From 80360c119e79f2282074aa6bd60bb54fd2d26d18 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Fri, 11 Dec 2020 09:29:41 +0000
Subject: [PATCH 01/10] add tests for opening PathLike objects

---
 pygac/tests/test_reader.py | 10 ++++++++++
 pygac/tests/test_utils.py  | 31 ++++++++++++++++++++++++++-----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/pygac/tests/test_reader.py b/pygac/tests/test_reader.py
index cec3451a..c27522c8 100644
--- a/pygac/tests/test_reader.py
+++ b/pygac/tests/test_reader.py
@@ -23,6 +23,7 @@
 import datetime
 import unittest
 import sys
+import os
 try:
     import mock
 except ImportError:
@@ -55,6 +56,15 @@ def test_filename(self):
         filepath = '/path/to/' + filename + '.gz'
         self.reader.filename = filepath
         self.assertEqual(self.reader.filename, filename)
+        self.reader.filename = None
+        self.assertIsNone(self.reader.filename)
+        class TestPath(os.PathLike):
+            def __init__(self, path):
+                self.path = str(path)
+            def __fspath__(self):
+                return self.path
+        self.reader.filename = TestPath(filepath)
+        self.assertEqual(self.reader.filename, filename)
 
     @unittest.skipIf(sys.version_info.major < 3, "Skipped in python2!")
     def test__read_scanlines(self):
diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 69d63383..79cbdf1e 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -28,6 +28,7 @@
 import gzip
 import sys
 import numpy as np
+import os
 try:
     from unittest import mock
 except ImportError:
@@ -37,10 +38,6 @@
                          calculate_sun_earth_distance_correction)
 
 
-def _raise_OSError(*args, **kwargs):
-    raise OSError
-
-
 class TestUtils(unittest.TestCase):
     """Test pygac.utils functions"""
 
@@ -68,7 +65,7 @@ def close(self):
         self.assertTrue(is_file_object(duck))
 
     @mock.patch('pygac.utils.open', mock.mock_open(read_data='file content'))
-    @mock.patch('pygac.utils.gzip.open', _raise_OSError)
+    @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
     def test_file_opener_1(self):
         """Test if a file is redirected correctly through file_opener."""
         with file_opener('path/to/file') as f:
@@ -98,6 +95,30 @@ def test_file_opener_2(self):
                 message = g.read()
         self.assertEqual(message, gzip_message_decoded)
 
+    @unittest.skipIf(sys.version_info.major < 3, "Not supported in python2!")
+    @mock.patch('pygac.utils.open', mock.MagicMock(side_effect=FileNotFoundError))
+    @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
+    def test_file_opener_3(self):
+        """Test file_opener with PathLike object"""
+        # prepare test
+        class RawBytes(os.PathLike):
+            def __init__(self, filename, raw_bytes):
+                self.filename = str(filename)
+                self.file_object = io.BytesIO(raw_bytes)
+
+            def __fspath__(self):
+                return self.filename
+
+            def open(self):
+                return self.file_object
+
+        filename = '/path/to/file'
+        file_bytes = b'TestTestTest'
+        test_pathlike = RawBytes(filename, file_bytes)
+        with file_opener(test_pathlike) as f:
+            content = f.read()
+        self.assertEqual(content, file_bytes)
+
     def test_calculate_sun_earth_distance_correction(self):
         """Test function for the sun distance corretction."""
         corr = calculate_sun_earth_distance_correction(3)

From 2c0506b02ace6aae5d12677a2df4befe4ee10638 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Fri, 11 Dec 2020 09:30:38 +0000
Subject: [PATCH 02/10] add capability to read PathLike objects with open
 method.

