Adds tests, linting.

tasks.py

@@ -19,12 +19,17 @@ def strtobool(val: str) -> bool:
         bool: True or False
     """
     val = val.lower()
+
+    # Check for valid truth values
     if val in ("y", "yes", "t", "true", "on", "1"):
         return True
-    elif val in ("n", "no", "f", "false", "off", "0"):
+
+    # Check for valid false values
+    if val in ("n", "no", "f", "false", "off", "0"):
         return False
-    else:
-        raise ValueError("invalid truth value %r" % (val,))
+
+    # Raise error if not valid truth value
+    raise ValueError("invalid truth value %r" % (val,))
 
 
 def is_truthy(arg):

tests/test_tasks.py

@@ -0,0 +1,31 @@
+"""Test functions for tasks.py."""
+import pytest
+
+from tasks import strtobool
+
+@pytest.mark.parametrize(
+    "test_case, expected",
+    [
+        ("y", True),
+        ("yes", True),
+        ("true", True),
+        ("t", True),
+        ("on", True),
+        ("1", True),
+        ("n", False),
+        ("no", False),
+        ("false", False),
+        ("f", False),
+        ("off", False),
+        ("0", False),
+    ],
+)
+def test_strtobool(test_case, expected):
+    """Test strtobool function."""
+    assert strtobool(test_case) == expected
+
+def test_strtobool_error():
+    """Test generation of the error message."""
+    with pytest.raises(ValueError) as excinfo:
+        strtobool("invalid")
+    assert "Invalid truth value invalid" in str(excinfo.value)