Upgrade to Python 3.7 and above (realpython#12)

gahjelle · web-flow · commit 0387003b4eeb · 2021-10-14T12:46:12.000+02:00
* Reformat with Black

* Reformat with Isort

* Add f-strings and proper type hints

* Make docstrings PEP257 compatible
diff --git a/README.md b/README.md
@@ -8,13 +8,13 @@ For more information see the tutorial [How to Publish an Open-Source Python Pack
 
 You can install the Real Python Feed Reader from [PyPI](https://pypi.org/project/realpython-reader/):
 
-    pip install realpython-reader
+    python -m pip install realpython-reader
 
-The reader is supported on Python 2.7, as well as Python 3.4 and above.
+The reader is supported on Python 3.7 and above. Older versions of Python, including Python 2.7, are supported by version 1.0.0 of the reader.
 
 ## How to use
 
-The Real Python Feed Reader is a command line application, named `realpython`. To see a list of the [latest Real Python tutorials](https://realpython.com/) simply call the program:
+The Real Python Feed Reader is a command line application, named `realpython`. To see a list of the [latest Real Python tutorials](https://realpython.com/), call the program without any arguments:
 
     $ realpython
     The latest tutorials from Real Python (https://realpython.com/)
@@ -62,4 +62,3 @@ You can also call the Real Python Feed Reader in your own Python code, by import
     >>> from reader import feed
     >>> feed.get_titles()
     ['How to Publish an Open-Source Python Package to PyPI', ...]
-
diff --git a/reader/__init__.py b/reader/__init__.py
@@ -1,25 +1,22 @@
-"""Real Python feed reader
+"""Real Python feed reader.
 
 Import the `feed` module to work with the Real Python feed:
 
     >>> from reader import feed
     >>> feed.get_titles()
     ['Logging in Python', 'The Best Python Books', ...]
 
-See https://github.com/realpython/reader/ for more information
+See https://github.com/realpython/reader/ for more information.
 """
-import importlib_resources as _resources
-try:
-    from configparser import ConfigParser as _ConfigParser
-except ImportError:  # Python 2
-    from ConfigParser import ConfigParser as _ConfigParser
-
+from configparser import ConfigParser
+from importlib import resources
 
 # Version of realpython-reader package
 __version__ = "1.0.0"
 
 # Read URL of feed from config file
-_cfg = _ConfigParser()
-with _resources.path("reader", "config.cfg") as _path:
-    _cfg.read(str(_path))
-URL = _cfg.get("feed", "url")
+cfg = ConfigParser()
+with resources.path("reader", "config.cfg") as path:
+    cfg.read(str(path))
+
+URL = cfg.get("feed", "url")
diff --git a/reader/__main__.py b/reader/__main__.py
@@ -1,4 +1,4 @@
-"""Read the latest Real Python tutorials
+"""Read the latest Real Python tutorials.
 
 Usage:
 ------
@@ -47,19 +47,18 @@
 
 # Reader imports
 import reader
-from reader import feed
-from reader import viewer
+from reader import feed, viewer
 
 
-def main():  # type: () -> None
-    """Read the Real Python article feed"""
+def main() -> None:
+    """Read the Real Python article feed."""
     args = [a for a in sys.argv[1:] if not a.startswith("-")]
     opts = [o for o in sys.argv[1:] if o.startswith("-")]
 
     # Show help message
     if "-h" in opts or "--help" in opts:
         viewer.show(__doc__)
-        return
+        raise SystemExit()
 
     # Should links be shown in the text
     show_links = "-l" in opts or "--show-links" in opts
diff --git a/reader/feed.py b/reader/feed.py
@@ -1,4 +1,4 @@
-"""Interact with the Real Python feed"""
+"""Interact with the Real Python feed."""
 # Standard library imports
 from typing import Dict, List  # noqa
 
@@ -9,32 +9,31 @@
 # Reader imports
 from reader import URL
 
-_CACHED_FEEDS = dict()  # type: Dict[str, feedparser.FeedParserDict]
+_CACHED_FEEDS: Dict[str, feedparser.FeedParserDict] = {}
 
