booleans 3: values of True and False

I added a new if statement to the numbers_only function in the calculator program because when I tested it with different data types, True and False passed the condition, and made the test fail.

This means that they are also integers or floats even though they are booleans. I want to find out if booleans are integers or floats

open the project

  • I change directory to the booleans folder

    cd booleans

    the terminal shows I am in the booleans folder

    .../pumping_python/booleans

  • I use pytest-watcher to run the tests

    uv run pytest-watcher . --now

    the terminal shows

    rootdir: .../pumping_python/booleans
configfile: pyproject.toml
collected 2 items

tests/test_booleans.py ..                                     [100%]

======================== 2 passed in X.YZs =========================

  • I hold ctrl on the keyboard, then click on tests/test_booleans.py to open it in the editor

is False an integer or a float?

RED: make it fail

I add a new assertion to test_what_is_false

6    def test_what_is_false(self):
7        self.assertIsInstance(False, bool)
8        self.assertNotIsInstance(False, int)
9        self.assertFalse(False)

the terminal shows AssertionError

AssertionError: False is an instance of <class 'int'>

in Python, False is a boolean and an integer

GREEN: make it pass

I change assertNotIsInstance to assertIsInstance

8        self.assertIsInstance(False, int)

the test passes

REFACTOR: make it better

  • I add a comment

    67# False is False
68# False is not true
69# False is a boolean
70# False is an integer
71
72
73# Exceptions Encountered
74# AssertionError

  • I add another assertion to see if False is a float

     6    def test_what_is_false(self):
 7        self.assertIsInstance(False, bool)
 8        self.assertIsInstance(False, int)
 9        self.assertIsInstance(False, float)
10        self.assertFalse(False)

    the terminal shows AssertionError

    AssertionError: False is not an instance of <class 'float'>

    False is not a float

  • I change assertIsInstance to assertNotIsInstance

     8        self.assertIsInstance(False, int)
 9        self.assertNotIsInstance(False, float)
10        self.assertFalse(False)

    the test passes

  • I add a comment

    70# False is a boolean
71# False is an integer
72# False is not a float
73
74
75# Exceptions Encountered
76# AssertionError

  • I can use an iterable with the assertIsInstance method, the same way I do with the isinstance function in the numbers_only function in the calculator

     6    def test_what_is_false(self):
 7        self.assertIsInstance(False, bool)
 8        self.assertIsInstance(False, int)
 9        self.assertNotIsInstance(False, (bool, int))
10        self.assertNotIsInstance(False, float)

    the terminal shows AssertionError

    AssertionError: False is an instance of (<class 'bool'>, <class 'int'>)

  • I change the assertion

    9        self.assertIsInstance(False, (bool, int))

    the test passes

  • I remove the first two assertions in the test since they are covered by the new one

    6    def test_what_is_false(self):
7        self.assertIsInstance(False, (bool, int))
8        self.assertNotIsInstance(False, float)
9        self.assertFalse(False)

  • I use a for loop for the assertions that test_what_is_false

     6    def test_what_is_false(self):
 7        self.assertIsInstance(False, (bool, int))
 8        self.assertNotIsInstance(False, float)
 9        # self.assertFalse(False)
10        # self.assertFalse(None)
11        # self.assertFalse(bool(None))
12        # self.assertFalse(0)
13        # self.assertFalse(bool(0))
14        # self.assertFalse(0.0)
15        # self.assertFalse(bool(0.0))
16        # self.assertFalse(str())
17        # self.assertFalse(bool(str()))
18        # self.assertFalse(tuple())
19        # self.assertFalse(bool(tuple()))
20        # self.assertFalse(list())
21        # self.assertFalse(bool(list()))
22        # self.assertFalse(set())
23        # self.assertFalse(bool(set()))
24        # self.assertFalse(dict())
25        # self.assertFalse(bool(dict()))
26        for false_item in (
27            False,
28            None, bool(None),
29            0, 0.0, bool(0), bool(0.0),
30            str(), bool(str()),
31            tuple(), bool(tuple()),
32            list(), bool(list()),
33            set(), bool(set()),
34            dict(), bool(dict()),
35        ):
36            with self.subTest(item=false_item):
37                self.assertTrue(false_item)
38
39    def test_what_is_true(self):

