Factor path inspection into separate function.

Author: chrahunt

src/pip/_internal/req/constructors.py

@@ -82,6 +82,15 @@ def convert_extras(extras):
         return set()
 
 
+def looks_like_path(text):
+    # type: (str) -> bool
+    return (
+        os.path.sep in text or
+        os.path.altsep is not None and os.path.altsep in text or
+        text.startswith('.')
+    )
+
+
 def parse_editable(editable_req):
     # type: (str) -> Tuple[Optional[str], str, Optional[Set[str]]]
     """Parses an editable requirement into:
@@ -263,11 +272,7 @@ def install_req_from_line(
         link = Link(name)
     else:
         p, extras_as_string = _strip_extras(path)
-        looks_like_dir = os.path.isdir(p) and (
-            os.path.sep in name or
-            (os.path.altsep is not None and os.path.altsep in name) or
-            name.startswith('.')
-        )
+        looks_like_dir = os.path.isdir(p) and looks_like_path(name)
         if looks_like_dir:
             if not is_installable_dir(p):
                 raise InstallationError(