telephone

Part of Computer Programming is sending input data to a process and getting output data back

input_object -> process -> output_object

I send things (input data) to a program to test it, and check if what I think will happen (my expectation) is the same as the results I get (reality). This helps me answer two questions:

  • what is the same?

  • what is different?

The difference helps me know what to change to get what I want. I use assertions to test if reality is the same as my expectation.

assert reality == my_expectation

where

  • reality is what happens when I do something with code

  • my expectation is what I think will happen when I do something with code

The exercises in this chapter show how I can pass objects to a function and use it to make a string (anything in quotes).

preview

I have these tests by the end of the chapter

telephone/tests/test_telephone.py
 1def assert_equal(a, b):
 2    assert a == b
 3
 4
 5def text(the_input):
 6    return f'I got: {the_input}'
 7
 8
 9def test_passing_none():
10    assert_equal(text(None), 'I got: None')
telephone/tests/test_telephone.py
13def test_passing_booleans():
14    assert_equal(text(False), 'I got: False')
15    assert_equal(text(True), 'I got: True')
16
17
18def test_passing_an_integer():
19    an_integer = 1234
20    assert_equal(text(an_integer), f'I got: {an_integer}')
21
22
23def test_passing_a_float():
24    a_float = 5.678
25    assert_equal(text(a_float), f'I got: {a_float}')
telephone/tests/test_telephone.py
28def test_passing_a_string():
29    a_string = 'hello'
30    assert_equal(text(a_string), f'I got: {a_string}')
31
32
33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(text(a_tuple), f"I got: {a_tuple}")
36
37
38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(text(a_list), f'I got: {a_list}')
telephone/tests/test_telephone.py
43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(text(a_set), f'I got: {a_set}')
46
47
48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    reality = text(a_dictionary)
54    my_expectation = f'I got: {a_dictionary}'
55    assert_equal(reality, my_expectation)
telephone/tests/test_telephone.py
58def test_passing_a_class():
59    assert_equal(
60        text(object), "I got: <class 'object'>"
61    )
62    assert_equal(text(bool), "I got: <class 'bool'>")
63    assert_equal(text(int), "I got: <class 'int'>")
64    assert_equal(text(float), "I got: <class 'float'>")
65    assert_equal(text(str), "I got: <class 'str'>")
66    assert_equal(text(tuple), "I got: <class 'tuple'>")
67    assert_equal(text(list), "I got: <class 'list'>")
68    assert_equal(text(set), "I got: <class 'set'>")
69    assert_equal(text(dict), "I got: <class 'dict'>")
70
71
72# Exceptions seen
73# AssertionError
74# NameError
75# TypeError

start the project

  • I name this project telephone

  • I open a terminal

  • I use uv to make a directory for the project and initialize it

    uv init telephone

    the terminal shows

    Initialized project `telephone`
at `.../pumping_python/telephone`

    then goes back to the command line.

  • I change directory to the project

    cd telephone

    the terminal shows I am in the telephone folder

    .../pumping_python/telephone

  • I make a directory for the tests

    mkdir tests

    the terminal goes back to the command line.

  • I make the tests directory a Python package

    Danger

    use 2 underscores (__) before and after init for __init__.py not _init_.py

    touch tests/__init__.py

    New-Item tests/__init__.py

    the terminal goes back to the command line.

  • I make an empty file for the tests in the tests folder

    touch tests/test_telephone.py

    New-Item tests/test_telephone.py

    the terminal goes back to the command line.

  • I open test_telephone.py from the tests folder

  • I add the first failing test to test_telephone.py

    1def test_failure():
2    assert False is True

  • I go back to the terminal

  • I use echo to add pytest to requirements.txt

    echo "pytest" > requirements.txt

  • I add pytest-watcher to the requirements file

    echo "pytest-watcher" >> requirements.txt

    the terminal goes back to the command line.

  • I use Out-File to add pytest to requirements.txt

    "pytest" | Out-File requirements.txt -Encoding UTF8

  • I add pytest-watcher to the requirements file

    "pytest-watcher" >> requirements.txt

  • I use uv to install pytest-watcher with the requirements file

    uv add --requirement requirements.txt

    the terminal shows that it installed pytest-watcher and its dependencies.

  • I add the new files and folders to git for tracking

    git add .

    the terminal goes back to the command line.

  • I add a git commit message

    git commit --all --message 'setup project'

    the terminal shows a summary of the changes then goes back to the command line.

