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Test Components

A migration from Components v1 to v2 is in progress.


Test components are components that implement a test. Tests run in a given environment, and then report whether they passed or failed. Typically tests are written using various testing frameworks, and may report more detailed results such as whether individual test cases within a test suite passed or failed.

The Component Framework allows launching tests as components. Most tests are comprised of a single component - these are typically referred to as unit tests. Some tests exercise multiple components working together - these are typically referred to as integration tests.

Creating a test component and package

A test package may contain one or more test components. Test components are components that implement a test suite. Test packages can also contain other components that are not the test itself, but participate in the test. For instance:

  • A package may contain a single test component which implements a unit test that exercises some business logic.
  • A package may contain a test component and a second component that implements a service. The test component may then act as a client of the second component, which makes for an integration test between client and server code. Both the clients and server are located in the same package in order to ensure that the second component is present and can be launched by the test component.

In order to define your test package and components, you should use the appropriate build rules. Refer to the test packages guide.

Test component manifest

Every component has a manifest. Test components follow the same manifest syntax as any other components.

A component manifest for a simple unit test might be named meta/my_test.cml and look as follows:

    include: [
    program: {
        binary: "bin/my_test"

Component manifests for simple unit tests can be generated by the build rules.

Running your test

To run a Fuchsia test out of your build, execute:

fx test TEST_NAME

For more information, see Run Fuchsia tests.

Further reading