monkeypatch.setenv in PyTest - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set an environment variable using monkeypatch.

PyTest

def test_env_var(monkeypatch):
    monkeypatch.[1]('MY_VAR', '123')
    import os
    assert os.getenv('MY_VAR') == '123'

Drag options to blanks, or click blank then click option'

Aset_env

Bsetenv_var

Csetenv

Dset_environment

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names like set_env or set_environment.

Trying to set environment variables without monkeypatch.

The correct method to set an environment variable with monkeypatch is setenv.

2fill in blank

medium

Complete the code to check that the environment variable is changed inside the test.

PyTest

def test_change_env(monkeypatch):
    monkeypatch.setenv('PATH', '/tmp')
    import os
    assert os.getenv('PATH') == [1]

Drag options to blanks, or click blank then click option'

A'/tmp'

B'/var/log'

C'/home/user'

D'/usr/bin'

Attempts:

3 left

💡 Hint

Common Mistakes

Expecting the original PATH value instead of the patched one.

Using incorrect string quotes.

After monkeypatch.setenv changes PATH to '/tmp', os.getenv('PATH') returns '/tmp'.

3fill in blank

hard

Fix the error in the code to correctly set the environment variable using monkeypatch.

PyTest

def test_fix_env(monkeypatch):
    monkeypatch.[1]('DEBUG', 'True')
    import os
    assert os.getenv('DEBUG') == 'True'

Drag options to blanks, or click blank then click option'

Asetenv_var

Bset_env_var

Cset_environment

Dsetenv

Attempts:

3 left

💡 Hint

Common Mistakes

Using incorrect method names that cause AttributeError.

Forgetting to import monkeypatch fixture.

The correct method is monkeypatch.setenv, not set_env_var or others.

4fill in blank

hard

Fill both blanks to set and then delete an environment variable using monkeypatch.

PyTest

def test_set_and_delete(monkeypatch):
    monkeypatch.[1]('TEMP_VAR', 'value')
    monkeypatch.[2]('TEMP_VAR', raising=False)
    import os
    assert os.getenv('TEMP_VAR') is None

Drag options to blanks, or click blank then click option'

Asetenv

Bdelenv

Cunsetenv

Dremoveenv

Attempts:

3 left

💡 Hint

Common Mistakes

Using unsetenv or removeenv which are not monkeypatch methods.

Not passing raising=False to delenv to avoid errors if variable missing.

Use monkeypatch.setenv to set and monkeypatch.delenv to delete environment variables.

5fill in blank

hard

Fill all three blanks to set an environment variable, check its value, and then delete it using monkeypatch.

PyTest

def test_full_env(monkeypatch):
    monkeypatch.[1]('API_KEY', 'abc123')
    import os
    assert os.getenv([2]) == 'abc123'
    monkeypatch.[3]('API_KEY', raising=False)
    assert os.getenv('API_KEY') is None

Drag options to blanks, or click blank then click option'

Asetenv

B'API_KEY'

Cdelenv

D'api_key'

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong case for environment variable name.

Forgetting to delete the variable after test.

Use setenv to set, the exact string 'API_KEY' to check, and delenv to delete the variable.

Practice

1.

What is the main purpose of monkeypatch.setenv in pytest?

easy

A. Create new environment variables outside tests

B. Permanently change environment variables on the system

C. Temporarily change environment variables during a test

D. Delete environment variables permanently

Solution

1. Step 1: Understand the role of monkeypatch in pytest

   Monkeypatch is used to temporarily modify or replace parts of the environment during tests without permanent effects.

2. Step 2: Focus on setenv method

   The setenv method specifically changes environment variables only for the duration of the test.

3. Final Answer:

   Temporarily change environment variables during a test -> Option C

4. Quick Check:

   monkeypatch.setenv = temporary env change [OK]

Hint: Remember: monkeypatch.setenv only affects test-time env variables [OK]

Common Mistakes:

• Thinking setenv changes env variables permanently
• Confusing setenv with creating new system variables
• Assuming changes persist after test ends

2.

