test person with unittest

I want to use the unittest library in the person project.

preview

I have these tests by the end of the chapter

person/tests/test_person.py
  1import src.person
  2import unittest
  3
  4
  5class TestPerson(unittest.TestCase):
  6
  7    def test_joe(self):
  8        first_name = 'joe'
  9        last_name = 'blow'
 10        sex = 'M'
 11        year_of_birth = 1996
 12
 13        reality = src.person.factory(
 14            first_name=first_name,
 15            last_name=last_name,
 16            sex=sex,
 17            year_of_birth=year_of_birth,
 18        )
 19        my_expectation = (
 20            f'{first_name}, {last_name},'
 21            f' {sex}, {year_of_birth}'
 22        )
 23        assert reality == my_expectation
 24        self.assertEqual(reality, my_expectation)
 25
 26        reality = src.person.say_hello(
 27            first_name=first_name,
 28            last_name=last_name,
 29            year_of_birth=year_of_birth,
 30        )
 31        my_expectation = (
 32            f'Hello, my name is {first_name}'
 33            f' {last_name} and I am'
 34            f' {2026-year_of_birth}.'
 35        )
 36        assert reality == my_expectation
 37        self.assertEqual(reality, my_expectation)
 38
 39        joe = src.person.Person(
 40            first_name=first_name,
 41            last_name=last_name,
 42            sex=sex,
 43            year_of_birth=year_of_birth,
 44        )
 45
 46        reality = joe.say_hello()
 47        assert reality == my_expectation
 48        self.assertEqual(reality, my_expectation)
 49
 50    def test_jane(self):
 51        first_name = 'jane'
 52        last_name = 'doe'
 53        sex = 'F'
 54        year_of_birth = 1991
 55
 56        reality = src.person.factory(
 57            first_name=first_name,
 58            last_name=last_name,
 59            sex=sex,
 60            year_of_birth=year_of_birth,
 61        )
 62        my_expectation = (
 63            f'{first_name}, {last_name},'
 64            f' {sex}, {year_of_birth}'
 65        )
 66        assert reality == my_expectation
 67        self.assertEqual(reality, my_expectation)
 68
 69        reality = src.person.say_hello(
 70            first_name=first_name,
 71            last_name=last_name,
 72            year_of_birth=year_of_birth,
 73        )
 74        my_expectation = (
 75            f'Hello, my name is {first_name}'
 76            f' {last_name} and I am'
 77            f' {2026-year_of_birth}.'
 78        )
 79        assert reality == my_expectation
 80        self.assertEqual(reality, my_expectation)
 81
 82        jane = src.person.Person(
 83            first_name=first_name,
 84            last_name=last_name,
 85            sex=sex,
 86            year_of_birth=year_of_birth,
 87        )
 88
 89        reality = jane.say_hello()
 90        assert reality == my_expectation
 91        self.assertEqual(reality, my_expectation)
 92
 93    def test_john(self):
 94        first_name = 'john'
 95        last_name = 'smith'
 96        sex = 'M'
 97        year_of_birth = 1580
 98
 99        reality = src.person.factory(
100            first_name=first_name,
101            last_name=last_name,
102            sex=sex,
103            year_of_birth=year_of_birth,
104        )
105        my_expectation = (
106            f'{first_name}, {last_name},'
107            f' {sex}, {year_of_birth}'
108        )
109        assert reality == my_expectation
110        self.assertEqual(reality, my_expectation)
111
112        reality = src.person.say_hello(
113            first_name=first_name,
114            last_name=last_name,
115            year_of_birth=year_of_birth,
116        )
117        my_expectation = (
118            f'Hello, my name is {first_name}'
119            f' {last_name} and I am'
120            f' {2026-year_of_birth}.'
121        )
122        assert reality == my_expectation
123        self.assertEqual(reality, my_expectation)
124
125        john = src.person.Person(
126            first_name=first_name,
127            last_name=last_name,
128            sex=sex,
129            year_of_birth=year_of_birth,
130        )
131
132        reality = john.say_hello()
133        assert reality == my_expectation
134        self.assertEqual(reality, my_expectation)
135
136    def test_mary(self):
137        first_name = 'mary'
138        last_name = 'public'
139        sex = 'F'
140        year_of_birth = 2000
141
142        reality = src.person.factory(
143            first_name=first_name,
144            last_name=last_name,
145            sex=sex,
146            year_of_birth=year_of_birth,
147        )
148        my_expectation = (
149            f'{first_name}, {last_name},'
150            f' {sex}, {year_of_birth}'
151        )
152        assert reality == my_expectation
153        self.assertEqual(reality, my_expectation)
154
155        reality = src.person.say_hello(
156            first_name=first_name,
157            last_name=last_name,
158            year_of_birth=year_of_birth,
159        )
160        my_expectation = (
161            f'Hello, my name is {first_name}'
162            f' {last_name} and I am'
163            f' {2026-year_of_birth}.'
164        )
165        assert reality == my_expectation
166        self.assertEqual(reality, my_expectation)
167
168        mary = src.person.Person(
169            first_name=first_name,
170            last_name=last_name,
171            sex=sex,
172            year_of_birth=year_of_birth,
173        )
174
175        reality = mary.say_hello()
176        assert reality == my_expectation
177        self.assertEqual(reality, my_expectation)
178
179    def test_dir_person_class(self):
180        reality = dir(src.person.Person)
181        my_expectation = [
182            '__class__',
183            '__delattr__',
184            '__dict__',
185            '__dir__',
186            '__doc__',
187            '__eq__',
188            '__firstlineno__',
189            '__format__',
190            '__ge__',
191            '__getattribute__',
192            '__getstate__',
193            '__gt__',
194            '__hash__',
195            '__init__',
196            '__init_subclass__',
197            '__le__',
198            '__lt__',
199            '__module__',
200            '__ne__',
201            '__new__',
202            '__reduce__',
203            '__reduce_ex__',
204            '__repr__',
205            '__setattr__',
206            '__sizeof__',
207            '__static_attributes__',
208            '__str__',
209            '__subclasshook__',
210            '__weakref__',
211            'say_hello'
212        ]
213        assert reality == my_expectation
214        self.assertEqual(reality, my_expectation)
215
216    def test_dir_person_instance(self):
217        an_instance_of_person = src.person.Person(
218            first_name='first_name',
219            last_name='last_name',
220            sex='M',
221            year_of_birth=2026,
222        )
223
224        reality = dir(an_instance_of_person)
225        my_expectation = [
226            '__class__',
227            '__delattr__',
228            '__dict__',
229            '__dir__',
230            '__doc__',
231            '__eq__',
232            '__firstlineno__',
233            '__format__',
234            '__ge__',
235            '__getattribute__',
236            '__getstate__',
237            '__gt__',
238            '__hash__',
239            '__init__',
240            '__init_subclass__',
241            '__le__',
242            '__lt__',
243            '__module__',
244            '__ne__',
245            '__new__',
246            '__reduce__',
247            '__reduce_ex__',
248            '__repr__',
249            '__setattr__',
250            '__sizeof__',
251            '__static_attributes__',
252            '__str__',
253            '__subclasshook__',
254            '__weakref__',
255            'first_name',
256            'last_name',
257            'say_hello',
258            'sex',
259            'year_of_birth',
260        ]
261        assert reality == my_expectation
262        self.assertEqual(reality, my_expectation)
263
264
265# Exceptions seen
266# AssertionError
267# NameError
268# TypeError
269# AttributeError
270# SyntaxError

