Refactor utils/tests/test_system_tools.py

1. There is no need to check for the availability of `gzip` because it
   is in the Python standard library.
2. There is no need to write code for managing temporary directories
   because `pytest` provides the `tmp_path` fixture.
3. A separate test for checking the existance of a file produced by the
   tests is not needed because if it does not exist the following tests
   fail anyways.

Author: eerovaher

astroquery/utils/tests/test_system_tools.py

@@ -1,44 +1,18 @@
 # Licensed under a 3-clause BSD style license - see LICENSE.rst
 
-try:
-    import gzip
-
-    HAS_GZIP = True
-except ImportError:
-    HAS_GZIP = False
-
-import shutil
-import os
-from os.path import exists
-import tempfile
-
-import pytest
+import gzip
 
 from ..system_tools import gunzip
 
 
-@pytest.mark.skipif("not HAS_GZIP")
-def test_gunzip():
-
-    temp_dir = tempfile.mkdtemp()
-    filename = f"{temp_dir}{os.sep}test_gunzip.txt.gz"
-    unziped_filename = filename.rsplit(".", 1)[0]
-
+def test_gunzip(tmp_path):
+    filename = tmp_path / 'test_gunzip.txt.gz'
     # First create a gzip file
     content = b"Bla"
     with gzip.open(filename, "wb") as f:
         f.write(content)
-
-    try:
-        # Then test our gunzip command works and creates an unziped file
-        gunzip(filename)
-        assert exists(unziped_filename)
-
-        # Check content is the same
-        with open(unziped_filename, "rb") as f:
-            new_content = f.read()
-        assert new_content == content
-
-    finally:
-        # Clean
-        shutil.rmtree(temp_dir)
+    # Then test our gunzip command works
+    gunzip(str(filename))
+    with open(filename.with_suffix(''), "rb") as f:
+        new_content = f.read()
+    assert new_content == content