Test-Driven Development with Python, 2nd Edition

Chapter 3. Testing a Simple Home Page with Unit Tests

We finished the last chapter with a functional test failing, telling us that it wanted the home page for our site to have “To-Do” in its title. It’s time to start working on our application.

Warning: Things Are About to Get Real

The first two chapters were intentionally nice and light. From now on, we get into some more meaty coding. Here’s a prediction: at some point, things are going to go wrong. You’re going to see different results from what I say you should see. This is a Good Thing, because it will be a genuine character-building Learning Experience™.

One possibility is that I’ve given some ambiguous explanations, and you’ve done something different from what I intended. Step back and have a think about what we’re trying to achieve at this point in the book. Which file are we editing, what do we want the user to be able to do, what are we testing and why? It may be that you’ve edited the wrong file or function, or are running the wrong tests. I reckon you’ll learn more about TDD from these “stop and think” moments than you do from all the times when following instructions and copy-pasting goes smoothly.

Or it may be a real bug. Be tenacious, read the error message carefully (see “Reading Tracebacks” a little later on in the chapter), and you’ll get to the bottom of it. It’s probably just a missing comma, or trailing slash, or maybe a missing s in one of the Selenium find methods. But, ...