---
 pygac/reader.py | 1 +
 pygac/utils.py  | 9 ++++++++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/pygac/reader.py b/pygac/reader.py
index cfa6b7ce..79bcadbe 100644
--- a/pygac/reader.py
+++ b/pygac/reader.py
@@ -142,6 +142,7 @@ def filename(self, filepath):
         if filepath is None:
             self._filename = None
         else:
+            filepath = os.fspath(filepath)
             match = self.data_set_pattern.search(filepath)
             if match:
                 self._filename = match.group()
diff --git a/pygac/utils.py b/pygac/utils.py
index bb4e3c24..14ddda20 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -55,10 +55,17 @@ def _file_opener(file):
     Args:
         file - path to file or file object
     """
+    close = False
     # open file if necessary
     if is_file_object(file):
         open_file = file
-        close = False
+    elif hasattr(file, 'open'):
+        # use __enter__ to set the fileobject into context, this
+        # is needed to access the actual file object in fsspec
+        try:
+            open_file = file.open(mode='rb').__enter__()
+        except TypeError:
+            open_file = file.open().__enter__()
     else:
         open_file = open(file, mode='rb')
         close = True

From 2cf55aca7efe4f7f93e1e334462b067f500a4e15 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Fri, 11 Dec 2020 12:19:20 +0000
Subject: [PATCH 03/10] exit context when opening PathLike objects

---
 pygac/tests/test_utils.py | 17 +++++++++++++++--
 pygac/utils.py            | 15 ++++++++++-----
 2 files changed, 25 insertions(+), 7 deletions(-)

diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 79cbdf1e..221ae1ad 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -104,13 +104,13 @@ def test_file_opener_3(self):
         class RawBytes(os.PathLike):
             def __init__(self, filename, raw_bytes):
                 self.filename = str(filename)
-                self.file_object = io.BytesIO(raw_bytes)
+                self.raw_bytes = raw_bytes
 
             def __fspath__(self):
                 return self.filename
 
             def open(self):
-                return self.file_object
+                return io.BytesIO(self.raw_bytes)
 
         filename = '/path/to/file'
         file_bytes = b'TestTestTest'
@@ -118,6 +118,19 @@ def open(self):
         with file_opener(test_pathlike) as f:
             content = f.read()
         self.assertEqual(content, file_bytes)
+        
+        # test with lazy loading open method (open only in context)
+        class RawBytesLazy(RawBytes):
+            def open(self):
+                self.lazy_opener_mock = mock.MagicMock()
+                self.lazy_opener_mock.__enter__.return_value = io.BytesIO(self.raw_bytes)
+                return self.lazy_opener_mock
+            
+        test_pathlike = RawBytesLazy(filename, file_bytes)
+        with file_opener(test_pathlike) as f:
+            content = f.read()
+        self.assertEqual(content, file_bytes)
+        test_pathlike.lazy_opener_mock.__exit__.assert_called_once_with(None, None, None)
 
     def test_calculate_sun_earth_distance_correction(self):
         """Test function for the sun distance corretction."""
diff --git a/pygac/utils.py b/pygac/utils.py
index 14ddda20..2db65c3e 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -56,16 +56,19 @@ def _file_opener(file):
         file - path to file or file object
     """
     close = False
+    exit = False
     # open file if necessary
     if is_file_object(file):
         open_file = file
     elif hasattr(file, 'open'):
-        # use __enter__ to set the fileobject into context, this
-        # is needed to access the actual file object in fsspec
         try:
-            open_file = file.open(mode='rb').__enter__()
+            _open_file = file.open(mode='rb')
         except TypeError:
-            open_file = file.open().__enter__()
+            _open_file = file.open()
+        # use __enter__ to set the fileobject into context, this
+        # is needed to access the actual file object in fsspec
+        open_file = _open_file.__enter__()
+        exit = True
     else:
         open_file = open(file, mode='rb')
         close = True
@@ -82,7 +85,9 @@ def _file_opener(file):
         yield file_object
     finally:
         if close:
-            file_object.close()
+            open_file.close()
+        if exit:
+            _open_file.__exit__(None, None, None)
 
 
 @contextmanager

From 414f3666ca45851f7e890246dfc8fd7e944384b2 Mon Sep 17 00:00:00 2001
From: stickler-ci <support@stickler-ci.com>
Date: Fri, 11 Dec 2020 12:25:51 +0000
Subject: [PATCH 04/10] Fixing style errors.