open the project

  • I open a terminal

  • I change directory to the project

    cd person

  • I open test_person.py from the tests folder

  • I use pytest-watcher to run the tests automatically

    uv run pytest-watcher . --now

    the terminal shows

    tests/test_person.py ......                         [100%]

=================== 6 passed in A.BCs ====================

add TestPerson class

RED: make it fail

I add a class named TestPerson to test_person.py

 1import src.person
 2
 3
 4class TestPerson(object):
 5
 6    def test_failure(self):
 7        self.assertEqual(False, True)
 8
 9
10def test_joe():

the terminal is my friend, and shows AttributeError

AttributeError: 'TestPerson' object
                has no attribute 'assertEqual'

GREEN: make it pass

  • I add unittest.TestCase as the parent class of TestPerson

    1import src.person
2
3
4# class TestPerson(object):
5class TestPerson(unittest.TestCase):

    the terminal is my friend, and shows NameError

    NameError: name 'unittest' is not defined.
           Did you forget to import 'unittest'?

  • I add an import statement at the top of the file

    1import src.person
2import unittest
3
4
5# class TestPerson(object):
6class TestPerson(unittest.TestCase):

    the terminal is my friend, and shows AssertionError

    AssertionError: False != True

  • I change False to True in the assertion

     5# class TestPerson(object):
 6class TestPerson(unittest.TestCase):
 7
 8    def test_failure(self):
 9        # self.assertEqual(False, True)
10        self.assertEqual(True, True)
11
12
13def test_joe():

    the test passes.

