text: import fsspec
  import os
  import pytest
  import shutil
  import tempfile
  import subprocess
  
  pygit2 = pytest.importorskip("pygit2")
  
  
  @pytest.fixture()
  def repo():
      d = tempfile.mkdtemp()
      os.chdir(d)
      subprocess.call("git init", shell=True, cwd=d)
      subprocess.call("git init", shell=True, cwd=d)
      subprocess.call('git config user.email "you@example.com"', shell=True, cwd=d)
      subprocess.call('git config user.name "Your Name"', shell=True, cwd=d)
      open(os.path.join(d, "file1"), "wb").write(b"data0")
      subprocess.call("git add file1", shell=True, cwd=d)
      subprocess.call('git commit -m "init"', shell=True, cwd=d)
      sha = open(os.path.join(d, ".git/refs/heads/master"), "r").read().strip()
      open(os.path.join(d, "file1"), "wb").write(b"data00")
      subprocess.check_output('git commit -a -m "tagger"', shell=True, cwd=d)
      subprocess.call('git tag -a thetag -m "make tag"', shell=True, cwd=d)
      open(os.path.join(d, "file2"), "wb").write(b"data000")
      subprocess.call("git add file2", shell=True)
      subprocess.call('git commit -m "master tip"', shell=True, cwd=d)
      subprocess.call("git checkout -b abranch", shell=True, cwd=d)
      os.mkdir("inner")
      open(os.path.join(d, "inner", "file1"), "wb").write(b"data3")
      subprocess.call("git add inner/file1", shell=True, cwd=d)
      subprocess.call('git commit -m "branch tip"', shell=True, cwd=d)
      try:
          yield d, sha
      finally:
          shutil.rmtree(d)
  
  
  def test_refs(repo):
      d, sha = repo
      with fsspec.open("git://file1", path=d, ref=sha) as f:
          assert f.read() == b"data0"
  
      with fsspec.open("git://file1", path=d, ref="thetag") as f:
          assert f.read() == b"data00"
  
      with fsspec.open("git://file2", path=d, ref="master") as f:
          assert f.read() == b"data000"
  
      with fsspec.open("git://file2", path=d, ref=None) as f:
          assert f.read() == b"data000"
  
      with fsspec.open("git://inner/file1", path=d, ref="abranch") as f:
          assert f.read() == b"data3"
  