  • I use pytest-watcher to run the tests automatically

    uv run pytest-watcher . --now

    the terminal is my friend, and shows AssertionError

    ======================== FAILURES ========================
______________________ test_failure ______________________

    def test_failure():
>       assert False is True
E       assert False is True

test_telephone.py:2: AssertionError
================ short test summary info =================
FAILED test_telephone.py::test_failure - assert False is True
=================== 1 failed in X.YZs ====================

    because False is NOT True.

    if the terminal does not show the same error, then check if

    • your tests/__init__.py has two underscores (__) before and after init for __init__.py not _init_.py

    • you ran echo "pytest-watcher" >> requirements.txt, to add pytest-watcher to the requirements file

    and try uv run pytest-watcher . --now again

  • I add AssertionError to the list of Exceptions seen, to test_telephone.py

    1def test_failure():
2    assert False is True
3
4
5# Exceptions seen
6# AssertionError

  • I change True to False in the assertion

    1def test_failure():
2    # assert False is True
3    assert False is False
4
5
6# Exceptions seen
7# AssertionError

    the test passes.

test_passing_none

Can I pass None (the simplest object) as input to a function?

RED: make it fail

GREEN: make it pass

  • I add the function

    1def test_passing_none():
2    def text():
3        return None
4
5    assert text(None) == 'I got: None'
6
7
8# Exceptions seen

    the terminal is my friend, and shows TypeError

    TypeError: test_passing_none.<locals>.text()
           takes 0 positional arguments but 1 was given

    because the assertion called the text function which belongs to test_passing_none with input (None) and the function definition does not allow any inputs, the parentheses are empty.

  • I add TypeError to the list of Exceptions seen

     8# Exceptions seen
 9# AssertionError
10# NameError
11# TypeError

  • I add a name to the function definition

    1def test_passing_none():
2    # def text():
3    def text(the_input):
4        return None
5
6    assert text(None) == 'I got: None'
7
8
9# Exceptions seen

    • the_input is the name I used for the input, I can use any name I want.

    • the terminal is my friend, and shows AssertionError

      E       assert None == 'I got: None'

    because the assertion expects 'I got: None' and the text function returns None.

  • I copy the string from the terminal and paste it in the return statement to replace None

     1def test_passing_none():
 2    # def text():
 3    def text(the_input):
 4        # return None
 5        return 'I got: None'
 6
 7    assert text(None) == 'I got: None'
 8
 9
10# Exceptions seen

    the test passes.

    text(None) -> 'I got: None'
└── def text(the_input):
    └── return 'I got: None'

REFACTOR: make it better

  • I remove the commented lines from test_passing_none

    1def test_passing_none():
2    def text(the_input):
3        return 'I got: None'
4
5    assert text(None) == 'I got: None'
6
7
8# Exceptions seen

  • I open a new terminal then change directories to telephone

    cd telephone

    the terminal shows I am in the telephone folder

    .../pumping_python/telephone

  • I add a git commit message in the new terminal

    git commit -am 'add test_passing_none'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass None as input to a function.

The problem with this solution is that the text function does not care about what it gets, it always returns 'I got: None' when it is called. I want it to return the object it gets as part of the string.

test_passing_booleans

Can I pass booleans from a test to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for booleans (there are only two), first with an assertion for False, to test_telephone.py

     1def test_passing_none():
 2    def text(the_input):
 3        return 'I got: None'
 4
 5    assert text(None) == 'I got: None'
 6
 7
 8def test_passing_booleans():
 9    assert text(False) == 'I got: False'
10
11
12# Exceptions seen

    the terminal is my friend, and shows NameError

    NameError: name 'text' is not defined

    because the text function belongs to the test_passing_none function and I cannot reach it from outside.

GREEN: make it pass

  • I move the text function out of test_passing_none so that it can be called from anywhere in the file

    1def text(the_input):
2    return 'I got: None'
3
4
5def test_passing_none():
6    assert text(None) == 'I got: None'
7
8
9def test_passing_booleans():

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: None'
                    == 'I got: False'

    because the text function always returns 'I got: None' and this assertion expects 'I got: False'.

  • I change the return statement to give the test what it wants

    1def text(the_input):
2    # return 'I got: None'
3    return 'I got: False'
4
5
6def test_passing_none():

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: False' == 'I got: None'

what is string interpolation?

String Interpolation is how to place objects in strings. It allows me to make one string that can have values that change.

I can use an f-string (short for formatted string literal) for string interpolation.

A string is anything inside quotes, for example

  • 'single quotes'

  • '''triple single quotes'''

  • "double quotes"

  • """triple double quotes"""

how to write an f-string

f'characters {object} more characters'

  • I add the_input to the string in the return statement of the text function

    1def text(the_input):
2    # return 'I got: None'
3    # return 'I got: False'
4    return 'I got: {the_input}'

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: {the_input}'
                    == 'I got: False'

  • I change the return statement to an f-string

    1def text(the_input):
2    # return 'I got: None'
3    # return 'I got: False'
4    # return 'I got: {the_input}'
5    return f'I got: {the_input}'
6
7
8def test_passing_none():

    the test passes because Python uses the string representation of the object in the curly braces { }

    text(None) -> 'I got: None'
└── def text(the_input):
    ├── the_input = None
    └── return f'I got: {the_input}'
        return  'I got:  None      '

    text(False) -> 'I got: False'
└── def text(the_input):
    ├── the_input = False
    └── return f'I got: {the_input}'
        return  'I got:  False     '