REFACTOR: make it better

  • I remove the commented lines

     1import src.person
 2import unittest
 3
 4
 5class TestPerson(unittest.TestCase):
 6
 7    def test_failure(self):
 8        self.assertEqual(True, True)
 9
10
11def test_joe():

  • I open a new terminal then make sure I am in the person folder

    cd person

  • I add a git commit message in the new terminal

    git commit -am \
'add TestPerson class'

test_joe with unittest

RED: make it fail

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

  • I move test_joe to make it a method of the TestPerson class and replace test_failure

     5class TestPerson(unittest.TestCase):
 6
 7    def test_joe():
 8        first_name = 'joe'
 9        last_name = 'blow'
10        sex = 'M'
11        year_of_birth = 1996
12
13        reality = src.person.factory(
14            first_name=first_name,
15            last_name=last_name,
16            sex=sex,
17            year_of_birth=year_of_birth,
18        )
19        my_expectation = (
20            f'{first_name}, {last_name},'
21            f' {sex}, {year_of_birth}'
22        )
23        assert reality == my_expectation
24
25        reality = src.person.say_hello(
26            first_name=first_name,
27            last_name=last_name,
28            year_of_birth=year_of_birth,
29        )
30        my_expectation = (
31            f'Hello, my name is {first_name}'
32            f' {last_name} and I am'
33            f' {2026-year_of_birth}.'
34        )
35        assert reality == my_expectation
36
37        joe = src.person.Person(
38            first_name=first_name,
39            last_name=last_name,
40            sex=sex,
41            year_of_birth=year_of_birth,
42        )
43
44        reality = joe.say_hello()
45        assert reality == my_expectation
46
47
48def test_jane():

    the terminal is my friend, and shows TypeError

    TypeError: TestPerson.test_joe() takes
           0 positional arguments but 1 was given

    because a method of an instance takes the instance of the class (self) it belongs to as the first argument.

GREEN: make it pass

I add self to the parentheses of test_joe

7    # def test_joe():
8    def test_joe(self):

the test is green again.

REFACTOR: make it better

  • I add a call to the assertNotEqual method for the factory function

     7    # def test_joe():
 8    def test_joe(self):
 9        first_name = 'joe'
10        last_name = 'blow'
11        sex = 'M'
12        year_of_birth = 1996
13
14        reality = src.person.factory(
15            first_name=first_name,
16            last_name=last_name,
17            sex=sex,
18            year_of_birth=year_of_birth,
19        )
20        my_expectation = (
21            f'{first_name}, {last_name},'
22            f' {sex}, {year_of_birth}'
23        )
24        assert reality == my_expectation
25        self.assertNotEqual(reality, my_expectation)

    the terminal is my friend, and shows AssertionError

    AssertionError: 'joe, blow, M, 1996'
             == 'joe, blow, M, 1996'

  • I change assertNotEqual to assertEqual

    24        assert reality == my_expectation
25        # self.assertNotEqual(reality, my_expectation)
26        self.assertEqual(reality, my_expectation)
27
28        reality = src.person.say_hello(
29            first_name=first_name,
30            last_name=last_name,
31            year_of_birth=year_of_birth,
32        )
33        my_expectation = (
34            f'Hello, my name is {first_name}'
35            f' {last_name} and I am'
36            f' {2026-year_of_birth}.'
37        )
38        assert reality == my_expectation

    the test passes.

  • I add a call to the assertNotEqual method for the say_hello function

    28        reality = src.person.say_hello(
29            first_name=first_name,
30            last_name=last_name,
31            year_of_birth=year_of_birth,
32        )
33        my_expectation = (
34            f'Hello, my name is {first_name}'
35            f' {last_name} and I am'
36            f' {2026-year_of_birth}.'
37        )
38        assert reality == my_expectation
39        self.assertNotEqual(reality, my_expectation)

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is joe blow and I am 30.'
             == 'Hello, my name is joe blow and I am 30.'

  • I change assertNotEqual to assertEqual

    38        assert reality == my_expectation
39        # self.assertNotEqual(reality, my_expectation)
40        self.assertEqual(reality, my_expectation)
41
42        joe = src.person.Person(
43            first_name=first_name,
44            last_name=last_name,
45            sex=sex,
46            year_of_birth=year_of_birth,
47        )
48
49        reality = joe.say_hello()

    the test passes.

  • I add a call to the assertNotEqual method for the say_hello method of the Person class

    49        reality = joe.say_hello()
50        assert reality == my_expectation
51        self.assertNotEqual(reality, my_expectation)
52
53
54def test_jane():

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is joe blow and I am 30.'
             == 'Hello, my name is joe blow and I am 30.'

  • I change assertNotEqual to assertEqual

    49        reality = joe.say_hello()
50        assert reality == my_expectation
51        # self.assertNotEqual(reality, my_expectation)
52        self.assertEqual(reality, my_expectation)
53
54
55def test_jane():

    the test passes.