---
 pygac/tests/test_reader.py | 2 ++
 pygac/tests/test_utils.py  | 4 ++--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/pygac/tests/test_reader.py b/pygac/tests/test_reader.py
index c27522c8..7b35e875 100644
--- a/pygac/tests/test_reader.py
+++ b/pygac/tests/test_reader.py
@@ -58,9 +58,11 @@ def test_filename(self):
         self.assertEqual(self.reader.filename, filename)
         self.reader.filename = None
         self.assertIsNone(self.reader.filename)
+
         class TestPath(os.PathLike):
             def __init__(self, path):
                 self.path = str(path)
+
             def __fspath__(self):
                 return self.path
         self.reader.filename = TestPath(filepath)
diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 221ae1ad..17a44e46 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -118,14 +118,14 @@ def open(self):
         with file_opener(test_pathlike) as f:
             content = f.read()
         self.assertEqual(content, file_bytes)
-        
+
         # test with lazy loading open method (open only in context)
         class RawBytesLazy(RawBytes):
             def open(self):
                 self.lazy_opener_mock = mock.MagicMock()
                 self.lazy_opener_mock.__enter__.return_value = io.BytesIO(self.raw_bytes)
                 return self.lazy_opener_mock
-            
+
         test_pathlike = RawBytesLazy(filename, file_bytes)
         with file_opener(test_pathlike) as f:
             content = f.read()

From 2a75d3c3966bb6b9959d2662dca9859ce23f68d5 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Fri, 11 Dec 2020 13:14:14 +0000
Subject: [PATCH 05/10] update stickler to read python 3

---
 .stickler.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/.stickler.yml b/.stickler.yml
index 4a6f4e14..e5e6fe74 100644
--- a/.stickler.yml
+++ b/.stickler.yml
@@ -1,6 +1,7 @@
 linters:
   flake8:
     fixer: true
-    max-line-length: 120
+    python: 3
+    config: setup.cfg
 fixers:
   enable: true

From e86352f2e2b3d972668b3d3259a3713604dac0d9 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Fri, 11 Dec 2020 13:22:42 +0000
Subject: [PATCH 06/10] set required python version to >=3.6

---
 setup.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index 1b685864..f0f00d6f 100644
--- a/setup.py
+++ b/setup.py
@@ -74,6 +74,6 @@
                       ('gapfilled_tles', ['gapfilled_tles/TLE_noaa16.txt'])],
           test_suite="pygac.tests.suite",
           tests_require=[],
-          python_requires='>=2.7,!=3.0.*,!=3.1.*,!=3.2.*,!=3.3.*',
+          python_requires='>=3.6',
           zip_safe=False
           )

From 4769a9408af846d26f8c8a4efc695c944455c486 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Mon, 14 Dec 2020 10:46:06 +0000
Subject: [PATCH 07/10] remove obsolete test.

---
 pygac/tests/test_utils.py |  26 +--------
 pygac/utils.py            | 112 +++++++-------------------------------
 2 files changed, 22 insertions(+), 116 deletions(-)

diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 17a44e46..44473a1e 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -34,8 +34,7 @@
 except ImportError:
     import mock
 
-from pygac.utils import (is_file_object, file_opener,
-                         calculate_sun_earth_distance_correction)
+from pygac.utils import file_opener, calculate_sun_earth_distance_correction
 
 
 class TestUtils(unittest.TestCase):
@@ -43,27 +42,6 @@ class TestUtils(unittest.TestCase):
 
     longMessage = True
 
-    def test_is_file_object(self):
-        """Test is_file_object function."""
-        # true test
-        with io.BytesIO(b'file content') as fileobj:
-            self.assertTrue(is_file_object(fileobj))
-        # false test
-        self.assertFalse(is_file_object("test.txt"))
-        # duck type test
-
-        class Duck(object):
-            def read(self, n):
-                return n*b'\00'
-
-            def seekable(self):
-                return True
-
-            def close(self):
-                pass
-        duck = Duck()
-        self.assertTrue(is_file_object(duck))
-
     @mock.patch('pygac.utils.open', mock.mock_open(read_data='file content'))
     @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
     def test_file_opener_1(self):
@@ -72,7 +50,6 @@ def test_file_opener_1(self):
             content = f.read()
         self.assertEqual(content, 'file content')
 
-    @unittest.skipIf(sys.version_info.major < 3, "Not supported in python2!")
     def test_file_opener_2(self):
         """Test file_opener with file objects and compression"""
         # prepare test
@@ -95,7 +72,6 @@ def test_file_opener_2(self):
                 message = g.read()
         self.assertEqual(message, gzip_message_decoded)
 
