refactor: Improve readability

plug/pip_resolve.py

@@ -19,6 +19,8 @@
         raise ImportError(
             "Could not import pkg_resources; please install setuptools or pip.")
 
+PYTHON_MARKER_REGEX = 'python_version\s*(?P<operator>==|<=|=>|>|<)\s*\'(?P<python_version>.+)\''
+SYSTEM_MARKER_REGEX = 'sys_platform\s*==\s*[\'"](.+)[\'"]'
 
 def create_tree_of_packages_dependencies(dist_tree, packages_names, req_file_path, allow_missing=False):
     """Create packages dependencies tree
@@ -97,10 +99,7 @@ def create_package_as_root(package, dir_as_root):
         dir_as_root[DEPENDENCIES][package_as_root[NAME]] = package_tree
     return dir_as_root
 
-sys_platform_re = re.compile('sys_platform\s*==\s*[\'"](.+)[\'"]')
-sys_platform = sys.platform.lower()
-
-def satisfies_python_requirement(parsed_operator, parsed_python_version ):
+def satisfies_python_requirement(parsed_operator, parsed_python_version):
     # TODO: use python semver library to compare versions
     operator_func = {
         ">": gt,
@@ -111,35 +110,39 @@ def satisfies_python_requirement(parsed_operator, parsed_python_version ):
         '!=': ne,
     }[parsed_operator]
     system_python = str(sys.version_info[0]) + '.' + str(sys.version_info[1])
-    satisfies = operator_func(float(system_python), float(parsed_python_version))
-    return satisfies
+    return operator_func(float(system_python), float(parsed_python_version))
 
-def matches_python_version(requirement):
-    """Filter out requirements that should not be installed
-    in this Python version.
-    See: https://www.python.org/dev/peps/pep-0508/#environment-markers
-    """
-    python_version_re = re.compile('python_version\s*(==|<=|=>|>|<)\s*\'(.+)\'')
+def get_markers_text(requirement):
     if isinstance(requirement, pipfile.PipfileRequirement):
         markers_text = requirement.markers
     else:
         markers_text = requirement.line
+    return markers_text
 
-    if markers_text is None:
+def matches_python_version(requirement):
+    """Filter out requirements that should not be installed
+    in this Python version.
+    See: https://www.python.org/dev/peps/pep-0508/#environment-markers
+    """
+    python_version_re = re.compile(PYTHON_MARKER_REGEX)
+    markers_text = get_markers_text(requirement)
+    if not markers_text:
         return True
-
-    if 'python_version' not in markers_text:
+    if not 'python_version' in markers_text:
         return True
-
-    match = python_version_re.findall(markers_text)
-    if len(match) > 0:
-        parsed_operator = match[0][0]
-        parsed_python_version = match[0][1]
-
-        if parsed_operator and parsed_python_version:
-            return satisfies_python_requirement(parsed_operator, parsed_python_version)
-        else:
-            return True
+    match = python_version_re.match(markers_text)
+    if not match:
+        return False
+    parsed_operator = match.group('operator')
+    parsed_python_version = match.group('python_version')
+
+    if not parsed_python_version or not parsed_operator:
+        return False
+
+    return satisfies_python_requirement(
+        parsed_operator,
+        parsed_python_version
+    )
 
 
 def matches_environment(requirement):
@@ -148,12 +151,10 @@ def matches_environment(requirement):
     This should be expanded to include other environment markers.
     See: https://www.python.org/dev/peps/pep-0508/#environment-markers
     """
-    # TODO: refactor this out into the Requirement classes
-    if isinstance(requirement, pipfile.PipfileRequirement):
-        markers_text = requirement.markers
-    else:
-        markers_text = requirement.line
-    if markers_text is not None and 'sys_platform' in markers_text:
+    sys_platform_re = re.compile(SYSTEM_MARKER_REGEX)
+    sys_platform = sys.platform.lower()
+    markers_text = get_markers_text(requirement)
+    if markers_text and 'sys_platform' in markers_text:
         match = sys_platform_re.findall(markers_text)
         if len(match) > 0:
             return match[0].lower() == sys_platform

test/inspect.test.js

@@ -373,11 +373,7 @@ test('package installed conditionally based on python version', function (t) {
 test('Pipfile package found conditionally based on python version', function (t) {
   return Promise.resolve().then(function () {
     chdirWorkspaces('pipfile-markers');
-    var venvCreated = testUtils.ensureVirtualenv('pipfile-markers');
-    t.teardown(testUtils.activateVirtualenv('pipfile-markers'));
-    if (venvCreated) {
-      testUtils.pipInstall();
-    }
+    t.teardown(testUtils.activateVirtualenv('pip-app'));
   })
     .then(function () {
       return plugin.inspect('.', 'Pipfile');