Agile Testing: A Practical Guide for Testers and Agile Teams

You can see that we’ve labeled both quadrants that support the team (Q1 and Q2) as using automation. In Quadrant 4, the tools used for critiquing the product from a technology point of view also usually require automated tools. In Chapter 9, “Toolkit for Business-Facing Tests that Support the Team,” we discussed some of the tools that can be used for automating business-facing tests in the quest for supporting the team. In fact, the only quadrant that is not labeled as using automation is Quadrant 3—the business-facing tests that critique the product. However, as we discussed in Chapter 10, “Business-Facing Tests that Critique the Product,” tools may be useful for some of that testing. For example, automation can help set up test data and user scenarios, and analyze logged activity.

Use the quadrants to help you identify the different types of automation tools you might need for each project, even for each iteration. We find it helpful to go through each quadrant and make a checklist of what tools might be needed. Let’s say we’re about to redesign a UI. We look at Quadrant 1. How can it be coded test-first? Do we know how to unit test our presentation layer? Do we need a new tool to help with that? Now on to Quadrant 2. We’ll need to do some prototyping; should we just use paper, or should we plan a Wizard of Oz type activity? What tool will we use to create executable business-facing tests to guide development? Do we have regression test scripts that will need updating or replacing? We know that one of our Quadrant 3 activities will be usability testing. That takes some advance planning. We might want tools to help track the users’ activities so we can analyze them further. Thinking about Quadrant 4, we realize that we have load test scripts that use the old UI, so we have to budget time to update them for the new one.

See Chapter 8, “Business-Facing Tests that Support the Team,” for more about Wizard of Oz testing.

As we emphasized in Part III, “Using the Agile Testing Quadrants,” the order of quadrants doesn’t relate to the order in which we do the testing. As we make our checklist of tools needed for each type of test, we think about when we want to test so we know when to have our automation tools ready. For example, a team designing a new architecture would plan to do a spike and run scalability test against it as soon as possible. They will need to spend time during the first iteration of the project finding and implementing a performance test tool.

The quadrants help us figure out what tools we might need, but with so many different automation options at different levels, a strategy for where to do which types of testing and how to organize the tests is essential. To deliver value quickly and often, our automation efforts need a high ROI. The test pyramid helps us optimize our test investment.

Test Automation Pyramid

Figure 14-2 illustrates the “Test automation pyramid.” We like the version that Mike Cohn introduced, which shows the foundation layer made up of technology-facing unit and component tests. We recognize that many teams will struggle with this idea, because it seems the opposite of what many teams currently have. Many test teams have been taught the “V” model of testing, where activities such as component, system, and release testing are done in sequence after coding activities. Other teams have an inverted pyramid, with the majority of the tests in the functional or presentation layer.

Figure 14-2 Test automation pyramid

The agile test automation pyramid shows three different layers of automated tests. The lowest tier is the foundation that supports all of the rest. It’s mainly made up of robust unit tests and component tests, the technology-facing tests that support the team. This layer represents the bulk of the automated tests. They’re generally written in the same language as the system under test, using the xUnit family of tools. After a team has mastered the art of TDD, these tests are by far the quickest and least expensive to write. They provide the quickest feedback, too, making them highly valuable. They have the biggest ROI by far of any type of test.

In agile development, we try to push as many tests as possible to this layer. While business-facing tests tend to go in one of the higher levels, we implement them at the unit level when it makes sense. If they’re tests the customers don’t have to be able to read, and they can be coded much more quickly as unit tests, it’s a good option. Other types of technology-facing tests such as performance tests may also be possible at the unit level.

See Chapter 7, “Technology-Facing Tests that Support the Team” for more about unit and component tests.