  • I remove the commented lines from test_joe

     5class TestPerson(unittest.TestCase):
 6
 7    def test_joe(self):
 8        first_name = 'joe'
 9        last_name = 'blow'
10        sex = 'M'
11        year_of_birth = 1996
12
13        reality = src.person.factory(
14            first_name=first_name,
15            last_name=last_name,
16            sex=sex,
17            year_of_birth=year_of_birth,
18        )
19        my_expectation = (
20            f'{first_name}, {last_name},'
21            f' {sex}, {year_of_birth}'
22        )
23        assert reality == my_expectation
24        self.assertEqual(reality, my_expectation)
25
26        reality = src.person.say_hello(
27            first_name=first_name,
28            last_name=last_name,
29            year_of_birth=year_of_birth,
30        )
31        my_expectation = (
32            f'Hello, my name is {first_name}'
33            f' {last_name} and I am'
34            f' {2026-year_of_birth}.'
35        )
36        assert reality == my_expectation
37        self.assertEqual(reality, my_expectation)
38
39        joe = src.person.Person(
40            first_name=first_name,
41            last_name=last_name,
42            sex=sex,
43            year_of_birth=year_of_birth,
44        )
45
46        reality = joe.say_hello()
47        assert reality == my_expectation
48        self.assertEqual(reality, my_expectation)
49
50
51def test_jane():

  • I add a git commit message in the other terminal

    git commit -am 'move test_joe to TestPerson'

test_jane with unittest

RED: make it fail

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

  • I move test_jane to make it a method of the TestPerson class

    46        reality = joe.say_hello()
47        assert reality == my_expectation
48        self.assertEqual(reality, my_expectation)
49
50    def test_jane():
51        first_name = 'jane'
52        last_name = 'doe'
53        sex = 'F'
54        year_of_birth = 1991
55
56        reality = src.person.factory(
57            first_name=first_name,
58            last_name=last_name,
59            sex=sex,
60            year_of_birth=year_of_birth,
61        )
62        my_expectation = (
63            f'{first_name}, {last_name},'
64            f' {sex}, {year_of_birth}'
65        )
66        assert reality == my_expectation
67
68        reality = src.person.say_hello(
69            first_name=first_name,
70            last_name=last_name,
71            year_of_birth=year_of_birth,
72        )
73        my_expectation = (
74            f'Hello, my name is {first_name}'
75            f' {last_name} and I am'
76            f' {2026-year_of_birth}.'
77        )
78        assert reality == my_expectation
79
80        jane = src.person.Person(
81            first_name=first_name,
82            last_name=last_name,
83            sex=sex,
84            year_of_birth=year_of_birth,
85        )
86
87        reality = jane.say_hello()
88        assert reality == my_expectation
89
90
91def test_john():

    the terminal is my friend, and shows TypeError

    TypeError: TestPerson.test_jane() takes
           0 positional arguments but 1 was given

    because …

GREEN: make it pass

I add self to the parentheses of test_jane

46        reality = joe.say_hello()
47        assert reality == my_expectation
48        self.assertEqual(reality, my_expectation)
49
50    # def test_jane():
51    def test_jane(self):

the test passes.

REFACTOR: make it better

  • I add calls to the assertNotEqual method in test_jane

    50    # def test_jane():
51    def test_jane(self):
52        first_name = 'jane'
53        last_name = 'doe'
54        sex = 'F'
55        year_of_birth = 1991
56
57        reality = src.person.factory(
58            first_name=first_name,
59            last_name=last_name,
60            sex=sex,
61            year_of_birth=year_of_birth,
62        )
63        my_expectation = (
64            f'{first_name}, {last_name},'
65            f' {sex}, {year_of_birth}'
66        )
67        assert reality == my_expectation
68        self.assertNotEqual(reality, my_expectation)
69
70        reality = src.person.say_hello(
71            first_name=first_name,
72            last_name=last_name,
73            year_of_birth=year_of_birth,
74        )
75        my_expectation = (
76            f'Hello, my name is {first_name}'
77            f' {last_name} and I am'
78            f' {2026-year_of_birth}.'
79        )
80        assert reality == my_expectation
81        self.assertNotEqual(reality, my_expectation)
82
83        jane = src.person.Person(
84            first_name=first_name,
85            last_name=last_name,
86            sex=sex,
87            year_of_birth=year_of_birth,
88        )
89
90        reality = jane.say_hello()
91        assert reality == my_expectation
92        self.assertNotEqual(reality, my_expectation)
93
94
95def test_john():

    the terminal is my friend, and shows AssertionError

    AssertionError: 'jane, doe, F, 1991'
             == 'jane, doe, F, 1991'

  • I change assertNotEqual to assertEqual for the factory function, in test_jane

    67        assert reality == my_expectation
68        # self.assertNotEqual(reality, my_expectation)
69        self.assertEqual(reality, my_expectation)
70
71        reality = src.person.say_hello(
72            first_name=first_name,
73            last_name=last_name,
74            year_of_birth=year_of_birth,
75        )
76        my_expectation = (
77            f'Hello, my name is {first_name}'
78            f' {last_name} and I am'
79            f' {2026-year_of_birth}.'
80        )
81        assert reality == my_expectation
82        self.assertNotEqual(reality, my_expectation)

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is jane doe and I am 35.'
             == 'Hello, my name is jane doe and I am 35.'