REFACTOR: make it better

  • I remove the commented lines from the text function

    1def text(the_input):
2    return f'I got: {the_input}'
3
4
5def test_passing_none():

  • I add an assertion for True (the other boolean) to test_passing_booleans

     9def test_passing_booleans():
10    assert text(False) == 'I got: False'
11    assert text(True) == 'I got: "True"'
12
13
14# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert 'I got: True'
            == 'I got: "True"

  • I remove the quotes around True in my expectation

     9def test_passing_booleans():
10    assert text(False) == 'I got: False'
11    # assert text(True) == 'I got: "True"'
12    assert text(True) == 'I got: True'
13
14
15# Exceptions seen

    the test passes because Python uses the string representation of the object in the curly braces { }

    text(True) -> 'I got: True'
└── def text(the_input):
    ├── the_input = True
    └── return f'I got: {the_input}'
        return  'I got:  True      '

  • I add the assert_equal function

    1def assert_equal(a, b):
2    assert a == b
3
4
5def text(the_input):

  • I use the assert_equal function in test_passing_none

     9def test_passing_none():
10    # assert text(None) == 'I got: None'
11    assert_equal(text(None), 'I got: BOOM!!!')
12
13
14def test_passing_booleans():

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: None' == 'I got: BOOM!!!'

  • I change the expectation of the assertion to match reality

     9def test_passing_none():
10    # assert text(None) == 'I got: None'
11    # assert_equal(text(None), 'I got: BOOM!!!')
12    assert_equal(text(None), 'I got: None')
13
14
15def test_passing_booleans():

    the test passes.

  • I remove the commented lines from test_passing_none

     9def test_passing_none():
10    assert_equal(text(None), 'I got: None')
11
12
13def test_passing_booleans():

  • I use the assert_equal function in test_passing_booleans

    13def test_passing_booleans():
14    # assert text(False) == 'I got: False'
15    # assert text(True) == 'I got: "True"'
16    # assert text(True) == 'I got: True'
17    assert_equal(text(False), 'I got: False')
18    assert_equal(text(True), 'I got: True')
19
20
21# Exceptions seen

    the test is still green.

  • I remove the commented lines from test_passing_booleans

    13def test_passing_booleans():
14    assert_equal(text(False), 'I got: False')
15    assert_equal(text(True), 'I got: True')
16
17
18# Exceptions seen

  • I add a git commit message in the other terminal

    git commit --all --message \
'add test_passing_booleans'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass booleans as input to a function.

test_passing_an_integer

Can I pass an integer (a whole number without decimals) as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for an integer to test_telephone.py

    13def test_passing_booleans():
14    assert_equal(text(False), 'I got: False')
15    assert_equal(text(True), 'I got: True')
16
17
18def test_passing_an_integer():
19    assert_equal(text(1234), 'I got: "1234"')
20
21
22# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert 'I got: 1234'
            == 'I got: "1234"'

GREEN: make it pass

I remove the quotes around the integer in my expectation

18def test_passing_an_integer():
19    # assert_equal(text(1234), 'I got: "1234"')
20    assert_equal(text(1234), 'I got: 1234')
21
22
23# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text(1234) -> 'I got: 1234'
└── def text(the_input):
    ├── the_input = 1234
    └── return f'I got: {the_input}'
        return  'I got:  1234      '

REFACTOR: make it better

  • I add a variable for 1234

    18def test_passing_an_integer():
19    an_integer = 1234
20    # assert_equal(text(1234), 'I got: "1234"')
21    assert_equal(text(1234), 'I got: 1234')
22
23
24# Exceptions seen

  • I use the variable to remove repetition of 1234

    18def test_passing_an_integer():
19    an_integer = 1234
20    # assert_equal(text(1234), 'I got: "1234"')
21    # assert_equal(text(1234), 'I got: 1234')
22    assert_equal(text(an_integer), 'I got: an_integer')
23
24
25# Exceptions seen

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: 1234'
                    == 'I got: an_integer'

  • I change my expectation to an f-string

    18def test_passing_an_integer():
19    an_integer = 1234
20    # assert_equal(text(1234), 'I got: "1234"')
21    # assert_equal(text(1234), 'I got: 1234')
22    # assert_equal(text(an_integer), 'I got: an_integer')
23    assert_equal(text(an_integer), f'I got: {an_integer}')
24
25
26# Exceptions seen

    the test passes

  • I remove the commented lines from test_passing_an_integer

    18def test_passing_an_integer():
19    an_integer = 1234
20    assert_equal(text(an_integer), f'I got: {an_integer}')
21
22
23# Exceptions seen

