Make strtobool() return a boolean value, not an integer (0, 1) (#1565)

config/settings/dev.py

@@ -70,7 +70,7 @@
         "debug_toolbar.middleware.DebugToolbarMiddleware",
     ]
 
-    def show_toolbar(request):
+    def show_toolbar(request) -> bool:
         return strtobool(os.getenv("DEBUG_TOOLBAR", "False"))
 
     DEBUG_TOOLBAR_CONFIG = {

config/settings/util.py

@@ -1,13 +1,13 @@
-def strtobool(val):
-    """Convert a string representation of truth to true (1) or false (0).
+def strtobool(val: str) -> bool:
+    """Convert a string representation of truth to true or false.
     True values are 'y', 'yes', 't', 'true', 'on', and '1'; false values
     are 'n', 'no', 'f', 'false', 'off', and '0'.  Raises ValueError if
     'val' is anything else.
     """
     val = val.lower()
     if val in ("y", "yes", "t", "true", "on", "1"):
-        return 1
+        return True
     elif val in ("n", "no", "f", "false", "off", "0"):
-        return 0
+        return False
     else:
         raise ValueError("invalid truth value %r" % (val,))

etna/tests/test_config.py

@@ -0,0 +1,78 @@
+# This file lives here rather than in the config package, because the test runner
+# does not seem able to find it there. Also the test.py setting file is being
+# discovered as a test.
+import django.test
+
+from config.settings.util import strtobool
+
+
+class TestStrToBool(django.test.SimpleTestCase):
+    TRUTHY_VALUES = (
+        "y",
+        "yes",
+        "t",
+        "true",
+        "on",
+        "1",
+        "Y",
+        "YES",
+        "T",
+        "TRUE",
+        "ON",
+        "oN",
+        "tRuE",
+        "YeS",
+        "Yes",
+    )
+
+    def test_truthy_values(self) -> None:
+        for value in self.TRUTHY_VALUES:
+            with self.subTest(value=value):
+                self.assertIs(strtobool(value), True)
+
+    FALSY_VALUES = (
+        "n",
+        "no",
+        "f",
+        "false",
+        "off",
+        "0",
+        "N",
+        "NO",
+        "F",
+        "FALSE",
+        "OFF",
+        "fALsE",
+        "nO",
+        "No",
+        "ofF",
+    )
+
+    def test_falsy_values(self) -> None:
+        for value in self.FALSY_VALUES:
+            with self.subTest(value=value):
+                self.assertIs(strtobool(value), False)
+
+    INCORRECT_VALUES = (
+        "",
+        " ",
+        "\t",
+        " n",
+        " no ",
+        " f ",
+        " false ",
+        " off ",
+        "random value",
+    )
+
+    def test_incorrect_values(self):
+        for value in self.INCORRECT_VALUES:
+            exception_message = f"invalid truth value {value!r}"
+            with self.subTest(value=value, exception_message=exception_message):
+                with self.assertRaises(ValueError) as cm:
+                    strtobool(value)
+                # We are using assertRaises instead of assertRaisesRegex
+                # because we want to test values like "\t" which won't work
+                # with assertRaisesRegex. Therefore we need to test the message
+                # with assertEqual separately.
+                self.assertEqual(str(cm.exception), exception_message)