rewrote test_gunzip to use a tempfolder instead of a tempfile, hoping it will fix Permission Errors on Travis Windows

also added a comment on the 'fz' format

Author: erwanp

astroquery/utils/system_tools.py

@@ -31,6 +31,7 @@ def gunzip(filename):
     # system-wide 'gzip' was removed, Python gzip used instead.
     # See #1538 : https://github.com/astropy/astroquery/issues/1538
 
+    # ".fz" denotes RICE rather than gzip compression
     if not filename.endswith('.fz'):
         with gzip.open(filename, 'rb') as f_in:
             with open(filename.rsplit(".", 1)[0], 'wb') as f_out:

astroquery/utils/tests/test_system_tools.py

@@ -2,10 +2,12 @@
 
 try:
     import gzip
+
     HAS_GZIP = True
 except ImportError:
     HAS_GZIP = False
 
+import shutil
 import os
 from os.path import exists
 import tempfile
@@ -15,30 +17,28 @@
 from ..system_tools import gunzip
 
 
-@pytest.mark.skipif('not HAS_GZIP')
+@pytest.mark.skipif("not HAS_GZIP")
 def test_gunzip():
-    filehandle = tempfile.NamedTemporaryFile(suffix='.txt.gz')
-    filename = filehandle.name
+
+    temp_dir = tempfile.mkdtemp()
+    filename = temp_dir + os.sep + "test_gunzip.txt.gz"
     unziped_filename = filename.rsplit(".", 1)[0]
-    for f in [filename, unziped_filename]:
-        if exists(f):
-            os.remove(f)
 
     # First create a gzip file
     content = b"Bla"
-    with gzip.open(filename, 'wb') as f:
+    with gzip.open(filename, "wb") as f:
         f.write(content)
 
-    # Then test our gunzip command works and creates an unziped file
-    gunzip(filename)
-    assert exists(unziped_filename)
+    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
+        # Check content is the same
+        with open(unziped_filename, "rb") as f:
+            new_content = f.read()
+        assert new_content == content
 
-    # Clean
-    for f in [filename, unziped_filename]:
-        if exists(f):
-            os.remove(f)
+    finally:
+        # Clean
+        shutil.rmtree(temp_dir)