  • I add a git commit message in the other terminal

    git commit -am 'add test_passing_an_integer'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass an integer as input to a function.

test_passing_a_float

Can I pass a float (binary floating point decimal number) as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a float (binary floating point decimal numbers) to test_telephone.py

    18def test_passing_an_integer():
19    an_integer = 1234
20    assert_equal(text(an_integer), f'I got: {an_integer}')
21
22
23def test_passing_a_float():
24    assert_equal(text(5.678), 'I got: "5.678"')
25
26
27# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert 'I got: 5.678'
            == 'I got: "5.678"'

GREEN: make it pass

I remove the quotes around the float in my expectation

23def test_passing_a_float():
24    # assert_equal(text(5.678), 'I got: "5.678"')
25    assert_equal(text(5.678), 'I got: 5.678')
26
27
28# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text(5.678) -> 'I got: 5.678'
└── def text(the_input):
    ├── the_input = 5.678
    └── return f'I got: {the_input}'
        return  'I got:  5.678     '

REFACTOR: make it better

  • I add a variable for 5.678

    23def test_passing_a_float():
24    a_float = 5.678
25    # assert_equal(text(5.678), 'I got: "5.678"')
26    assert_equal(text(5.678), 'I got: 5.678')
27
28
29# Exceptions seen

  • I use the variable to remove repetition of 5.678

    23def test_passing_a_float():
24    a_float = 5.678
25    # assert_equal(text(5.678), 'I got: "5.678"')
26    # assert_equal(text(5.678), 'I got: 5.678')
27    assert_equal(text(a_float), 'I got: a_float')
28
29
30# Exceptions seen

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: 5.678'
                    == 'I got: a_float'

  • I change my expectation to an f-string

    23def test_passing_a_float():
24    a_float = 5.678
25    # assert_equal(text(5.678), 'I got: "5.678"')
26    # assert_equal(text(5.678), 'I got: 5.678')
27    # assert_equal(text(a_float), 'I got: a_float')
28    assert_equal(text(a_float), f'I got: {a_float}')
29
30
31# Exceptions seen

    the test passes.

  • I remove the commented lines from test_passing_a_float

    23def test_passing_a_float():
24    a_float = 5.678
25    assert_equal(text(a_float), f'I got: {a_float}')
26
27
28# Exceptions seen

  • I add a git commit message in the other terminal

    git commit --all --message \
'add test_passing_a_float'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a float as input to a function.

test_passing_a_string

Can I pass a string as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a string (anything in quotes) to test_telephone.py

    23def test_passing_a_float():
24    a_float = 5.678
25    assert_equal(text(a_float), f'I got: {a_float}')
26
27
28def test_passing_a_string():
29    assert_equal(text('hello'), 'I got: hi')
30
31
32# Exceptions seen

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: hello'
                    == 'I got: hi'

GREEN: make it pass

I change my expectation to match reality

28def test_passing_a_string():
29    # assert_equal(text('hello'), 'I got: hi')
30    assert_equal(text('hello'), 'I got: hello')
31
32
33# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text('hello') -> 'I got: hello'
└── def text(the_input):
    ├── the_input = 'hello'
    └── return f'I got: {the_input}'
        return  'I got:  hello     '

REFACTOR: make it better

  • I add a variable for 'hello'

    28def test_passing_a_string():
29    a_string = 'hello'
30    # assert_equal(text('hello'), 'I got: hi')
31    assert_equal(text('hello'), 'I got: hello')
32
33
34# Exceptions seen

  • I use the variable to remove repetition of 'hello'

    28def test_passing_a_string():
29    a_string = 'hello'
30    # assert_equal(text('hello'), 'I got: hi')
31    # assert_equal(text('hello'), 'I got: hello')
32    assert_equal(text(a_string), 'I got: a_string')
33
34
35# Exceptions seen

    the terminal is my friend, and shows AssertionError

    AssertionError: assert 'I got: hello'
                    == 'I got: a_string'

  • I change my expectation to an f-string

    28def test_passing_a_string():
29    a_string = 'hello'
30    # assert_equal(text('hello'), 'I got: hi')
31    # assert_equal(text('hello'), 'I got: hello')
32    # assert_equal(text(a_string), 'I got: a_string')
33    assert_equal(text(a_string), f'I got: {a_string}')
34
35
36# Exceptions seen

    the test passes.