  • I change assertNotEqual to assertEqual for the say_hello function, in test_jane

    81        assert reality == my_expectation
82        # self.assertNotEqual(reality, my_expectation)
83        self.assertEqual(reality, my_expectation)
84
85        jane = src.person.Person(
86            first_name=first_name,
87            last_name=last_name,
88            sex=sex,
89            year_of_birth=year_of_birth,
90        )
91
92        reality = jane.say_hello()

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is jane doe and I am 35.'
             == 'Hello, my name is jane doe and I am 35.'

  • I change assertNotEqual to assertEqual for the say_hello method of the Person class, in test_jane

    92        reality = jane.say_hello()
93        assert reality == my_expectation
94        # self.assertNotEqual(reality, my_expectation)
95        self.assertEqual(reality, my_expectation)
96
97
98def test_john():

    the test passes.

  • I remove the commented lines from test_jane

    48        self.assertEqual(reality, my_expectation)
49
50    def test_jane(self):
51        first_name = 'jane'
52        last_name = 'doe'
53        sex = 'F'
54        year_of_birth = 1991
55
56        reality = src.person.factory(
57            first_name=first_name,
58            last_name=last_name,
59            sex=sex,
60            year_of_birth=year_of_birth,
61        )
62        my_expectation = (
63            f'{first_name}, {last_name},'
64            f' {sex}, {year_of_birth}'
65        )
66        assert reality == my_expectation
67        self.assertEqual(reality, my_expectation)
68
69        reality = src.person.say_hello(
70            first_name=first_name,
71            last_name=last_name,
72            year_of_birth=year_of_birth,
73        )
74        my_expectation = (
75            f'Hello, my name is {first_name}'
76            f' {last_name} and I am'
77            f' {2026-year_of_birth}.'
78        )
79        assert reality == my_expectation
80        self.assertEqual(reality, my_expectation)
81
82        jane = src.person.Person(
83            first_name=first_name,
84            last_name=last_name,
85            sex=sex,
86            year_of_birth=year_of_birth,
87        )
88
89        reality = jane.say_hello()
90        assert reality == my_expectation
91        self.assertEqual(reality, my_expectation)
92
93
94def test_john():

  • I add a git commit message in the other terminal

    git commit -am 'move test_jane to TestPerson'

test_john with unittest

RED: make it fail

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

  • I move test_john to make it a method of the TestPerson class

     89        reality = jane.say_hello()
 90        assert reality == my_expectation
 91        self.assertEqual(reality, my_expectation)
 92
 93    def test_john():
 94        first_name = 'john'
 95        last_name = 'smith'
 96        sex = 'M'
 97        year_of_birth = 1580
 98
 99        reality = src.person.factory(
100            first_name=first_name,
101            last_name=last_name,
102            sex=sex,
103            year_of_birth=year_of_birth,
104        )
105        my_expectation = (
106            f'{first_name}, {last_name},'
107            f' {sex}, {year_of_birth}'
108        )
109        assert reality == my_expectation
110
111        reality = src.person.say_hello(
112            first_name=first_name,
113            last_name=last_name,
114            year_of_birth=year_of_birth,
115        )
116        my_expectation = (
117            f'Hello, my name is {first_name}'
118            f' {last_name} and I am'
119            f' {2026-year_of_birth}.'
120        )
121        assert reality == my_expectation
122
123        john = src.person.Person(
124            first_name=first_name,
125            last_name=last_name,
126            sex=sex,
127            year_of_birth=year_of_birth,
128        )
129
130        reality = john.say_hello()
131        assert reality == my_expectation
132
133
134def test_mary():

    the terminal is my friend, and shows TypeError

    TypeError: TestPerson.test_john() takes
           0 positional arguments but 1 was given

    because a method of an instance takes the instance of the class (self) it belongs to as the first argument.

GREEN: make it pass

I add self to the parentheses of test_john

89        reality = jane.say_hello()
90        assert reality == my_expectation
91        self.assertEqual(reality, my_expectation)
92
93    # def test_john():
94    def test_john(self):

green again.

REFACTOR: make it better

  • I add calls to the assertNotEqual method in test_john

     93    # def test_john():
 94    def test_john(self):
 95        first_name = 'john'
 96        last_name = 'smith'
 97        sex = 'M'
 98        year_of_birth = 1580
 99
100        reality = src.person.factory(
101            first_name=first_name,
102            last_name=last_name,
103            sex=sex,
104            year_of_birth=year_of_birth,
105        )
106        my_expectation = (
107            f'{first_name}, {last_name},'
108            f' {sex}, {year_of_birth}'
109        )
110        assert reality == my_expectation
111        self.assertNotEqual(reality, my_expectation)
112
113        reality = src.person.say_hello(
114            first_name=first_name,
115            last_name=last_name,
116            year_of_birth=year_of_birth,
117        )
118        my_expectation = (
119            f'Hello, my name is {first_name}'
120            f' {last_name} and I am'
121            f' {2026-year_of_birth}.'
122        )
123        assert reality == my_expectation
124        self.assertNotEqual(reality, my_expectation)
125
126        john = src.person.Person(
127            first_name=first_name,
128            last_name=last_name,
129            sex=sex,
130            year_of_birth=year_of_birth,
131        )
132
133        reality = john.say_hello()
134        assert reality == my_expectation
135        self.assertNotEqual(reality, my_expectation)
136
137
138def test_mary():

    the terminal is my friend, and shows AssertionError

    AssertionError: 'john, smith, M, 1580'
             == 'john, smith, M, 1580'

