converted _parse_raw_version_string to a staticmethod

Author: dantownsend

piccolo/engine/postgres.py

@@ -227,7 +227,8 @@ def __init__(self, config: t.Dict[str, t.Any]) -> None:
         )
         super().__init__()
 
-    def _parse_raw_version_string(self, version_string: str) -> float:
+    @staticmethod
+    def _parse_raw_version_string(version_string: str) -> float:
         """
         The format of the version string isn't always consistent. Sometimes
         it's just the version number e.g. '9.6.18', and sometimes

tests/engine/test_version_parsing.py

@@ -11,18 +11,17 @@ def test_version_parsing(self):
         Make sure the version number can correctly be parsed from a range
         of known formats.
         """
-        engine = PostgresEngine(config={})
-
         self.assertEqual(
-            engine._parse_raw_version_string(version_string="9.4"), 9.4
+            PostgresEngine._parse_raw_version_string(version_string="9.4"), 9.4
         )
 
         self.assertEqual(
-            engine._parse_raw_version_string(version_string="9.4.1"), 9.4
+            PostgresEngine._parse_raw_version_string(version_string="9.4.1"),
+            9.4,
         )
 
         self.assertEqual(
-            engine._parse_raw_version_string(
+            PostgresEngine._parse_raw_version_string(
                 version_string="12.4 (Ubuntu 12.4-0ubuntu0.20.04.1)"
             ),
             12.4,