  • I remove the commented lines from test_passing_a_string

    28def test_passing_a_string():
29    a_string = 'hello'
30    assert_equal(text(a_string), f'I got: {a_string}')
31
32
33# Exceptions seen

  • I add a git commit message in the other terminal

    git commit -am 'add test_passing_a_string'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a string as input to a function.

test_passing_a_tuple

Can I pass a tuple (anything in parentheses ( ) separated by a comma) as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a tuple to test_telephone.py

    28def test_passing_a_string():
29    a_string = 'hello'
30    assert_equal(text('hello'), f'I got: {a_string}')
31
32
33def test_passing_a_tuple():
34    assert_equal(
35        text((0, 1, 2, 'n')),
36        "I got: (0, 1, 2, n)"
37    )
38
39
40# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: (0, 1, 2, 'n')"
            == 'I got: (0, 1, 2, n)'

GREEN: make it pass

I change the tuple in my expectation to match reality

33def test_passing_a_tuple():
34    assert_equal(
35        text((0, 1, 2, 'n')),
36        # "I got: (0, 1, 2, n)"
37        "I got: (0, 1, 2, 'n')"
38    )
39
40
41# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text((0, 1, 2, 'n')) -> "I got: (0, 1, 2, 'n')"
└── def text(the_input):
    ├── the_input = (0, 1, 2, 'n')
    └── return f'I got: {  the_input  }'
        return  "I got:  (0, 1, 2, 'n')"

REFACTOR: make it better

  • I add a variable for (0, 1, 2, 'n')

    33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(
36        text((0, 1, 2, 'n')),
37        # "I got: (0, 1, 2, n)"
38        "I got: (0, 1, 2, 'n')"
39    )
40
41
42# Exceptions seen

  • I use the variable to remove repetition of (0, 1, 2, 'n')

    33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(
36        # text((0, 1, 2, 'n')),
37        # "I got: (0, 1, 2, n)"
38        # "I got: (0, 1, 2, 'n')"
39        text(a_tuple), "I got: a_tuple"
40    )
41
42
43# Exceptions seen

    the terminal is my friend, and shows AssertionError

    assert "I got: (0, 1, 2, 'n')"
    == 'I got: a_tuple'

  • I change my expectation to an f-string

    33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(
36        # text((0, 1, 2, 'n')),
37        # "I got: (0, 1, 2, n)"
38        # "I got: (0, 1, 2, 'n')"
39        # text(a_tuple), "I got: a_tuple"
40        text(a_tuple), f"I got: {a_tuple}"
41    )
42
43
44# Exceptions seen

    the test passes.

  • I remove the commented lines from test_passing_a_tuple

    33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(text(a_tuple), f"I got: {a_tuple}")
36
37
38# Exceptions seen

  • I add a git commit message in the other terminal

    git commit --all --message \
'add test_passing_a_tuple'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a tuple as input to a function.

test_passing_a_list

Can I pass a list (anything in square brackets [ ]) from a test to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a list to test_telephone.py

    33def test_passing_a_tuple():
34    a_tuple = (0, 1, 2, 'n')
35    assert_equal(text(a_tuple), f"I got: {a_tuple}")
36
37
38def test_passing_a_list():
39    assert_equal(
40        text([0, 1, 2, 'n']),
41        'I got: [0, 1, 2, "n"]'
42    )
43
44
45# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: [0, 1, 2, 'n']"
            == 'I got: [0, 1, 2, "n"]'

GREEN: make it pass

I change the list in my expectation to match reality

38def test_passing_a_list():
39    assert_equal(
40        text([0, 1, 2, 'n']),
41        # 'I got: [0, 1, 2, "n"]'
42        "I got: [0, 1, 2, 'n']"
43    )
44
45
46# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text([0, 1, 2, 'n']) -> "I got: [0, 1, 2, 'n']"
└── def text(the_input):
    ├── the_input = [0, 1, 2, 'n']
    └── return f'I got: {  the_input  }'
        return  "I got:  [0, 1, 2, 'n']"

Python changed the double quotes (") in the list to a single quote (').

REFACTOR: make it better

  • I add a variable for [0, 1, 2, 'n']

    38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(
41        text([0, 1, 2, 'n']),
42        # 'I got: [0, 1, 2, "n"]'
43        "I got: [0, 1, 2, 'n']"
44    )
45
46
47# Exceptions seen

  • I use the variable to remove repetition of [0, 1, 2, 'n']

    38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(
41        # text([0, 1, 2, 'n']),
42        # 'I got: [0, 1, 2, "n"]'
43        # "I got: [0, 1, 2, 'n']"
44        text(a_list), 'I got: a_list'
45    )
46
47
48# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: [0, 1, 2, 'n']"
            == 'I got: a_list'

  • I change my expectation to an f-string

    38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(
41        # text([0, 1, 2, 'n']),
42        # 'I got: [0, 1, 2, "n"]'
43        # "I got: [0, 1, 2, 'n']"
44        # text(a_list), 'I got: a_list'
45        text(a_list), f'I got: {a_list}'
46    )
47
48
49# Exceptions seen

    the test is still green.