  • I change assertNotEqual to assertEqual for the factory function, in test_john

    110        assert reality == my_expectation
111        # self.assertNotEqual(reality, my_expectation)
112        self.assertEqual(reality, my_expectation)
113
114        reality = src.person.say_hello(
115            first_name=first_name,
116            last_name=last_name,
117            year_of_birth=year_of_birth,
118        )
119        my_expectation = (
120            f'Hello, my name is {first_name}'
121            f' {last_name} and I am'
122            f' {2026-year_of_birth}.'
123        )
124        assert reality == my_expectation
125        self.assertNotEqual(reality, my_expectation)

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is john smith and I am 446.'
             == 'Hello, my name is john smith and I am 446.'

  • I change assertNotEqual to assertEqual for the say_hello function, in test_john

    124        assert reality == my_expectation
125        # self.assertNotEqual(reality, my_expectation)
126        self.assertEqual(reality, my_expectation)
127
128        john = src.person.Person(
129            first_name=first_name,
130            last_name=last_name,
131            sex=sex,
132            year_of_birth=year_of_birth,
133        )
134
135        reality = john.say_hello()

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is john smith and I am 446.'
             == 'Hello, my name is john smith and I am 446.'

  • I change assertNotEqual to assertEqual for the say_hello method of the Person class, in test_john

    135        reality = john.say_hello()
136        assert reality == my_expectation
137        # self.assertNotEqual(reality, my_expectation)
138        self.assertEqual(reality, my_expectation)
139
140
141def test_mary():

    the test passes.

  • I remove the commented lines from test_john

     91        self.assertEqual(reality, my_expectation)
 92
 93    def test_john(self):
 94        first_name = 'john'
 95        last_name = 'smith'
 96        sex = 'M'
 97        year_of_birth = 1580
 98
 99        reality = src.person.factory(
100            first_name=first_name,
101            last_name=last_name,
102            sex=sex,
103            year_of_birth=year_of_birth,
104        )
105        my_expectation = (
106            f'{first_name}, {last_name},'
107            f' {sex}, {year_of_birth}'
108        )
109        assert reality == my_expectation
110        self.assertEqual(reality, my_expectation)
111
112        reality = src.person.say_hello(
113            first_name=first_name,
114            last_name=last_name,
115            year_of_birth=year_of_birth,
116        )
117        my_expectation = (
118            f'Hello, my name is {first_name}'
119            f' {last_name} and I am'
120            f' {2026-year_of_birth}.'
121        )
122        assert reality == my_expectation
123        self.assertEqual(reality, my_expectation)
124
125        john = src.person.Person(
126            first_name=first_name,
127            last_name=last_name,
128            sex=sex,
129            year_of_birth=year_of_birth,
130        )
131
132        reality = john.say_hello()
133        assert reality == my_expectation
134        self.assertEqual(reality, my_expectation)
135
136
137def test_mary():

  • I add a git commit message in the other terminal

    git commit -am 'move test_john to TestPerson'

test_mary with unittest

RED: make it fail

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

  • I move test_mary to make it a method of the TestPerson class

    132        reality = john.say_hello()
133        assert reality == my_expectation
134        self.assertEqual(reality, my_expectation)
135
136    def test_mary():
137        first_name = 'mary'
138        last_name = 'public'
139        sex = 'F'
140        year_of_birth = 2000
141
142        reality = src.person.factory(
143            first_name=first_name,
144            last_name=last_name,
145            sex=sex,
146            year_of_birth=year_of_birth,
147        )
148        my_expectation = (
149            f'{first_name}, {last_name},'
150            f' {sex}, {year_of_birth}'
151        )
152        assert reality == my_expectation
153
154        reality = src.person.say_hello(
155            first_name=first_name,
156            last_name=last_name,
157            year_of_birth=year_of_birth,
158        )
159        my_expectation = (
160            f'Hello, my name is {first_name}'
161            f' {last_name} and I am'
162            f' {2026-year_of_birth}.'
163        )
164        assert reality == my_expectation
165
166        mary = src.person.Person(
167            first_name=first_name,
168            last_name=last_name,
169            sex=sex,
170            year_of_birth=year_of_birth,
171        )
172
173        reality = mary.say_hello()
174        assert reality == my_expectation
175
176
177def test_dir_person_class():

    the terminal is my friend, and shows TypeError

    TypeError: TestPerson.test_mary() takes
           0 positional arguments but 1 was given

    because a method of an instance takes the instance of the class (self) it belongs to as the first argument.

