Integration testing

Integration testing focuses on validating your component's behavior as it interacts with other components on the system. Because of this, integration tests are typically built separately from the main component and may declare the component under test and other dependencies as children. Depending on the nature of the test, dependency components may be provided as mocks or stubs to promote that the test cases remain hermetic.

Test components

Below is an example component manifest for a simple integration test component:

meta/integration_tests.cml:

{
    include: [
        "//pkg/syslog/client.shard.cml",
        "//pkg/sys/testing/elf_test_runner.shard.cml",
    ],
    program: {
        binary: "bin/client_test",
    },
    children: [
        {
            name: "service",
            url: "fuchsia-pkg://fuchsia.com/foo-package-tests#meta/mock_service.cm",
        },
        {
            name: "client",
            url: "fuchsia-pkg://fuchsia.com/foo-package-tests#meta/foo_client.cm",
        },
    ],
    offer: [
        {
            protocol: "fuchsia.example.Foo",
            from: "#service",
            to: [ "#client" ],
        },
    ],
}

This test component declaration contains the following key elements:

An include of the necessary language-specific test runner shard. This enables the test manager to properly execute the test suite.
Listing the component under test and dependent components as children.
Routing required capabilities between components in the test realm.

The Fuchsia SDK provides additional templates to facilitate the creation of integration test components:

fuchsia_cc_test(): Compiles the C++ source code into a test binary.
fuchsia_test_component(): Generates a Fuchsia component containing tests using the provided component manifest. You can combine multiple test components into the same fuchsia_test_package().

Here is an example of how the above integration test could be included in the BUILD.bazel file:

load(
    "fuchsia_cc_test",
    "fuchsia_component",
    "fuchsia_component_manifest",
    "fuchsia_test_component",
    "fuchsia_test_package",
)

# Component under test
fuchsia_component(
    name = "foo_client",
    manifest = ":foo_client_manifest",
    visibility = ["//visibility:public"],
)

# Test dependencies
fuchsia_component(
    name = "mock_service",
    manifest = ":mock_service_manifest",
    visibility = ["//visibility:public"],
)

# Component containing integration tests
fuchsia_cc_test(
    name = "client_integration_test",
    srcs = [ ... ],
    deps = [ ... ],
)
fuchsia_component_manifest(
    name = "integration_test_manifest",
    src = "meta/integration_tests.cml",
)
fuchsia_test_component(
    name = "integration_test_component",
    manifest = ":integration_test_manifest",
    test_name = "client_integration_test",
    visibility = ["//visibility:public"],
    deps = [":client_integration_test"],
)

# Hermetic test package
fuchsia_test_package(
    name = "integration_test_pkg",
    visibility = ["//visibility:public"],
    deps = [
        ":foo_client",
        ":mock_service",
        ":integration_test_component",
    ],
)

This integration test build configuration contains the following key elements:

A fuchsia_test_component() target describing the integration test component and its component manifest.
Additional fuchsia_component() targets representing component dependencies requited by the integration tests.
A single hermetic fuchsia_test_package() that bundles the test component and all dependencies together.

Exercise: Echo server integration test

In this exercise, you'll add an integration test component to exercise the FIDL protocol interface of the echo_server component with the Test Runner Framework and run those tests in a FEMU environment.

Add an integration test component

To begin, create a new project directory in your Bazel workspace:

mkdir -p fuchsia-codelab/echo-integration

After you complete this section, the project should have the following directory structure:

//fuchsia-codelab/echo-integration
                  |- BUILD.bazel
                  |- meta
                  |   |- echo_integration_test.cml
                  |
                  |- echo_integration_test.cc

Create the test component manifest

Create the echo-integration/meta/echo_integration_test.cml test component manifest to declare the echo-server component as a child and route the Echo protocol capability to the test component.

echo-integration/meta/echo_integration_test.cml:

{
    include: [
        "syslog/client.shard.cml",
        "sys/testing/elf_test_runner.shard.cml",
    ],

    // Information about the program to run.
    program: {
        // The binary to run for this component.
        binary: "bin/echo_integration_test",
    },

