How to prevent pytest from printing local variables during a test

Question

I'm executing a simple testing script with pytest. I'm testing if the creation of a database connection succeeded. The function that creates the database connection requires a username and a password. During the testing, pytest prints out the username and password. Obviously, I don't want passwords to be printed out to the console! How can I prevent this from happening?

I've tried multiple solutions, including using contextlib and custom created NullWriters that suppress stderr and/or stdout (for example here https://stackoverflow.com/a/1810086). However, none of it seems to have any effect.

This is the test function:

def test_make_db2_connection():

    # get username and password from the environmental variables
    username = os.environ['username']
    password = 'my_password' # would be: os.environ['pwd']

    # create a connection with the database
    connection = make_db2_connection(username, password)

    # assert if the connection exists
    assert connection, "Connection wasn't created." 

See pytest's output below. As you can see, my username and (testing) password are printed. This is what I want to prevent.

============================================================================================================ FAILURES ============================================================================================================
____________________________________________________________________________________________________ test_make_db2_connection ____________________________________________________________________________________________________

    def test_make_db2_connection():

        # get username and password from the environmental variables
        username = os.environ['username']
        password = 'my_password' # would be: os.environ['pwd']

        # create a connection with the database
>       connection = make_db2_connection(username, password)

test_file.py:16:
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

username = 'E001703', password = 'my_password'

    def make_db2_connection(username, password):
        """Creates a connection with the database"""

        dbalias = os.environ['dbalias']
>       connection = connect(dbalias, username, password)
 SQLCODE=-30082on: [IBM][CLI Driver] SQL30082N  Security processing failed with reason "24" ("USERNAME AND/OR PASSWORD INVALID").  SQLSTATE=08001

=================================================================================================== 1 failed in 14.19 seconds ====================================================================================================

Answer 1

Solved by @hoefling! See the comments below the original question.

Solution was to use __tracebackhide__ = True. Downside of this solution is that you need to modify the original function that is being tested, instead of the testing script itself.