Make code compatible with legacy Python

Author: gahjelle

reader/__main__.py

@@ -3,7 +3,7 @@
 Usage:
 ------
 
-    $ realpython [options] [<id>]
+    $ realpython [options] [id] [id ...]
 
 List the latest tutorials:
 
@@ -44,7 +44,7 @@
 from reader import viewer
 
 
-def main() -> None:
+def main():  # type: () -> 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("-")]
@@ -55,7 +55,7 @@ def main() -> None:
         return
 
     # Should links be shown in the text
-    show_links = ("-l" in opts or "--show-links" in opts)
+    show_links = "-l" in opts or "--show-links" in opts
 
     # An article ID is given, show article
     if args:

reader/feed.py

@@ -1,38 +1,39 @@
 """Interact with the Real Python feed"""
 # Standard library imports
-from typing import Dict, List
+from typing import Dict, List  # noqa
 
 # Third party imports
 import feedparser
 import html2text
 
 # Reader imports
 from reader import URL
-_CACHED_FEEDS: Dict[str, feedparser.FeedParserDict] = dict()
 
+_CACHED_FEEDS = dict()  # type: Dict[str, feedparser.FeedParserDict]
 
-def _feed() -> feedparser.FeedParserDict:
+
+def _feed():  # type: () -> 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() -> str:
+def get_site():  # type: () -> str
     """Get name and link to web site of the feed"""
     info = _feed().feed
-    return f"{info.title} ({info.link})"
+    return "{info.title} ({info.link})".format(info=info)
 
 
-def get_article(article_id: str, links: bool = False) -> str:
+def get_article(article_id, links=False):  # type: (str, bool) -> str
     """Get article from feed with the given ID"""
     articles = _feed().entries
     try:
         article = articles[int(article_id)]
     except (IndexError, ValueError):
         max_id = len(articles) - 1
-        msg = f"Unknown article ID, use ID from 0 to {max_id}"
-        raise SystemExit(f"Error: {msg}")
+        msg = "Unknown article ID, use ID from 0 to {}".format(max_id)
+        raise SystemExit("Error: {}".format(msg))
 
     # Get article as HTML
     try:
@@ -45,10 +46,10 @@ def get_article(article_id: str, links: bool = False) -> str:
     to_text.ignore_links = not links
     text = to_text.handle(html)
 
-    return f"# {article.title}\n\n{text}"
+    return u"# {}\n\n{}".format(article.title, text)
 
 
-def get_titles() -> List[str]:
+def get_titles():  # type: () -> List[str]
     """List titles in feed"""
     articles = _feed().entries
     return [a.title for a in articles]

reader/viewer.py

@@ -1,16 +1,19 @@
 """Functions for displaying the Real Python feed"""
 
+# Support Python 2
+from __future__ import print_function
+
 # Standard library imports
-from typing import List
+from typing import List  # noqa
 
 
-def show(article: str) -> None:
+def show(article):  # type: (str) -> None
     """Show one article"""
     print(article)
 
 
-def show_list(site: str, titles: List[str]) -> None:
+def show_list(site, titles):  # type: (str, List[str]) -> None
     """Show list of articles"""
-    print(f"The latest tutorials from {site}")
+    print("The latest tutorials from {}".format(site))
     for article_id, title in enumerate(titles):
-        print(f"{article_id:>3} {title}")
+        print("{:>3} {}".format(article_id, title))

setup.py

@@ -24,13 +24,10 @@
     classifiers=[
         "License :: OSI Approved :: MIT License",
         "Programming Language :: Python",
+        "Programming Language :: Python :: 2",
         "Programming Language :: Python :: 3",
     ],
     packages=["reader"],
-    install_requires=["feedparser", "html2text"],
-    entry_points={
-        "console_scripts": [
-            "realpython=reader.__main__:main",
-        ]
-    },
+    install_requires=["feedparser", "html2text", "typing"],
+    entry_points={"console_scripts": ["realpython=reader.__main__:main"]},
 )

tests/test_feed.py

@@ -1,6 +1,6 @@
 """Tests for the reader.feed module"""
 # Standard library imports
-import pathlib
+import os.path
 
 # Third party imports
 import pytest
@@ -9,21 +9,21 @@
 from reader import feed
 
 # Current directory
-HERE = pathlib.Path(__file__).parent
+HERE = os.path.dirname(__file__)
 
 
 @pytest.fixture
 def monkeypatch_feed(monkeypatch):
     """Use local file instead of downloading feed from web"""
-    local_path = HERE / "realpython_20180919.xml"
+    local_path = os.path.join(HERE, "realpython_20180919.xml")
     monkeypatch.setattr(feed, "URL", local_path)
     return local_path
 
 
 @pytest.fixture
 def monkeypatch_summary_feed(monkeypatch):
     """Use local file instead of downloading feed from web"""
-    local_path = HERE / "realpython_descriptions_20180919.xml"
+    local_path = os.path.join(HERE, "realpython_descriptions_20180919.xml")
     monkeypatch.setattr(feed, "URL", local_path)
     return local_path
 

tests/test_viewer.py

@@ -30,11 +30,11 @@ def test_show_list(capsys):
     assert stderr == ""
 
     # Site name is shown in header
-    header, *lines = stdout.split("\n")
-    assert site in header
+    lines = stdout.split("\n")
+    assert site in lines[0]
 
     # Each thing is listed preceded by a number
-    for thing, line in zip(things, lines):
-        line_id, *_ = line.split()
-        assert line_id.isnumeric()
+    for thing, line in zip(things, lines[1:]):
+        line_parts = line.split()
+        assert line_parts[0].isnumeric()
         assert thing in line