how to make a person with variables

I want to make a contact list of people. I can use variables to represent a person, for example

First Name
Last Name (Surname)
Sex
Year of Birth

can be placed in a string (anything in quotes).

preview

I have these tests by the end of the chapter

def joe():
    return 'joe, blow, M, 1996'

def jane():
    return 'jane, doe, F, 1991'

def john():
    return 'john, smith, M, 1580'

def mary():
    return 'mary, public, F, 2000'

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

def test_john():
    assert john() == 'john, smith, M, 1580'

def test_mary():
    assert mary() == 'mary, public, F, 2000'

# Exceptions seen
# AssertionError
# NameError
# TypeError

open the project

I open a terminal
I change directory to the project
```
cd person
```
the terminal shows I am in the person folder
```
.../pumping_python/person
```
I open test_person.py
I use pytest-watcher to run the tests automatically
```
uv run pytest-watcher . --now
```
the terminal shows no tests ran.

test_joe

RED: make it fail

I remove the assertion and comments then add a new test function
```
1def test_joe():
2    assert joe() == 'joe, blow, M, 1996'
3
4
5# Exceptions seen
6# AssertionError
```
the terminal is my friend, and shows NameError
```
NameError: name 'joe' is not defined
```
because there is no definition for joe in test_person.py.

I add NameError to the list of Exceptions seen

# Exceptions seen
# AssertionError
# NameError

GREEN: make it pass

I add a variable for joe and point it to None

joe = None

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

# Exceptions seen

the terminal is my friend, and shows TypeError

TypeError: 'NoneType' object is not callable

because I called joe which points to None and I cannot call None like a function. Using substitution

joe = None # point the name to the object
joe()      # call the name
None()     # substitute the value for the name

None() raises TypeError.

I add TypeError to the list of Exceptions seen

# Exceptions seen
# AssertionError
# NameError
# TypeError

I change joe to a function

# joe = None
def joe():
    return None


def test_joe():
    assert joe() == 'joe, blow, M, 1996'


# Exceptions seen

the terminal is my friend, and shows AssertionError

AssertionError: assert None == 'joe, blow, M, 1996'

because when I call joe it returns None. Using substitution since I can treat a call to a function as the object it returns

assert joe() == 'joe, blow, M, 1996'
assert None  == 'joe, blow, M, 1996'

which raises AssertionError because None is only equal to None.

I change the return statement of joe

# joe = None
def joe():
    # return None
    return 'joe, blow, M, 1996'


def test_joe():
    assert joe() == 'joe, blow, M, 1996'


# Exceptions seen

the test passes.

REFACTOR: make it better

I remove the commented lines

def joe():
    return 'joe, blow, M, 1996'

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

# Exceptions seen

I add a git commit message in the other terminal
```
git commit -am 'add test_joe'
```
the terminal shows a summary of the changes then goes back to the command line.

test_jane

RED: make it fail

I add a test function

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

# Exceptions seen

the terminal is my friend, and shows NameError

NameError: name 'jane' is not defined

because there is no definition for jane in this file.

GREEN: make it pass

I add a variable for jane and point it to None

def joe():
    return 'joe, blow, M, 1996'

jane = None

def test_joe():

the terminal is my friend, and shows TypeError

TypeError: 'NoneType' object is not callable

because I called jane which points to None and I cannot call None like a function. Using substitution

jane = None # point the name to the object
jane()      # call the name
None()      # substitute the value for the name

None() raises TypeError.

I change jane to a function

def joe():
    return 'joe, blow, M, 1996'


# jane = None
def jane():
    return None


def test_joe():

the terminal is my friend, and shows AssertionError

AssertionError: assert None == 'jane, doe, F, 1991'

because when I call jane it returns None. Using substitution since I can treat a call to a function as the object it returns

assert jane() == 'jane, doe, F, 1991'
assert None   == 'jane, doe, F, 1991'

which raises AssertionError because None is only equal to None.

I change the return statement of jane

def joe():
    return 'joe, blow, M, 1996'


# jane = None
def jane():
    # return None
    return 'jane, doe, F, 1991'


def test_joe():

the test passes.