 
-def _feed(url=URL):  # type: (str) -> feedparser.FeedParserDict
-    """Cache contents of the feed, so it's only read once"""
+def _feed(url: str = URL) -> feedparser.FeedParserDict:
+    """Cache contents of the feed, so it's only read once."""
     if url not in _CACHED_FEEDS:
         _CACHED_FEEDS[url] = feedparser.parse(url)
     return _CACHED_FEEDS[url]
 
 
-def get_site(url=URL):  # type: (str) -> str
-    """Get name and link to web site of the feed"""
+def get_site(url: str = URL) -> str:
+    """Get name and link to web site of the feed."""
     info = _feed(url).feed
-    return u"{info.title} ({info.link})".format(info=info)
+    return f"{info.title} ({info.link})"
 
 
-def get_article(article_id, links=False, url=URL):
-    # type: (str, bool, str) -> str
-    """Get article from feed with the given ID"""
+def get_article(article_id: str, links: bool = False, url: str = URL) -> str:
+    """Get article from feed with the given ID."""
     articles = _feed(url).entries
     try:
         article = articles[int(article_id)]
     except (IndexError, ValueError):
         max_id = len(articles) - 1
-        msg = "Unknown article ID, use ID from 0 to {}".format(max_id)
-        raise SystemExit("Error: {}".format(msg))
+        msg = f"Unknown article ID, use ID from 0 to {max_id}"
+        raise SystemExit(f"Error: {msg}")
 
     # Get article as HTML
     try:
@@ -47,10 +46,10 @@ def get_article(article_id, links=False, url=URL):
     to_text.ignore_links = not links
     text = to_text.handle(html)
 
-    return u"# {}\n\n{}".format(article.title, text)
+    return f"# {article.title}\n\n{text}"
 
 
-def get_titles(url=URL):  # type: (str) -> List[str]
-    """List titles in feed"""
+def get_titles(url: str = URL) -> List[str]:
+    """List titles in feed."""
     articles = _feed(url).entries
     return [a.title for a in articles]
diff --git a/reader/viewer.py b/reader/viewer.py
@@ -1,19 +1,16 @@
-"""Functions for displaying the Real Python feed"""
-
-# Support Python 2
-from __future__ import print_function
+"""Functions for displaying the Real Python feed."""
 
 # Standard library imports
-from typing import List  # noqa
+from typing import List
 
 
-def show(article):  # type: (str) -> None
-    """Show one article"""
+def show(article: str) -> None:
+    """Show one article."""
     print(article)
 
 
-def show_list(site, titles):  # type: (str, List[str]) -> None
-    """Show list of articles"""
-    print(u"The latest tutorials from {}".format(site))
+def show_list(site: str, titles: List[str]) -> None:
+    """Show list of articles."""
+    print(f"The latest tutorials from {site}")
     for article_id, title in enumerate(titles):
-        print(u"{:>3} {}".format(article_id, title))
+        print(f"{article_id:>3} {title}")
diff --git a/setup.cfg b/setup.cfg
@@ -0,0 +1,5 @@
+[mypy]
+strict = True
+
+[mypy-feedparser.*]
+ignore_missing_imports = True
diff --git a/setup.py b/setup.py
@@ -1,14 +1,16 @@
 """Setup script for realpython-reader"""
 
-import os.path
+# Standard library imports
+import pathlib
+
+# Third party imports
 from setuptools import setup
 
 # The directory containing this file
-HERE = os.path.abspath(os.path.dirname(__file__))
+HERE = pathlib.Path(__file__).resolve().parent
 
-# The text of the README file
-with open(os.path.join(HERE, "README.md")) as fid:
-    README = fid.read()
+# The text of the README file is used as a description
+README = (HERE / "README.md").read_text()
 
