How to pass environment variables to pytest

Before I start executing the tests in my Python project, I read some environment variables and set some variables with these values read. My tests will run on the desired environment based on these values read.

For eg: Let's say the environment variables are called ENV_NAME and ENV_NUMBER

Now, I would like to run the tests using py.test.

If I hard code these environment variables, for eg: ENV_NAME = 'staging', ENV_NUMBER = '5' in my code and then run the tests by executing the py.test command at the root of the project directory, all the tests run successfully.

But, I don't want to hardcode these values. Is there a way, I can send these environment variables as command line arguments for py.test?

I was thinking more in the lines of

py.test -ENV_NAME='staging' -ENV_NUMBER='5'.

But, this is not working.

Solution 1:

Another alternative is to use the pytest-env plugin. It can be configured like so:

[pytest]
env = 
    HOME=~/tmp
    D:RUN_ENV=test

the D: prefix allows setting a default value, and not override existing variables passed to py.test.

Note: you can explicitly run pytest with a custom config, if you only sometimes need to run a specialized environment set up:

pytest -c custom_pytest.ini

If you use PyCharm vs pytest-dotenv, this may be helpful

Solution 2:

In addition to other answers. There is an option to overwrite pytest_generate_tests in conftest.py and set ENV variables there.

For example, add following into conftest.py:

import os

def pytest_generate_tests(metafunc):
    os.environ['TEST_NAME'] = 'My super test name| Python version {}'.format(python_version)

This code will allow you to grab TEST_NAME ENV variable in your tests application. Also you could make a fixture:

import os
import pytest

@pytest.fixture
def the_name():
    return os.environ.get('TEST_NAME')

Also, this ENV variable will be available in your application.

Solution 3:

I finally found the answer i was looking for.

we can set the environment variables like this before running tests using py.test

ENV_NAME='staging' ENV_NUMBER='5' py.test