Agile Testing: A Practical Guide for Testers and Agile Teams

At this point in the iteration, coding and testing continue hand in hand. Testers, programmers, database experts, and other team members collaborate to develop the stories, following the guidelines provided by examples and tests. Different team members may contribute their particular expertise, but all of them feel responsible for making sure each story is finished. All of them learn about the story and learn from each other as work progresses.

Let’s look at how a team might work on the shipping cost story in Figure 18-1. Patty Programmer picks up a task card to code the estimated shipping cost calculations. She already understands the story pretty well from earlier discussions, but she may look at the wiki pages or back of the story card where the testers wrote down some narrative describing the purpose of the story, some examples of how it should work, and some high-level tests to make sure she has a good idea of where to start. Tammy Tester sees that coding work has begun and starts to write behind-the-GUI test cases for the cost calculations.

The team had agreed during planning to start by calculating the 5-day shipping cost based on the shipping address and item weight. Items can only be shipped within continental North America, but that validation will be done in the presentation layer, so the cost calculation tests can assume only valid destinations are considered for input. They’re using a cost calculation API provided by the shipping partner, and Tammy asks Patty where to find the algorithms so she can figure the cost herself in order to write the tests. Tammy writes the simplest test case she can think of in their behind-the-GUI test tool. We show it as a simple table in Figure 18-3.

Table 18-3 Simple happy path test

Patty hasn’t finished the code that would make this test pass yet, so Tammy starts working on another testing task for the story, setting up the test environment to work with the shipping partner’s test system.

Identify Variations

Because this story and the test are so straightforward, Patty and Tammy don’t discuss the test design and tweak it as they might on more complex stories. They also haven’t needed to ask the product owner more questions yet. Patty calls Tammy over to show her that the simple test is now working. Tammy writes up more test cases, trying different weights and destinations within the United States. Those all work fine. She tries a Canadian postal code, and the test gets an exception. She shows this to Patty, who realizes that the API defaults to U.S. postal codes, and requires a country code for codes in Canada and Mexico. She hadn’t written any unit tests yet for other countries. They revise the test inputs, and Patty pairs with Paul Programmer to change the code that calls the API. Now the test looks something like Figure 18-4.

Table 18-4 Revised happy path test

This simple example illustrates the iterative back-and-forth between coding and testing. Different teams take different approaches. Patty and Tammy might pair on both the coding and testing. Tammy might pair with Paul to write the fixture to automate the test. Tammy might be in a remote office, using an online collaboration tool to work with Patty. Patty might write the executable story tests herself and then write the code to make them work, practicing true story test-driven development. The point is that testing and coding are part of one development process in which all team members participate.

Tammy can continue to identify new test cases, including edge cases and boundary conditions, until she feels all risk areas have been covered by the minimum amount and variety of test cases. She might test with the heaviest item available on the website sent to the most expensive destination. She might test having a large quantity of the same item. Some edge cases may be so unlikely that she doesn’t bother with them, or she decides to run a test but after it passes doesn’t include it in the regression suite. Some tests might be better done manually after a UI is available.

Power of Three

Patty has written unit tests with Hawaii as the shipping destination, but Tammy believes that only continental destinations are acceptable. Neither of them is sure whether military post office box destinations are acceptable. They go see Polly Product-Owner to ask what she thinks. They’re using the Power of Three. When disagreements or questions arise, having three different viewpoints is an effective way to make sure you get a good solution and you won’t have to rehash the issue later. If one of the participants in the discussion isn’t familiar with the topic, the others will have to organize their thoughts to explain it clearly, which is always helpful. Involving people in different roles helps make sure that changes to requirements don’t fly under the radar and surprise team members later.