    the terminal shows AssertionError for all of them

    SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item=None) ...  - AssertionError: None is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item=0) ...     - AssertionError: 0 is not true
SUBFAILED(item=0.0) ...   - AssertionError: 0.0 is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item='') ...    - AssertionError: '' is not true
SUBFAILED(item=False)...  - AssertionError: False is not true
SUBFAILED(item=()) ...    - AssertionError: () is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item=[]) ...    - AssertionError: [] is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item=set()) ... - AssertionError: set() is not true
SUBFAILED(item=False) ... - AssertionError: False is not true
SUBFAILED(item={}) ...    - AssertionError: {} is not true
SUBFAILED(item=False) ... - AssertionError: False is not true

  • I change the assertion

    37                self.assertFalse(false_item)

    the test is green again

  • I remove the commented lines

     6    def test_what_is_false(self):
 7        self.assertIsInstance(False, (bool, int))
 8        self.assertNotIsInstance(False, float)
 9        for false_item in (
10            False,
11            None, bool(None),
12            0, 0.0, bool(0), bool(0.0),
13            str(), bool(str()),
14            tuple(), bool(tuple()),
15            list(), bool(list()),
16            set(), bool(set()),
17            dict(), bool(dict()),
18        ):
19            with self.subTest(item=false_item):
20                self.assertFalse(false_item)
21
22    def test_what_is_true(self):

is True an integer or a float?

RED: make it fail

I add an assertion to test_what_is_true to test if True is also an integer

22    def test_what_is_true(self):
23        self.assertIsInstance(True, bool)
24        self.assertNotIsInstance(True, int)
25        self.assertTrue(True)

the terminal shows AssertionError

AssertionError: True is an instance of <class 'int'>

in Python, True is a boolean and an integer

GREEN: make it pass

I change assertNotIsInstance to assertIsInstance

24        self.assertIsInstance(True, int)

the test passes

REFACTOR: make it better

  • I add a comment

    55# True is a boolean
56# True is an integer
57# the empty dictionary is False
58# the empty set is False

  • I add another assertion to test if True is a float

    22    def test_what_is_true(self):
23        self.assertIsInstance(True, bool)
24        self.assertIsInstance(True, int)
25        self.assertIsInstance(True, float)
26        self.assertTrue(True)

    the terminal shows AssertionError

    AssertionError: True is not an instance of <class 'float'>

    True is not a float

  • I change the assert method

    25        self.assertNotIsInstance(True, float)

    the test passes. This is why my test with different data types failed. True and False are integers and the if statement in the numbers_only function allows integers and floats

  • I add a comment

    55# True is a boolean
56# True is an integer
57# True is not a float
58# the empty dictionary is False

  • I can use an iterable with the assertIsInstance method, the same way I do with the isinstance function in the numbers_only function in the calculator

    22    def test_what_is_true(self):
23        self.assertIsInstance(True, bool)
24        self.assertIsInstance(True, int)
25        self.assertNotIsInstance(True, (bool, int))
26        self.assertNotIsInstance(True, float)

    the terminal shows AssertionError

    AssertionError: True is an instance of (<class 'bool'>, <class 'int'>)

  • I change the assertion

    25        self.assertIsInstance(True, (bool, int))

    the test passes

  • I remove the first two assertions in the test since they are covered by the new one

    22    def test_what_is_true(self):
23        self.assertIsInstance(True, (bool, int))
24        self.assertNotIsInstance(True, float)
25        self.assertTrue(True)