GREEN: make it pass

I add self to the parentheses of test_mary

132        reality = john.say_hello()
133        assert reality == my_expectation
134        self.assertEqual(reality, my_expectation)
135
136    # def test_mary():
137    def test_mary(self):

green.

REFACTOR: make it better

  • I add calls to the assertNotEqual method in test_mary

    136    # def test_mary():
137    def test_mary(self):
138        first_name = 'mary'
139        last_name = 'public'
140        sex = 'F'
141        year_of_birth = 2000
142
143        reality = src.person.factory(
144            first_name=first_name,
145            last_name=last_name,
146            sex=sex,
147            year_of_birth=year_of_birth,
148        )
149        my_expectation = (
150            f'{first_name}, {last_name},'
151            f' {sex}, {year_of_birth}'
152        )
153        assert reality == my_expectation
154        self.assertNotEqual(reality, my_expectation)
155
156        reality = src.person.say_hello(
157            first_name=first_name,
158            last_name=last_name,
159            year_of_birth=year_of_birth,
160        )
161        my_expectation = (
162            f'Hello, my name is {first_name}'
163            f' {last_name} and I am'
164            f' {2026-year_of_birth}.'
165        )
166        assert reality == my_expectation
167        self.assertNotEqual(reality, my_expectation)
168
169        mary = src.person.Person(
170            first_name=first_name,
171            last_name=last_name,
172            sex=sex,
173            year_of_birth=year_of_birth,
174        )
175
176        reality = mary.say_hello()
177        assert reality == my_expectation
178        self.assertNotEqual(reality, my_expectation)
179
180
181def test_dir_person_class():

    the terminal is my friend, and shows AssertionError

    AssertionError: 'mary, public, F, 2000'
             == 'mary, public, F, 2000'

  • I change assertNotEqual to assertEqual for the factory function, in test_mary

    153        assert reality == my_expectation
154        # self.assertNotEqual(reality, my_expectation)
155        self.assertEqual(reality, my_expectation)
156
157        reality = src.person.say_hello(
158            first_name=first_name,
159            last_name=last_name,
160            year_of_birth=year_of_birth,
161        )
162        my_expectation = (
163            f'Hello, my name is {first_name}'
164            f' {last_name} and I am'
165            f' {2026-year_of_birth}.'
166        )
167        assert reality == my_expectation
168        self.assertNotEqual(reality, my_expectation)

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is mary public and I am 26.'
             == 'Hello, my name is mary public and I am 26.'

  • I change assertNotEqual to assertEqual for the say_hello function, in test_mary

    167        assert reality == my_expectation
168        # self.assertNotEqual(reality, my_expectation)
169        self.assertEqual(reality, my_expectation)
170
171        mary = src.person.Person(
172            first_name=first_name,
173            last_name=last_name,
174            sex=sex,
175            year_of_birth=year_of_birth,
176        )
177
178        reality = mary.say_hello()

    the terminal is my friend, and shows AssertionError

    AssertionError: 'Hello, my name is mary public and I am 26.'
             == 'Hello, my name is mary public and I am 26.'

  • I change assertNotEqual to assertEqual for the say_hello method of the Person class, in test_mary

    178        reality = mary.say_hello()
179        assert reality == my_expectation
180        # self.assertNotEqual(reality, my_expectation)
181        self.assertEqual(reality, my_expectation)
182
183
184def test_dir_person_class():

    the test passes.

  • I remove the commented lines from test_mary

    134        self.assertEqual(reality, my_expectation)
135
136    def test_mary(self):
137        first_name = 'mary'
138        last_name = 'public'
139        sex = 'F'
140        year_of_birth = 2000
141
142        reality = src.person.factory(
143            first_name=first_name,
144            last_name=last_name,
145            sex=sex,
146            year_of_birth=year_of_birth,
147        )
148        my_expectation = (
149            f'{first_name}, {last_name},'
150            f' {sex}, {year_of_birth}'
151        )
152        assert reality == my_expectation
153        self.assertEqual(reality, my_expectation)
154
155        reality = src.person.say_hello(
156            first_name=first_name,
157            last_name=last_name,
158            year_of_birth=year_of_birth,
159        )
160        my_expectation = (
161            f'Hello, my name is {first_name}'
162            f' {last_name} and I am'
163            f' {2026-year_of_birth}.'
164        )
165        assert reality == my_expectation
166        self.assertEqual(reality, my_expectation)
167
168        mary = src.person.Person(
169            first_name=first_name,
170            last_name=last_name,
171            sex=sex,
172            year_of_birth=year_of_birth,
173        )
174
175        reality = mary.say_hello()
176        assert reality == my_expectation
177        self.assertEqual(reality, my_expectation)
178
179
180def test_dir_person_class():

