Fix is_env_truthy

docs/advanced.rst

@@ -636,7 +636,7 @@ truthy value (i.e. ``"1"``)::
 
     $ PIPENV_IGNORE_VIRTUALENVS=1
 
-To explicitly disable a boolean option, assign to it a falsy value (i.e. ``"0"``).
+To explicitly disable a boolean option, assign to it a falsey value (i.e. ``"0"``).
 
 .. autoclass:: pipenv.environments.Setting
     :members:

pipenv/utils/shell.py

@@ -395,21 +395,28 @@ def env_to_bool(val):
     Convert **val** to boolean, returning True if truthy or False if falsey
 
     :param Any val: The value to convert
-    :return: False if Falsey, True if truthy
+    :return: False if falsey, True if truthy
     :rtype: bool
+    :raises:
+        ValueError: if val is not a valid boolean-like
     """
     if isinstance(val, bool):
         return val
-    if val.lower() in FALSE_VALUES:
-        return False
-    if val.lower() in TRUE_VALUES:
-        return True
+
+    try:
+        if val.lower() in FALSE_VALUES:
+            return False
+        if val.lower() in TRUE_VALUES:
+            return True
+    except AttributeError:
+        pass
+
     raise ValueError(f"Value is not a valid boolean-like: {val}")
 
 
 def is_env_truthy(name):
     """An environment variable is truthy if it exists and isn't one of (0, false, no, off)"""
-    return env_to_bool(os.getenv(name))
+    return env_to_bool(os.getenv(name, False))
 
 
 def project_python(project, system=False):

tests/unit/test_utils.py

@@ -3,7 +3,6 @@ from unittest import mock
 
 import pytest
 
-import pipenv.utils.shell
 from pipenv.utils import dependencies
 from pipenv.utils import indexes
 from pipenv.utils import internet
@@ -338,7 +337,7 @@ twine = "*"
     )
     @pytest.mark.skipif(os.name != "nt", reason="Windows file paths tested")
     def test_win_normalize_drive(self, input_path, expected):
-        assert pipenv.utils.shell.normalize_drive(input_path) == expected
+        assert shell.normalize_drive(input_path) == expected
 
     @pytest.mark.utils
     @pytest.mark.parametrize(
@@ -352,7 +351,7 @@ twine = "*"
     )
     @pytest.mark.skipif(os.name == "nt", reason="*nix file paths tested")
     def test_nix_normalize_drive(self, input_path, expected):
-        assert pipenv.utils.shell.normalize_drive(input_path) == expected
+        assert shell.normalize_drive(input_path) == expected
 
     @pytest.mark.utils
     @pytest.mark.parametrize(
@@ -490,3 +489,37 @@ twine = "*"
             python = shell.project_python(project, system=True)
 
         assert python == "/usr/local/bin/python3"
+
+    @pytest.mark.utils
+    @pytest.mark.parametrize(
+        "val, expected",
+        (
+            (True, True),
+            (False, False),
+            ("true", True),
+            ("1", True),
+            ("off", False),
+            ("0", False),
+        )
+    )
+    def test_env_to_bool(self, val, expected):
+        actual = shell.env_to_bool(val)
+        assert actual == expected
+
+    @pytest.mark.utils
+    def test_is_env_truthy_exists_true(self, monkeypatch):
+        name = "ZZZ"
+        monkeypatch.setenv(name, "1")
+        assert shell.is_env_truthy(name) is True
+
+    @pytest.mark.utils
+    def test_is_env_truthy_exists_false(self, monkeypatch):
+        name = "ZZZ"
+        monkeypatch.setenv(name, "0")
+        assert shell.is_env_truthy(name) is False
+
+    @pytest.mark.utils
+    def test_is_env_truthy_does_not_exisxt(self, monkeypatch):
+        name = "ZZZ"
+        monkeypatch.delenv(name, raising=False)
+        assert shell.is_env_truthy(name) is False