-    @unittest.skipIf(sys.version_info.major < 3, "Not supported in python2!")
     @mock.patch('pygac.utils.open', mock.MagicMock(side_effect=FileNotFoundError))
     @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
     def test_file_opener_3(self):
diff --git a/pygac/utils.py b/pygac/utils.py
index 2db65c3e..4bb8f397 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -20,59 +20,19 @@
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 import gzip
+import io
 import logging
-import numpy as np
 import sys
-from contextlib import contextmanager
-
-LOG = logging.getLogger(__name__)
 
+from contextlib import contextmanager, nullcontext
 
-def is_file_object(filename):
-    """Check if the input is a file object.
-
-    Args:
-        filename - object to check
+import numpy as np
 
-    Note:
-        This method only check if the object implements the
-        interface of a file object to allow duck types like
-        gzip.GzipFile instances.
-    """
-    has_close = hasattr(filename, 'close')
-    has_read = hasattr(filename, 'read')
-    if hasattr(filename, 'seekable'):
-        is_seekable = filename.seekable()
-    else:
-        is_seekable = False
-    return has_close and has_read and is_seekable
+LOG = logging.getLogger(__name__)
 
 
-@contextmanager
-def _file_opener(file):
-    """Open a file depending on the input.
-
-    Args:
-        file - path to file or file object
-    """
-    close = False
-    exit = False
-    # open file if necessary
-    if is_file_object(file):
-        open_file = file
-    elif hasattr(file, 'open'):
-        try:
-            _open_file = file.open(mode='rb')
-        except TypeError:
-            _open_file = file.open()
-        # use __enter__ to set the fileobject into context, this
-        # is needed to access the actual file object in fsspec
-        open_file = _open_file.__enter__()
-        exit = True
-    else:
-        open_file = open(file, mode='rb')
-        close = True
-    # check if it is a gzip file
+def gzip_inspected(open_file):
+    """Try to gzip decompress the file object if applicable."""
     try:
         file_object = gzip.open(open_file)
         file_object.read(1)
@@ -80,53 +40,23 @@ def _file_opener(file):
         file_object = open_file
     finally:
         file_object.seek(0)
-    # provide file_object with the context
-    try:
-        yield file_object
-    finally:
-        if close:
-            open_file.close()
-        if exit:
-            _open_file.__exit__(None, None, None)
-
+    return file_object
 
 @contextmanager
-def _file_opener_py2(file):
-    """Open a file depending on the input.
-
-    Args:
-        file - path to file
-    """
-    close = True
-    # check if it is a gzip file
-    try:
-        file_object = gzip.open(file)
-        file_object.read(1)
-    # Note: in python 2, this is an IOError, but we keep the
-    #       OSError for testing.
-    except (OSError, IOError):
-        file_object = open(file, mode='rb')
-    except TypeError:
-        # In python 2 gzip.open cannot handle file objects
-        LOG.debug("Gzip cannot open file objects in python2!")
-        if is_file_object(file):
-            file_object = file
-            close = False
-    finally:
-        file_object.seek(0)
-    # provide file_object with the context
-    try:
-        yield file_object
-    finally:
-        if close:
-            file_object.close()
-
-
-if sys.version_info.major < 3:
-    file_opener = _file_opener_py2
-else:
-    file_opener = _file_opener
-
+def file_opener(file):
+    if isinstance(file, io.IOBase) and file.seekable():
+        # avoid closing the file using nullcontext
+        open_file = nullcontext(file)
+    elif hasattr(file, 'open'):
+        try:
+            open_file = file.open(mode='rb')
+        except TypeError:
+            open_file = file.open()
+    else:
+        open_file = open(file, mode='rb')
+    # set open_file into context in case of lazy loding in __enter__ method.
+    with open_file as file_object:
+        yield gzip_inspected(file_object)
 
 def get_absolute_azimuth_angle_diff(sat_azi, sun_azi):
     """Calculates absolute azimuth difference angle. """

From c62b8f3e9cf650b0f9e1ef2626f7201c3637dac0 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Mon, 14 Dec 2020 11:39:52 +0000
Subject: [PATCH 08/10] remove unused imports

---
 pygac/tests/test_utils.py | 13 +++++--------
 pygac/utils.py            |  1 -
 2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 44473a1e..7bf9c220 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -23,16 +23,13 @@
 """Test pygac.utils module
 """
 