Which of the following is the correct syntax to set an environment variable API_KEY to 12345 using monkeypatch.setenv in a pytest test function?

def test_api_key(monkeypatch):
    # Your code here
    assert ...

easy

A. monkeypatch.setenv('API_KEY', '12345')

B. monkeypatch.setenv('API_KEY', 12345)

C. monkeypatch.setenv(API_KEY='12345')

D. monkeypatch.setenv('API_KEY') = '12345'

Solution

1. Step 1: Check method signature of setenv

   setenv takes two string arguments: the variable name and its value.

2. Step 2: Identify correct string usage

   The value must be a string, so '12345' is correct, not integer 12345.

3. Final Answer:

   monkeypatch.setenv('API_KEY', '12345') -> Option A

4. Quick Check:

   setenv('VAR', 'value') syntax [OK]

Hint: Always pass env var values as strings in setenv [OK]

Common Mistakes:

• Passing integer instead of string as value
• Using keyword arguments instead of positional
• Trying to assign value with '=' outside method call

3.

What will be the output of the following pytest test?

import os

def test_env(monkeypatch):
    monkeypatch.setenv('MODE', 'test')
    mode = os.getenv('MODE')
    assert mode == 'test'
    print(mode)

medium

A. AssertionError

B. None

C. MODE

D. test

Solution

1. Step 1: Understand monkeypatch.setenv effect

   It sets environment variable 'MODE' to 'test' temporarily during the test.

2. Step 2: Check os.getenv call and assertion

   os.getenv('MODE') returns 'test', so assertion passes and print outputs 'test'.

3. Final Answer:

   test -> Option D

4. Quick Check:

   setenv sets env var, getenv reads it [OK]

Hint: setenv changes env var for test, getenv reads it [OK]

Common Mistakes:

• Expecting None because env var not set globally
• Thinking assertion fails
• Confusing variable name with value

4.

Identify the error in this pytest test using monkeypatch.setenv:

def test_path(monkeypatch):
    monkeypatch.setenv(PATH)
    assert os.getenv('PATH') == '/usr/bin'

medium

A. Missing import of os module

B. setenv missing value argument

C. Incorrect assertion syntax

D. Using monkeypatch outside test function

Solution

1. Step 1: Check setenv method call

   setenv requires two arguments: variable name and value. Here only one argument is given.

2. Step 2: Verify assertion and imports

   Assertion syntax is correct and os module import is assumed; error is in setenv call.

3. Final Answer:

   setenv missing value argument -> Option B

4. Quick Check:

   setenv needs two args: name and value [OK]

Hint: setenv always needs two strings: var name and value [OK]

Common Mistakes:

• Calling setenv with only one argument
• Forgetting to import os module
• Miswriting assertion statement

5.

You want to test a function that behaves differently based on the environment variable FEATURE_FLAG. Which pytest test code correctly uses monkeypatch.setenv to test the function with FEATURE_FLAG set to enabled and ensures the environment is restored after the test?

def test_feature(monkeypatch):
    # Your code here
    result = feature_function()
    assert result == 'Feature Enabled'

hard

A. monkeypatch.setenv('FEATURE_FLAG', 'enabled')

B. os.environ['FEATURE_FLAG'] = 'enabled'

C. monkeypatch.setenv(FEATURE_FLAG='enabled')

D. monkeypatch.setenv('FEATURE_FLAG') = 'enabled'

Solution

1. Step 1: Identify correct usage of monkeypatch.setenv

   setenv requires two string arguments: variable name and value, passed positionally.

2. Step 2: Understand environment restoration

   Using monkeypatch.setenv ensures the env var is set only during the test and restored after, unlike direct os.environ assignment.

3. Final Answer:

   monkeypatch.setenv('FEATURE_FLAG', 'enabled') -> Option A

4. Quick Check:

   Use monkeypatch.setenv for temporary env changes [OK]

Hint: Use monkeypatch.setenv for temp env vars, not os.environ [OK]

Common Mistakes:

• Directly modifying os.environ without monkeypatch
• Using keyword arguments in setenv
• Trying to assign value outside setenv call