  • I add a git commit message in the other terminal

    git commit -am 'move test_mary to TestPerson'

test_dir_person_class with unittest

RED: make it fail

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

  • I move test_dir_person_class to make it a method of the TestPerson class

    175        reality = mary.say_hello()
176        assert reality == my_expectation
177        self.assertEqual(reality, my_expectation)
178
179    def test_dir_person_class():
180        reality = dir(src.person.Person)
181        my_expectation = [

    212        ]
213        assert reality == my_expectation
214
215
216def test_dir_person_instance():

    the terminal is my friend, and shows TypeError

    TypeError:
    TestPerson.test_dir_person_class()
    takes 0 positional arguments but 1 was given

    because a method of an instance takes the instance of the class (self) it belongs to as the first argument.

GREEN: make it pass

I add self to the parentheses of test_dir_person_class

175        reality = mary.say_hello()
176        assert reality == my_expectation
177        self.assertEqual(reality, my_expectation)
178
179    # def test_dir_person_class():
180    def test_dir_person_class(self):

green again.

REFACTOR: make it better

  • I add a call to the assertNotEqual method in test_dir_person_class

    214        assert reality == my_expectation
215        self.assertNotEqual(reality, my_expectation)
216
217
218def test_dir_person_instance():

    the terminal is my friend, and shows AssertionError.

  • I change assertNotEqual to assertEqual in test_dir_person_class

    214        assert reality == my_expectation
215        # self.assertNotEqual(reality, my_expectation)
216        self.assertEqual(reality, my_expectation)
217
218
219def test_dir_person_instance():

    the test passes.

  • I remove the commented lines from test_dir_person_class

    175        reality = mary.say_hello()
176        assert reality == my_expectation
177        self.assertEqual(reality, my_expectation)
178
179    def test_dir_person_class(self):
180        reality = dir(src.person.Person)
181        my_expectation = [

    213        ]
214        assert reality == my_expectation
215        self.assertEqual(reality, my_expectation)
216
217
218def test_dir_person_instance():

  • I add a git commit message in the other terminal

    git commit -am
'move test_dir_person_class to TestPerson'

test_dir_person_instance with unittest

RED: make it fail

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

  • I move test_dir_person_instance to make it a method of the TestPerson class

    213        assert reality == my_expectation
214        self.assertEqual(reality, my_expectation)
215
216    def test_dir_person_instance():
217        an_instance_of_person = src.person.Person(
218            first_name='first_name',
219            last_name='last_name',
220            sex='M',
221            year_of_birth=2026,
222        )
223
224        reality = dir(an_instance_of_person)
225        my_expectation = [

    260        ]
261        assert reality == my_expectation
262
263
264# Exceptions seen

    the terminal is my friend, and shows TypeError

    TypeError:
    TestPerson.test_dir_person_instance()
    takes 0 positional arguments but 1 was given

    because …

GREEN: make it pass

I add self to the parentheses of test_dir_person_instance

213        assert reality == my_expectation
214        self.assertEqual(reality, my_expectation)
215
216    # def test_dir_person_instance():
217    def test_dir_person_instance(self):

the test is green again.

REFACTOR: make it better

  • I add a call to the assertNotEqual method in test_dir_person_instance

    262        assert reality == my_expectation
263        self.assertNotEqual(reality, my_expectation)
264
265
266# Exceptions seen

    the terminal is my friend, and shows AssertionError.

  • I change assertNotEqual to assertEqual in test_dir_person_instance

    262        assert reality == my_expectation
263        # self.assertNotEqual(reality, my_expectation)
264        self.assertEqual(reality, my_expectation)
265
266
267# Exceptions seen

    the test passes.

  • I remove the commented lines from test_dir_person_instance

    214        self.assertEqual(reality, my_expectation)
215
216    def test_dir_person_instance(self):
217        an_instance_of_person = src.person.Person(
218            first_name='first_name',
219            last_name='last_name',
220            sex='M',
221            year_of_birth=2026,
222        )
223
224        reality = dir(an_instance_of_person)
225        my_expectation = [

    260        ]
261        assert reality == my_expectation
262        self.assertEqual(reality, my_expectation)
263
264
265# Exceptions seen
266# AssertionError
267# NameError
268# TypeError
269# AttributeError
270# SyntaxError

  • I add a git commit message in the other terminal

    git commit -am
'move test_dir_person_instance to TestPerson'

close the project

  • I close test_person.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 person

    cd ..

    the terminal shows

    ...\pumping_python

    I am back in the pumping_python directory.

review

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 the telephone project with the unittest library?

rate pumping python

If this has been a 7 star experience for you, please CLICK HERE to leave a 5 star review of pumping python. It helps other people get into the book too.

CLICK HERE to leave a 5 star review of pumping python, if this has been a 7 star experience for you