Flutter and Dart Cookbook

Chapter 6. Dart Test Cases

In this chapter, you will learn how to create test cases for your Dart-based code. Testing is a valuable stage of development that provides a link between application requirements and developed code. Testing is an important step in every developer’s workflow. Ensuring that an application’s behavior is aligned to a specification can significantly reduce the amount of effort to track defects. Defining guardrails for how an application should behave gives the developer confidence when making enhancements, as they are able to quickly identify whether a change breaks existing functionality.

Dart and Flutter share a test framework, so over the course of this chapter I begin the discussion on testing and its relevance to creating applications in Dart. Generally, Dart/Flutter testing can be broken down into three distinct types: unit, integration, and widget UI, as shown in Figure 6-1.

Figure 6-1. The test pyramid

In this chapter, we will cover the unit and integration aspects, which are the first two types of testing, as illustrated in Figure 6-1. The most common type of testing, from a developer perspective, is unit testing. A unit test compares an input to an individual function/class with the expected output. Such tests are run against the developed code and will typically report back as a pass/fail for the scenario presented.

The combination of unit ...