    # which is not supported in config until 2.28.
+    cmd = ['git', 'init']
+    if git_command.git_require((2, 28, 0)):
+      cmd += ['--initial-branch=main']
+    else:
+      # Use template dir for init.
+      templatedir = tempfile.mkdtemp(prefix='.test-template')
+      with open(os.path.join(templatedir, 'HEAD'), 'w') as fp:
+        fp.write('ref: refs/heads/main\n')
+      cmd += ['--template=', templatedir]
+    subprocess.check_call(cmd, cwd=tempdir)
     yield tempdir
   finally:
     platform_utils.rmtree(tempdir)
diff --git a/tests/test_wrapper.py b/tests/test_wrapper.py
index d22dc4ee..069a5c3b 100644
--- a/tests/test_wrapper.py
+++ b/tests/test_wrapper.py
@@ -25,6 +25,7 @@ import shutil
 import tempfile
 import unittest
 
+import git_command
 import platform_utils
 from pyversion import is_python3
 import wrapper
@@ -357,7 +358,19 @@ class GitCheckoutTestCase(RepoWrapperTestCase):
 
     remote = os.path.join(cls.GIT_DIR, 'remote')
     os.mkdir(remote)
-    run_git('init', cwd=remote)
+
+    # Tests need to assume, that main is default branch at init,
+    # which is not supported in config until 2.28.
+    if git_command.git_require((2, 28, 0)):
+      initstr = '--initial-branch=main'
+    else:
+      # Use template dir for init.
+      templatedir = tempfile.mkdtemp(prefix='.test-template')
+      with open(os.path.join(templatedir, 'HEAD'), 'w') as fp:
+        fp.write('ref: refs/heads/main\n')
+      initstr = '--template=' + templatedir
+
+    run_git('init', initstr, cwd=remote)
     run_git('commit', '--allow-empty', '-minit', cwd=remote)
     run_git('branch', 'stable', cwd=remote)
     run_git('tag', 'v1.0', cwd=remote)