    // Child components orchestrated by the integration test.
    children: [
        {
            name: "echo_server",
            url: "#meta/echo_server.cm",
        },
    ],

    // Capabilities used by this component.
    use: [
        {
            protocol: [ "examples.routing.echo.Echo" ],
            from: "#echo_server",
        },
    ],

    // Capabilities required by components under test.
    offer: [
        {
            protocol: [ "fuchsia.logger.LogSink" ],
            from: "parent",
            to: "#echo_server",
        },

    ],
}

Notice that the echo-server instance comes from the same package as the integration test. This practice promotes test packages that are hermetic by avoiding dependencies on components from other packages.

Add the following rules to your BUILD.bazel file to include the integration test component in the build configuration:

echo-integration/BUILD.bazel:

load(
    "@fuchsia_sdk//fuchsia:defs.bzl",
    "fuchsia_cc_test",
    "fuchsia_component_manifest",
    "fuchsia_test_component",
    "fuchsia_test_package",
)

fuchsia_cc_test(
    name = "echo_integration_test",
    size = "small",
    srcs = ["echo_integration_test.cc"],
    deps = [
        "//fuchsia-codelab/echo-fidl:examples.routing.echo.fidl_cc",
        "@com_google_googletest//:gtest_main",
        "@fuchsia_sdk//pkg/async-default",
        "@fuchsia_sdk//pkg/async-loop",
        "@fuchsia_sdk//pkg/async-loop-cpp",
        "@fuchsia_sdk//pkg/async-loop-default",
        "@fuchsia_sdk//pkg/fdio",
        "@fuchsia_sdk//pkg/component_incoming_cpp",
        "@fuchsia_sdk//pkg/syslog",
    ],
)

fuchsia_component_manifest(
    name = "test_manifest",
    src = "meta/echo_integration_test.cml",
    component_name = "echo_integration_test_component",
    includes = [
        "@fuchsia_sdk//pkg/sys/testing:elf_test_runner",
        "@fuchsia_sdk//pkg/syslog:client",
    ],
)

fuchsia_test_component(
    name = "echo_integration_test_component",
    manifest = ":test_manifest",
    visibility = ["//visibility:public"],
    deps = [":echo_integration_test"],
)

fuchsia_test_package(
    name = "test_pkg",
    package_name = "echo_integration_test",
    visibility = ["//visibility:public"],
    components = [
        "//fuchsia-codelab/echo-server:echo_server_component",
    ],
    test_components = [
        ":echo_integration_test_component",
    ],
)

Implement the integration test

The integration test connects to the Echo protocol exposed by the echo-server in the same way as the client component, sends a string request, and validates the expected response.

Add the following code to implement an integration test:

echo-integration/echo_integration_test.cc:

#include <fidl/examples.routing.echo/cpp/fidl.h>
#include <gtest/gtest.h>
#include <lib/component/incoming/cpp/protocol.h>

#include <string>

TEST(EchoIntegrationTest, TestEcho) {
  zx::result client_end = component::Connect<examples_routing_echo::Echo>();
  ASSERT_TRUE(client_end.is_ok());
  fidl::SyncClient client{std::move(*client_end)};

  std::string request("Hello, world!");
  fidl::Result result = client->EchoString({request});
  ASSERT_TRUE(result.is_ok());

  auto response = result->response();
  ASSERT_TRUE(response.has_value());
  ASSERT_EQ(request, response.value());
}

Update the build configuration

Build and publish the integration test package to the fuchsiasamples.com repository:

bazel run //fuchsia-codelab/echo-integration:test_pkg.publish -- \
    --repo_name fuchsiasamples.com

Run the integration test

The fuchsia_test_package() rule generates a package with the test component and its dependencies. The integration test component has the following URL:

fuchsia-pkg://fuchsiasamples.com/echo_integration_test#meta/echo_integration_test.cm

Use the ffx test command to execute the integration tests. Verify that the tests pass:

ffx test run \
    fuchsia-pkg://fuchsiasamples.com/echo_integration_test#meta/echo_integration_test.cm

Connecting components

Diagnostics and monitoring