python-tdd-book/textbook/chap6.md

# Chapter 6. Improving Functional Tests: Ensuring Isolation and Removing Voodoo Sleeps

## 6.1 Ensuring Test Isolation in Functional Tests

* Problem left on scratchpad: Clean up after FT runs
* Methods:
  * 1. In `functional_tests.py` add in codes to delete database
  * 2. Use class `LiveServerTestCase` (Django 1.4). It will create a test db and start up a dev server for functional tests

How to use `LiveServerTestCase`:
* It's derived from Django's `TestCase` class, so can be run by Django test runner
* Django test runner search for all scripts start with `test`

What to do?:
1. Create a `functional_test` directory, i.e. create a *functional_test* app
2. rename `functional_test.py` as `tests.py` and move it into `functional_test` directory
3. Modify `tests.py` to let it use `LiveServerTestCase` as shown below, and instead of hardcoding visit to localhost port 8000, `LiveserverTestCase` provide attribute `live_server_url`.

```python
class NewVisitorTest(LiveServerTestCase):
    ...

    def test_can_start_a_list_and_retrieve_it_later(self):
        # Edith has heard about a cool new online to-do app. She goes
        # to check out its homepage
        self.browser.get(self.live_server_url)
```

### 6.1.1 Running Just the Unit Tests

We can specify what we want to run by

```
python manage.py test functional_tests
```

or

```
python manage.py test lists
```

## 6.2 Aside: Upgrading Selenium and Geckodriver

Sometimes, mismatch between firefox and (Selenium + Geckodriver) may result failure in test, as firefox may auto upgrade itself at night. Upgrade Selenium + Geckodriver as follow:

1. `pip install --upgrade selenium`
2. Download new geckodriver