  • I remove the commented lines from test_passing_a_list

    38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(text(a_list), f'I got: {a_list}')
41
42
43# Exceptions seen

  • I add a git commit message in the other terminal

    git commit -am 'add test_passing_a_list'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a list as input to a function.

test_passing_a_set

Can I pass a set (anything in curly braces { }, not key-value pairs) from a test to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a set to test_telephone.py

    38def test_passing_a_list():
39    a_list = [0, 1, 2, 'n']
40    assert_equal(text(a_list), f'I got: {a_list}')
41
42
43def test_passing_a_set():
44    assert_equal(
45        text({0, 1, 2, 'n'}),
46        'I got: {0, 1, 2, "n"}'
47    )
48
49
50# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: {0, 1, 2, 'n'}"
            == 'I got: {0, 1, 2, "n"}'

GREEN: make it pass

  • I change the set in my expectation to match reality

    43def test_passing_a_set():
44    assert_equal(
45        text({0, 1, 2, 'n'}),
46        # 'I got: {0, 1, 2, "n"}'
47        "I got: {0, 1, 2, 'n'}"
48    )
49
50
51# Exceptions seen

  • I use ctrl/command+s (Windows & Linux/MacOS) to run the test a few times

    • if the result of text({0, 1, 2, 'n'}) is equal to "I got: {0, 1, 2, 'n'}" the test passes because Python uses the string representation of the object in the curly braces { }

      text({0, 1, 2, 'n'}) -> "I got: {0, 1, 2, 'n'}"
└── def text(the_input):
    ├── the_input = {0, 1, 2, 'n'}
    └── return f'I got: {  the_input  }'
        return  'I got:  {0, 1, 2, 'n'}'

    • if the result of text({0, 1, 2, 'n'}) is NOT equal to "I got: {0, 1, 2, 'n'}", the terminal shows AssertionError, for example

      E       assert "I got: {0, 'n', 2, 1}"
            == "I got: {0, 1, 2, 'n'}"

    Python cannot guarantee the order of the things in the set and the order matters for the assertion that is comparing the strings because

    • these two are the same set

      {0, 'n', 2, 1} == {0, 1, 2, 'n'}

    • these two are not the same string

      "{0, 'n', 2, 1}" != "{0, 1, 2, 'n'}"

  • I add a variable for {0, 1, 2, 'n'}

    43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(
46        text({0, 1, 2, 'n'}),
47        # 'I got: {0, 1, 2, "n"}'
48        "I got: {0, 1, 2, 'n'}"
49    )
50
51
52# Exceptions seen

  • I use the variable to remove repetition of {0, 1, 2, 'n'}

    43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(
46        # text({0, 1, 2, 'n'}),
47        # 'I got: {0, 1, 2, "n"}'
48        # "I got: {0, 1, 2, 'n'}"
49        text(a_set), 'I got: a_set'
50    )
51
52
53# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: {0, 1, 2, 'n'}"
            == 'I got: a_set'

  • I change my expectation to an f-string

    43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(
46        # text({0, 1, 2, 'n'}),
47        # 'I got: {0, 1, 2, "n"}'
48        # "I got: {0, 1, 2, 'n'}"
49        # text(a_set), 'I got: a_set'
50        text(a_set), f'I got: {a_set}'
51    )
52
53
54# Exceptions seen

    • I use ctrl/command+s (Windows & Linux/MacOS) to run the test a few times and the test stays green with no random failures because Python uses the string representation of the object in the curly braces { }.

    • It can guarantee the order when I use a variable and the f-string to refer to the same exact set.

REFACTOR: make it better

  • I remove the commented lines from test_passing_a_set

    43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(text(a_set), f'I got: {a_set}')
46
47
48# Exceptions seen

  • I add a git commit message in the other terminal

    git commit --all --message \
'add test_passing_a_set'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a set as input to a function.

test_passing_a_dictionary

Can I pass a dictionary (any key-value pairs in curly braces { } separated by commas) as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a test for a dictionary to test_telephone.py

    43def test_passing_a_set():
44    a_set = {0, 1, 2, 'n'}
45    assert_equal(text(a_set), f'I got: {a_set}')
46
47
48def test_passing_a_dictionary():
49    reality = text({
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    })
53    my_expectation = (
54        "I got: "
55        "{key0: value0, keyN: [0, 1, 2, n]}"
56    )
57    assert_equal(reality, my_expectation)
58
59
60# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: {'key..., 1, 2, 'n']}"
            == 'I got: {key0...[0, 1, 2, n]}'

    I want more detail in my error messages.

