py27 compat fixes

src/pycalver/config.py

@@ -36,7 +36,7 @@ def parse_buffer(cfg_buffer: io.StringIO) -> MaybeConfig:
     cfg_parser = configparser.RawConfigParser()
     cfg_parser.readfp(cfg_buffer)
 
-    if "pycalver" not in cfg_parser:
+    if not cfg_parser.has_section("pycalver"):
         log.error("setup.cfg does not contain a [pycalver] section.")
         return None
 

test/test_config.py

@@ -25,7 +25,7 @@ def test_parse(tmpdir):
     setup_path = tmpdir.mkdir("minimal").join("setup.cfg")
     setup_path.write("\n".join((
         "[pycalver]",
-        f"current_version = v201808.0001-dev",
+        "current_version = v201808.0001-dev",
         "commit = False",
         "tag = False",
         "",
@@ -78,7 +78,7 @@ def test_parse_invalid_version(tmpdir):
     setup_path = tmpdir.mkdir("fail").join("setup.cfg")
     setup_path.write("\n".join((
         "[pycalver]",
-        f"current_version = 0.1.0",
+        "current_version = 0.1.0",
         "commit = False",
     )))
 

travis_run_tests.sh

@@ -2,6 +2,7 @@
 set -e
 
 # minimal test requirements for py27 testing
+python -m pip install -U pip
 python -m pip install pytest rst2html5
 
 rst2html5 --strict README.rst > /dev/null