Testing a class with assert

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. Account starts with balance 100. After acc.deposit(50), which line correctly checks the attribute?

A assert acc.balance = 150

B assert acc.balance == 150

2. Which assert checks the value RETURNED by a method?

A assert dog.speak() == "Woof"

B assert dog.speak == "Woof"

3. What happens when the condition in an assert is False?

A Python quietly carries on to the next line

B Python raises an AssertionError

4. Which is the right order for a simple class test?

A Create the object, call the method, then assert

B Assert first, then create the object and call the method

5. A setter ignores negative values. Pet starts with age 3, then you call pet.set_age(-5). Which test is correct?

A assert pet.age == 3

B assert pet.age == -5

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1assert account.balance == 150		AChecks that the balance attribute equals 150 after a method has run, and raises an AssertionError if it does not
2assert dog.speak() == "Woof"		Bdef test_deposit(): acc = Account(100) acc.deposit(50) assert acc.balance == 150
3Test a setter with invalid input: call it with a bad value, then assert the attribute did not change		Cplayer.set_age(-5) assert player.age == 14
4Write one test per method: create an object, call that method, then assert on the result		DA single = assigns a value and is a syntax error in an assert. Use == to compare the returned value with the expected one.
5assert car.drive(10) = 10		EThe method call car.accelerate() is missing, so the speed never changes and the assert fails. Call the method before checking the attribute.
6car.speed == 20 assert car.speed == 20		FCalls the speak() method and checks that the value it returns is exactly "Woof"

Definitions

assert obj.method() == expected

Fill in the Blanks

Complete each line of code by filling in the missing parts.

acc = Account(50) acc.deposit(20) ______ acc.balance == 70

acc = Account(50) acc._______(20) assert acc.balance == 70

acc = Account(50) acc.withdraw(20) assert acc.balance == __

acc = Account(50) acc.___________(-10) assert acc.balance == 50

acc = Account(50) acc.deposit(20) assert acc._______ == 70

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A acct = Account(50)

B acct.deposit(25)

C assert acct.balance == 75

D assert acct.get_balance() = 75

Question 2

A dog = Dog('Rex')

B assert dog.name == Rex

C dog.rename('Max')

D assert dog.name == 'Max'

Question 3

A lamp = Lamp()

B lamp.switch_on()

C assert lamp.is_on() == True

Question 4

A p = Player('Ana')

B p.set_health = -5

C assert p.health == 100

Question 5

A car = car('red', 0)

B car.drive(10)

C assert car.distance == 10

Answer Key

Testing a class with assert

Section A: Quick Questions

B — assert acc.balance == 150

A — assert dog.speak() == "Woof"

B — Python raises an AssertionError

A — Create the object, call the method, then assert

A — assert pet.age == 3

Section B: Match the Pairs

assert account.balance == 150 → Checks that the balance attribute equals 150 after a method has run, and raises an AssertionError if it does not

assert dog.speak() == "Woof" → Calls the speak() method and checks that the value it returns is exactly "Woof"

Test a setter with invalid input: call it with a bad value, then assert the attribute did not change → player.set_age(-5) assert player.age == 14

Write one test per method: create an object, call that method, then assert on the result → def test_deposit(): acc = Account(100) acc.deposit(50) assert acc.balance == 150

assert car.drive(10) = 10 → A single = assigns a value and is a syntax error in an assert. Use == to compare the returned value with the expected one.

car.speed == 20 assert car.speed == 20 → The method call car.accelerate() is missing, so the speed never changes and the assert fails. Call the method before checking the attribute.

Section C: Definitions

assert obj.method() == expected — Creates an object, calls its method, then uses assert to check the result or attribute equals what you expect. If it is False, Python raises an AssertionError.

Section D: Fill in the Blanks

acc = Account(50)
acc.deposit(20)
assert acc.balance == 70

acc = Account(50)
acc.deposit(20)
assert acc.balance == 70

acc = Account(50)
acc.withdraw(20)
assert acc.balance == 30

acc = Account(50)
acc.set_balance(-10)
assert acc.balance == 50

acc = Account(50)
acc.deposit(20)
assert acc.balance == 70

Section E: Spot the Error

D — A single = tries to assign a value, which is a SyntaxError. An assert must compare with ==, so it should be assert acct.get_balance() == 75.

B — Rex has no quotes, so Python looks for a variable called Rex and raises a NameError. The expected text must be a string: 'Rex'.

C — is_on is an attribute, not a method. Adding () tries to call a True/False value and causes a TypeError. It should be assert lamp.is_on == True.

B — This overwrites the set_health method with -5 instead of calling it, so the setter never gets the invalid input. It should be p.set_health(-5).

A — The class is named Car with a capital C. Python is case-sensitive, so car is not defined and raises a NameError. It should be car = Car('red', 0).