 # This call to setup() does all the work
 setup(
@@ -24,13 +26,10 @@
     classifiers=[
         "License :: OSI Approved :: MIT License",
         "Programming Language :: Python",
-        "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 3",
     ],
     packages=["reader"],
     include_package_data=True,
-    install_requires=[
-        "feedparser", "html2text", "importlib_resources", "typing"
-    ],
+    install_requires=["feedparser", "html2text"],
     entry_points={"console_scripts": ["realpython=reader.__main__:main"]},
 )
diff --git a/tests/test_feed.py b/tests/test_feed.py
@@ -1,6 +1,6 @@
-"""Tests for the reader.feed module"""
+"""Tests for the reader.feed module."""
 # Standard library imports
-import os.path
+import pathlib
 
 # Third party imports
 import pytest
@@ -9,32 +9,32 @@
 from reader import feed
 
 # Current directory
-HERE = os.path.dirname(__file__)
+HERE = pathlib.Path(__file__).resolve().parent
 
 
 @pytest.fixture
 def local_feed():
-    """Use local file instead of downloading feed from web"""
-    return os.path.join(HERE, "realpython_20180919.xml")
+    """Use local file instead of downloading feed from web."""
+    return HERE / "realpython_20180919.xml"
 
 
 @pytest.fixture
 def local_summary_feed():
-    """Use local file instead of downloading feed from web"""
-    return os.path.join(HERE, "realpython_descriptions_20180919.xml")
+    """Use local file instead of downloading feed from web."""
+    return HERE / "realpython_descriptions_20180919.xml"
 
 
 #
 # Tests
 #
 def test_site(local_feed):
-    """Test that we can read the site title and link"""
+    """Test that we can read the site title and link."""
     expected = "Real Python (https://realpython.com/)"
     assert feed.get_site(url=local_feed) == expected
 
 
 def test_article_title(local_feed):
-    """Test that title is added at top of article"""
+    """Test that title is added at top of article."""
     article_id = 0
     title = feed.get_titles(url=local_feed)[article_id]
     article = feed.get_article(article_id, url=local_feed)
@@ -43,7 +43,7 @@ def test_article_title(local_feed):
 
 
 def test_article(local_feed):
-    """Test that article is returned"""
+    """Test that article is returned."""
     article_id = 2
     article_phrases = [
         "logging.info('This is an info message')",
@@ -57,7 +57,7 @@ def test_article(local_feed):
 
 
 def test_titles(local_feed):
-    """Test that titles are found"""
+    """Test that titles are found."""
     titles = feed.get_titles(url=local_feed)
 
     assert len(titles) == 20
@@ -66,7 +66,7 @@ def test_titles(local_feed):
 
 
 def test_summary(local_summary_feed):
-    """Test that summary feeds can be read"""
+    """Test that summary feeds can be read."""
     article_id = 1
     summary_phrases = [
         "Get the inside scoop",
@@ -79,7 +79,7 @@ def test_summary(local_summary_feed):
 
 
 def test_invalid_article_id(local_feed):
-    """Test that invalid article ids are handled gracefully"""
+    """Test that invalid article ids are handled gracefully."""
     article_id = "wrong"
     with pytest.raises(SystemExit):
         feed.get_article(article_id, url=local_feed)
diff --git a/tests/test_viewer.py b/tests/test_viewer.py
@@ -1,7 +1,4 @@
-"""Tests for the reader.viewer module"""
-
-# Third party imports
-import pytest
+"""Tests for the reader.viewer module."""
 
 # Reader imports
 from reader import viewer
@@ -11,7 +8,7 @@
 # Tests
 #
 def test_show(capsys):
-    """Test that show adds information to stdout"""
+    """Test that show adds information to stdout."""
     text = "Lorem ipsum dolor sit amet"
     viewer.show(text)
     stdout, stderr = capsys.readouterr()
@@ -22,7 +19,7 @@ def test_show(capsys):
 
 
 def test_show_list(capsys):
-    """Test that show_list shows a list of items with an ID"""
+    """Test that show_list shows a list of items with an ID."""
     site = "Real Python"
     things = ["pathlib", "data classes", "python 3.7", "decorators"]
     viewer.show_list(site, things)