GREEN: make it pass

I change my_expectation to match reality

48def test_passing_a_dictionary():
49    reality = text({
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    })
53    my_expectation = (
54        "I got: "
55        # "{key0: value0, keyN: [0, 1, 2, n]}"
56        "{'key0': 'value0', 'keyN': [0, 1, 2, 'n']}"
57    )
58    assert_equal(reality, my_expectation)
59
60
61# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text({
    'key0': 'value0', 'keyN': [0, 1, 2, 'n'],}
) -> ("I got: {'key0': 'value0',"
│              'keyN': [0, 1, 2, 'n']}")
└── def text(the_input):
    ├── the_input = {
    │       'key0': 'value0', 'keyN': [0, 1, 2, 'n']
    │   }
    └── return f'I got: {       the_input        }'
        return ("I got: {'key0': 'value0',"
                         'keyN': [0, 1, 2, 'n']}")

REFACTOR: make it better

  • I add a variable for {'key0': 'value0', 'keyN': [0, 1, 2, 'n'],}

    48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    reality = text({
54        'key0': 'value0',
55        'keyN': [0, 1, 2, 'n'],
56    })

  • I use the variable to remove repetition of {'key0': 'value0', 'keyN': [0, 1, 2, 'n'],}

    48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    # reality = text({
54    #     'key0': 'value0',
55    #     'keyN': [0, 1, 2, 'n'],
56    # })
57    # my_expectation = (
58    #     "I got: "
59    #     # "{key0: value0, keyN: [0, 1, 2, n]}"
60    #     "{'key0': 'value0', 'keyN': [0, 1, 2, 'n']}"
61    # )
62    reality = text(a_dictionary)
63    my_expectation = 'I got: {a_dictionary}'
64    assert_equal(reality, my_expectation)
65
66
67# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: {'key..., 1, 2, 'n']}"
            == 'I got: {a_dictionary}'

  • I change my_expectation to an f-string

    48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    # reality = text({
54    #     'key0': 'value0',
55    #     'keyN': [0, 1, 2, 'n'],
56    # })
57    # my_expectation = (
58    #     "I got: "
59    #     # "{key0: value0, keyN: [0, 1, 2, n]}"
60    #     "{'key0': 'value0', 'keyN': [0, 1, 2, 'n']}"
61    # )
62    reality = text(a_dictionary)
63    # my_expectation = 'I got: {a_dictionary}'
64    my_expectation = f'I got: {a_dictionary}'
65    assert_equal(reality, my_expectation)
66
67
68# Exceptions seen

    the test passes.

  • I remove the commented lines from test_passing_a_dictionary

    48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    reality = text(a_dictionary)
54    my_expectation = f'I got: {a_dictionary}'
55    assert_equal(reality, my_expectation)
56
57
58# Exceptions seen

  • I add a git commit message in the other terminal

    git commit -am \
'add test_passing_a_dictionary'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass a dictionary as input to a function.

test_passing_a_class

Can I pass any object as input to a function?

RED: make it fail

  • I go back to the terminal where the tests are running

  • I add a failing test to see what happens when I pass a class from a test to the text function, to test_telephone.py

    48def test_passing_a_dictionary():
49    a_dictionary = {
50        'key0': 'value0',
51        'keyN': [0, 1, 2, 'n'],
52    }
53    reality = text(a_dictionary)
54    my_expectation = f'I got: {a_dictionary}'
55    assert_equal(reality, my_expectation)
56
57
58def test_passing_a_class():
59    assert_equal(text(object), 'I got: object')
60
61
62# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'object'>"
            == 'I got: object'

    object is the mother class that all Python objects come from because everything in Python is an object.

GREEN: make it pass

I change my expectation to match reality

58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63
64
65# Exceptions seen

the test passes because Python uses the string representation of the object in the curly braces { }

text(object) -> "I got: <class 'object'>"
└── def text(the_input):
    ├── the_input = object
    └── return f'I got: {   the_input   }'
        return  "I got:  <class 'object'>"

REFACTOR: make it better

  • I add an assertion for bool (the class for booleans)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    assert_equal(text(bool), 'I got: bool')
64
65
66# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'bool'>"
            == 'I got: bool'

  • I change my expectation to match reality for bool

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65
66
67# Exceptions seen

    the test passes.

  • I add an assertion for int (the object for whole numbers without decimals)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    assert_equal(text(int), 'I got: int')
66
67
68# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'int'>"
            == 'I got: int'

  • I change my expectation to match reality for int

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67
68
69# Exceptions seen

    the test passes.

  • I add an assertion for float (the object for binary floating point decimal numbers)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    assert_equal(text(float), 'I got: float')
68
69
70# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'float'>"
            == 'I got: float'

  • I change my expectation to match reality for float

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69
70
71# Exceptions seen

    the test passes.

  • I add an assertion for str (the object for anything in quotes)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    assert_equal(text(str), 'I got: str')
70
71
72# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'str'>"
            == 'I got: str'

  • I change my expectation to match reality for str

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71
72
73# Exceptions seen

    the test passes.