REFACTOR: make it better

I remove the commented lines

def joe():
    return 'joe, blow, M, 1996'

def jane():
    return 'jane, doe, F, 1991'

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

# Exceptions seen

I add a git commit message in the other terminal
```
git commit -am 'add test_jane'
```
the terminal shows a summary of the changes then goes back to the command line.

test_john

RED: make it fail

I add another test function

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

def test_john():
    assert john() == 'john, smith, M, 1580'

# Exceptions seen

the terminal is my friend, and shows NameError

NameError: name 'john' is not defined

because there is no definition for john in this file, yet.

GREEN: make it pass

I add a variable for john and point it to None

def jane():
    return 'jane, doe, F, 1991'

john = None

def test_joe():

the terminal is my friend, and shows TypeError

TypeError: 'NoneType' object is not callable

because I called john which points to None and I cannot call None like a function. Using substitution

john = None # point the name to the object
john()      # call the name
None()      # substitute the value for the name

None() raises TypeError.

I change john to a function

def joe():
    return 'joe, blow, M, 1996'


# john = None
def john():
    return None


def test_joe():

the terminal is my friend, and shows AssertionError

AssertionError: assert None == 'john, smith, M, 1580'

because when I call john it returns None. Using substitution since I can treat a call to a function as the object it returns

assert john() == 'john, smith, M, 1580'
assert None   == 'john, smith, M, 1580'

which raises AssertionError because None is only equal to None.

I change the return statement of john

def jane():
    return 'jane, doe, F, 1991'


# john = None
def john():
    # return None
    return 'john, smith, M, 1580'


def test_joe():

the test passes.

REFACTOR: make it better

I remove the commented lines

def joe():
    return 'joe, blow, M, 1996'

def jane():
    return 'jane, doe, F, 1991'

def john():
    return 'john, smith, M, 1580'

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

def test_john():
    assert john() == 'john, smith, M, 1580'

# Exceptions seen

I add a git commit message in the other terminal
```
git commit -am 'add test_john'
```
the terminal shows a summary of the changes then goes back to the command line.

test_mary

RED: make it fail

I add another test function

def test_john():
    assert john() == 'john, smith, M, 1580'

def test_mary():
    assert mary() == 'mary, public, F, 2000'

# Exceptions seen

the terminal is my friend, and shows NameError

NameError: name 'mary' is not defined

because there is no definition for mary, it is just a name.

GREEN: make it pass

I add a variable for mary and point it to None

def john():
    return 'john, smith, M, 1580'

mary = None

def test_joe():

the terminal is my friend, and shows TypeError

TypeError: 'NoneType' object is not callable

because I called mary which points to None and I cannot call None like a function. Using substitution

mary = None # point the name to the object
mary()      # call the name
None()      # substitute the value for the name

None() raises TypeError.

I change mary to a function

def john():
    return 'john, smith, M, 1580'


# mary = None
def mary():
    return None


def test_joe():

the terminal is my friend, and shows AssertionError

AssertionError: assert None == 'mary, public, F, 2000'

because when I call mary it returns None. Using substitution since I can treat a call to a function as the object it returns

assert mary() == 'mary, public, F, 2000'
assert None   == 'mary, public, F, 2000'

which raises AssertionError because None is only equal to None.

I change the return statement of mary

def john():
    return 'john, smith, M, 1580'


# mary = None
def mary():
    # return None
    return 'mary, public, F, 2000'


def test_joe():

the test passes.

REFACTOR: make it better

I remove the commented lines

def joe():
    return 'joe, blow, M, 1996'

def jane():
    return 'jane, doe, F, 1991'

def john():
    return 'john, smith, M, 1580'

def mary():
    return 'mary, public, F, 2000'

def test_joe():
    assert joe() == 'joe, blow, M, 1996'

def test_jane():
    assert jane() == 'jane, doe, F, 1991'

def test_john():
    assert john() == 'john, smith, M, 1580'

def test_mary():
    assert mary() == 'mary, public, F, 2000'

# Exceptions seen
# AssertionError
# NameError
# TypeError

I add a git commit message in the other terminal
```
git commit -am 'add test_mary'
```
the terminal shows a summary of the changes then goes back to the command line.

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

I ran tests to make functions that return strings with information for people. There are a few problems with what I have so far

I made a function for each person. What happens if I have to make 10 or 100 or 1000 people? I am not ready to make 1000 functions.
Each test is basically a repetition of the information for each person.

I want something that will take in information for a person and return a representation for the person. That way I can use one thing to make as many people as I want. I can do that with functions that take input.

code from the chapter

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

what is next?

you know:

Would you like to test functions with input?

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