Introduction To Unit Testing¶
Test Driven Development¶
Download this module:
(This is the “cigar party” problem from the codingbat site)
and this test file:
Put them in the same directory, and make that directory your working directory.
Then then try running the test file with pytest:
$ pytest test_cigar_party
What you’ve done here is the first step in what is called:
Test Driven Development.
A bunch of tests exist, but the code to make them pass does not yet exist.
The red you see in the terminal when we run our tests is a goad to us to write the code that fixes these tests.
Let’s do that next!
Test Driven development¶
Open:
test_cigar_party.py
and:
cigar_party.py
In your editor.
Now edit cigar_party.py, and each time you make a change, run teh tests again. Continue until all the tests pass.
Doing your own:¶
Pick another example from codingbat:
http://codingbat.com
Do a bit of test-driven development on it:
- run something on the web site.
- write a few tests using the examples from the site.
These tests should be in a file names test_something.py – I usually name the test file the same as the module it tests, with test_ prepended.
- then write the function, and fix it ‘till it passes the tests.
Do at least two of these to get the hang of the process.
Also – once you have the tests passing, look at your solution – is there a way it could be refactored to be cleaner? Give it a shot – you’ll know if it still works if the tests still pass!