  • I add an assertion for tuple (the object for anything in parentheses ( ) separated by a comma)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    assert_equal(text(tuple), 'I got: tuple')
72
73
74# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'tuple'>"
            == 'I got: tuple'

  • I change my expectation to match reality for tuple

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73
74
75# Exceptions seen

    the test passes.

  • I add an assertion for list (the object for anything in square brackets ‘[ ]’)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    assert_equal(text(list), 'I got: list')
74
75
76# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'list'>"
            == 'I got: list'

  • I change my expectation to match reality for list

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    # assert_equal(text(list), 'I got: list')
74    assert_equal(text(list), "I got: <class 'list'>")
75
76
77# Exceptions seen

    the test passes.

  • I add an assertion for set (the object for anything in curly braces { }, not key-value pairs)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    # assert_equal(text(list), 'I got: list')
74    assert_equal(text(list), "I got: <class 'list'>")
75    assert_equal(text(set), 'I got: set')
76
77
78# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'set'>"
            == 'I got: set'

  • I change my expectation to match reality for set

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    # assert_equal(text(list), 'I got: list')
74    assert_equal(text(list), "I got: <class 'list'>")
75    # assert_equal(text(set), 'I got: set')
76    assert_equal(text(set), "I got: <class 'set'>")
77
78
79# Exceptions seen

    the test passes.

  • I add an assertion for dict (the object for key-value pairs in curly braces ‘{ }’ separated by commas)

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    # assert_equal(text(list), 'I got: list')
74    assert_equal(text(list), "I got: <class 'list'>")
75    # assert_equal(text(set), 'I got: set')
76    assert_equal(text(set), "I got: <class 'set'>")
77    assert_equal(text(dict), 'I got: dict')
78
79
80# Exceptions seen

    the terminal is my friend, and shows AssertionError

    E       assert "I got: <class 'dict'>"
            == 'I got: dict'

  • I change my expectation to match reality for dict

    58def test_passing_a_class():
59    # assert_equal(text(object), 'I got: object')
60    assert_equal(
61        text(object), "I got: <class 'object'>"
62    )
63    # assert_equal(text(bool), 'I got: bool')
64    assert_equal(text(bool), "I got: <class 'bool'>")
65    # assert_equal(text(int), 'I got: int')
66    assert_equal(text(int), "I got: <class 'int'>")
67    # assert_equal(text(float), 'I got: float')
68    assert_equal(text(float), "I got: <class 'float'>")
69    # assert_equal(text(str), 'I got: str')
70    assert_equal(text(str), "I got: <class 'str'>")
71    # assert_equal(text(tuple), 'I got: tuple')
72    assert_equal(text(tuple), "I got: <class 'tuple'>")
73    # assert_equal(text(list), 'I got: list')
74    assert_equal(text(list), "I got: <class 'list'>")
75    # assert_equal(text(set), 'I got: set')
76    assert_equal(text(set), "I got: <class 'set'>")
77    # assert_equal(text(dict), 'I got: dict')
78    assert_equal(text(dict), "I got: <class 'dict'>")
79
80
81# Exceptions seen

    all the tests are passing because Python uses the string representation of the object in the curly braces { }

    text(any object) ->  "I got: <class 'any object'>"
└── def text(the_input):
    ├── the_input = dict
    └── return f'I got: {     the_input      }'
        return  "I got:  <class 'any object'> "

  • I remove the commented lines from test_passing_a_class

    58def test_passing_a_class():
59    assert_equal(
60        text(object), "I got: <class 'object'>"
61    )
62    assert_equal(text(bool), "I got: <class 'bool'>")
63    assert_equal(text(int), "I got: <class 'int'>")
64    assert_equal(text(float), "I got: <class 'float'>")
65    assert_equal(text(str), "I got: <class 'str'>")
66    assert_equal(text(tuple), "I got: <class 'tuple'>")
67    assert_equal(text(list), "I got: <class 'list'>")
68    assert_equal(text(set), "I got: <class 'set'>")
69    assert_equal(text(dict), "I got: <class 'dict'>")
70
71
72# Exceptions seen
73# AssertionError
74# NameError
75# TypeError

  • I add a git commit message in the other terminal

    git commit --all --message \
'add test_passing_a_class'

    the terminal shows a summary of the changes then goes back to the command line.

I can pass any object as input to a function.

close the project

  • I close test_telephone.py

  • I click in the terminal where the tests are running

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

  • I change directory to the parent of telephone

    cd ..

    the terminal shows

    .../pumping_python

    I am back in the pumping_python directory.

review

  • I ran tests to see what happens when I pass objects from a test to a program and place them in an f-string which is one way to do string interpolation.

  • I still have the problem where I wrote the assert_equal function in this project, even though I wrote it in previous projects. There has to be a better way where I can write the function once, then use it any time or anywhere I want.

code from the chapter

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

what is next?

would you like to test separating the tests from the solutions?

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