  • I use a for loop for the assertions that test_what_is_true

    22    def test_what_is_true(self):
23        self.assertIsInstance(True, (bool, int))
24        self.assertNotIsInstance(True, float)
25        # self.assertTrue(True)
26        # self.assertTrue(-1)
27        # self.assertTrue(bool(-1))
28        # self.assertTrue(1)
29        # self.assertTrue(bool(1))
30        # self.assertTrue(-0.1)
31        # self.assertTrue(bool(-0.1))
32        # self.assertTrue(0.1)
33        # self.assertTrue(bool(0.1))
34        # self.assertTrue("text")
35        # self.assertTrue(bool("text"))
36        # self.assertTrue((1, 2, 3, 'n'))
37        # self.assertTrue(bool((1, 2, 3, 'n')))
38        # self.assertTrue([1, 2, 3, 'n'])
39        # self.assertTrue(bool([1, 2, 3, 'n']))
40        # self.assertTrue({1, 2, 3, 'n'})
41        # self.assertTrue(bool({1, 2, 3, 'n'}))
42        # self.assertTrue({'key': 'value'})
43        # self.assertTrue(bool({'key': 'value'}))
44        for true_item in (
45            True,
46            -1, bool(-1), 1, bool(1),
47            -0.1, bool(-0.1), 0.1, bool(0.1),
48            "text", bool("text"),
49            ((1, 2, 3, 'n')), bool((1, 2, 3, 'n')),
50            [1, 2, 3, 'n'], bool([1, 2, 3, 'n']),
51            {1, 2, 3, 'n'}, bool({1, 2, 3, 'n'}),
52            {'key': 'value'}, bool({'key': 'value'}),
53        ):
54            with self.subTest(item=true_item):
55                self.assertFalse(true_item)

    the terminal shows AssertionError for all of them

    SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=-1) ...               - AssertionError: -1 is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=1) ...                - AssertionError: 1 is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=-0.1) ...             - AssertionError: -0.1 is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=0.1) ...              - AssertionError: 0.1 is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item='text') ...           - AssertionError: 'text' is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=(1, 2, 3, 'n')) ...   - AssertionError: (1, 2, 3, 'n') is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item=[1, 2, 3, 'n']) ...   - AssertionError: [1, 2, 3, 'n'] is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item={1, 2, 3, 'n'}) ...   - AssertionError: {1, 2, 3, 'n'} is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false
SUBFAILED(item={'key': 'value'}) ... - AssertionError: {'key': 'value'} is not false
SUBFAILED(item=True) ...             - AssertionError: True is not false

  • I change the assertion

    55                self.assertTrue(true_item)

    the test is green again

  • I remove the commented lines

    22    def test_what_is_true(self):
23        self.assertIsInstance(True, (bool, int))
24        self.assertNotIsInstance(True, float)
25
26        for true_item in (
27            True,
28            -1, bool(-1), 1, bool(1),
29            -0.1, bool(-0.1), 0.1, bool(0.1),
30            "text", bool("text"),
31            ((1, 2, 3, 'n')), bool((1, 2, 3, 'n')),
32            [1, 2, 3, 'n'], bool([1, 2, 3, 'n']),
33            {1, 2, 3, 'n'}, bool({1, 2, 3, 'n'}),
34            {'key': 'value'}, bool({'key': 'value'}),
35        ):
36            with self.subTest(item=true_item):
37                self.assertTrue(true_item)
38
39
40# NOTES

test_the_value_of_false

The add function returned numbers in the calculation with True and False because they are integers. I want to know what their values are

RED: make it fail

I add a new test to find out the value of False

36            with self.subTest(item=true_item):
37                self.assertTrue(true_item)
38
39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, None)
41
42
43# NOTES

the terminal shows AssertionError

AssertionError: 1 != None

False is 0

GREEN: make it pass

I change the expectation to match

40          self.assertEqual(False+1, 1)

the test passes

REFACTOR: make it better

  • I add another assertion

    39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, 1)
41        self.assertEqual(False-1, 1)

    the terminal shows AssertionError

    AssertionError: -1 != 1

    False is 0

  • I change the expectation

    41        self.assertEqual(False-1, -1)

    the test passes

  • I add another assertion

    39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, 1)
41        self.assertEqual(False-1, -1)
42        self.assertEqual(False*1, -1)

    the terminal shows AssertionError

    AssertionError: 0 != -1

    False is 0

  • I change the expectation

    38        self.assertEqual(False*1, 0)

    the test passes

  • what happens if I divide a number by False?