-import unittest
-import io
 import gzip
-import sys
-import numpy as np
+import io
 import os
-try:
-    from unittest import mock
-except ImportError:
-    import mock
+import unittest
+from unittest import mock
+
+import numpy as np
 
 from pygac.utils import file_opener, calculate_sun_earth_distance_correction
 
diff --git a/pygac/utils.py b/pygac/utils.py
index 4bb8f397..614ad498 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -22,7 +22,6 @@
 import gzip
 import io
 import logging
-import sys
 
 from contextlib import contextmanager, nullcontext
 

From 74deb240e146304b8a3c95f615208af1c7888aa3 Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Mon, 14 Dec 2020 13:42:54 +0000
Subject: [PATCH 09/10] clean code and remove unused mock in file opener test

---
 pygac/tests/test_utils.py | 6 ++----
 pygac/utils.py            | 6 ++++--
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/pygac/tests/test_utils.py b/pygac/tests/test_utils.py
index 7bf9c220..8c632c80 100644
--- a/pygac/tests/test_utils.py
+++ b/pygac/tests/test_utils.py
@@ -39,13 +39,12 @@ class TestUtils(unittest.TestCase):
 
     longMessage = True
 
-    @mock.patch('pygac.utils.open', mock.mock_open(read_data='file content'))
-    @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
+    @mock.patch('pygac.utils.open', mock.MagicMock(return_value=io.BytesIO(b'file content')))
     def test_file_opener_1(self):
         """Test if a file is redirected correctly through file_opener."""
         with file_opener('path/to/file') as f:
             content = f.read()
-        self.assertEqual(content, 'file content')
+        self.assertEqual(content, b'file content')
 
     def test_file_opener_2(self):
         """Test file_opener with file objects and compression"""
@@ -70,7 +69,6 @@ def test_file_opener_2(self):
         self.assertEqual(message, gzip_message_decoded)
 
     @mock.patch('pygac.utils.open', mock.MagicMock(side_effect=FileNotFoundError))
-    @mock.patch('pygac.utils.gzip.open', mock.MagicMock(side_effect=OSError))
     def test_file_opener_3(self):
         """Test file_opener with PathLike object"""
         # prepare test
diff --git a/pygac/utils.py b/pygac/utils.py
index 614ad498..fd6daccc 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -33,14 +33,15 @@
 def gzip_inspected(open_file):
     """Try to gzip decompress the file object if applicable."""
     try:
-        file_object = gzip.open(open_file)
-        file_object.read(1)
+        file_object = gzip.GzipFile(mode='rb', fileobj=open_file)
+        file_object.read1()
     except OSError:
         file_object = open_file
     finally:
         file_object.seek(0)
     return file_object
 
+
 @contextmanager
 def file_opener(file):
     if isinstance(file, io.IOBase) and file.seekable():
@@ -57,6 +58,7 @@ def file_opener(file):
     with open_file as file_object:
         yield gzip_inspected(file_object)
 
+
 def get_absolute_azimuth_angle_diff(sat_azi, sun_azi):
     """Calculates absolute azimuth difference angle. """
     rel_azi = abs(sat_azi - sun_azi)

From 166cbbd157b326326acb7b1e65e45af0070b374f Mon Sep 17 00:00:00 2001
From: horn <carlos.horn@external.eumetsat.int>
Date: Tue, 15 Dec 2020 16:18:55 +0000
Subject: [PATCH 10/10] fix gzip inspect and correct typo

---
 pygac/utils.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/pygac/utils.py b/pygac/utils.py
index fd6daccc..76a7fd9e 100644
--- a/pygac/utils.py
+++ b/pygac/utils.py
@@ -34,7 +34,7 @@ def gzip_inspected(open_file):
     """Try to gzip decompress the file object if applicable."""
     try:
         file_object = gzip.GzipFile(mode='rb', fileobj=open_file)
-        file_object.read1()
+        file_object.read(1)
     except OSError:
         file_object = open_file
     finally:
@@ -54,7 +54,7 @@ def file_opener(file):
             open_file = file.open()
     else:
         open_file = open(file, mode='rb')
-    # set open_file into context in case of lazy loding in __enter__ method.
+    # set open_file into context in case of lazy loading in __enter__ method.
     with open_file as file_object:
         yield gzip_inspected(file_object)