    39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, 1)
41        self.assertEqual(False-1, -1)
42        self.assertEqual(False*1, 0)
43        1 / False

    the terminal shows ZeroDivisionError because False is 0

  • I add assertRaises

    39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, 1)
41        self.assertEqual(False-1, -1)
42        self.assertEqual(False*1, 0)
43        with self.assertRaises(ZeroDivisionError):
44            1 / False
45
46
47# NOTES

    the test passes

  • I add a comment

    64# 0 is False
65# None is False
66# False is False
67# False is not true
68# False is a boolean
69# False is an integer
70# False is not a float
71# False is 0

False is 0 in Python

test_the_value_of_true

RED: make it fail

I add a new test to find out the value of True

39    def test_the_value_of_false(self):
40        self.assertEqual(False+1, 1)
41        self.assertEqual(False-1, -1)
42        self.assertEqual(False*1, 0)
43        with self.assertRaises(ZeroDivisionError):
44            1 / False
45
46    def test_the_value_of_true(self):
47        self.assertEqual(True+1, 1)
48
49
50# NOTES

the terminal shows AssertionError

AssertionError: 2 != 1

True is 1

GREEN: make it pass

I change the expectation

47        self.assertEqual(True+1, 2)

the test passes

REFACTOR: make it better

  • I add another assertion

    46    def test_the_value_of_true(self):
47        self.assertEqual(True+1, 2)
48        self.assertEqual(True-1, 2)

    the terminal shows AssertionError

    AssertionError: 0 != 2

    True is 1

  • I change the expectation

    48        self.assertEqual(True-1, 0)

    the test passes

  • I add an assertion

    46    def test_the_value_of_true(self):
47        self.assertEqual(True+1, 2)
48        self.assertEqual(True-1, 0)
49        self.assertEqual(True*1, 0)

    the terminal shows AssertionError

    AssertionError: 1 != 0

    True is 1

  • I change the expectation

    49        self.assertEqual(True*1, 1)

    the test passes

  • I add an assertion for division

    46    def test_the_value_of_true(self):
47        self.assertEqual(True+1, 2)
48        self.assertEqual(True-1, 0)
49        self.assertEqual(True*1, 1)
50        self.assertEqual(True/2, 1)

    the terminal shows AssertionError

    AssertionError: 0.5 != 1

    True is 1

  • I change the assertion

    46    def test_the_value_of_true(self):
47        self.assertEqual(True+1, 2)
48        self.assertEqual(True-1, 0)
49        self.assertEqual(True*1, 1)
50        self.assertEqual(True/1, 1)
51
52
53# NOTES

    the test passes

  • I add a comment

    53# NOTES
54# a dictionary with things is True
55# a set with things is True
56# a list with things is True
57# a tuple with things is True
58# a string with things is True
59# positive and negative numbers are True
60# True is True
61# True is not false
62# True is a boolean
63# True is an integer
64# True is not a float
65# True is 1
66# the empty dictionary is False
67# the empty set is False
68# the empty list is False
69# the empty tuple is False
70# the empty string is False
71# 0 is False
72# None is False
73# False is False
74# False is not true
75# False is a boolean
76# False is an integer
77# False is not a float
78# False is 0
79
80
81# Exceptions seen
82# AssertionError

close the project

  • I close test_booleans.py in the editor

  • I click in the terminal, then use q on the keyboard to leave the tests. The terminal goes back to the command line

  • I change directory to the parent of booleans

    cd ..

    the terminal shows

    .../pumping_python

    I am back in the pumping_python directory

review

I added assertions that show booleans are also integers and NOT floats, then I added these tests

code from the chapter

Do you want to see all the CODE I typed in this chapter?

what is next?

you know

Would you like to test dictionaries?

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