`android_local_test`

Android local test target.

Description#

Compiles Android Java and Kotlin test sources, then runs them on the host Java virtual machine through Once's generic test capability. This target is for local unit tests, not device or emulator instrumentation tests.

The runner scans compiled test classes and invokes zero-argument methods whose name starts with test, or methods annotated with org.junit.Test or kotlin.test.Test. Assertion libraries such as JUnit can be added through classpath and runtime_classpath.

Attributes#

Attribute	Type	Required	Default	Description
`compile_sdk`	int	no	highest installed	Android Software Development Kit platform level used for `android.jar`
`build_tools_version`	string	no	highest installed	Android Software Development Kit build-tools version
`android_sdk`	string	no	env	Android Software Development Kit root, otherwise `ANDROID_HOME` or `ANDROID_SDK_ROOT`
`java_language_level`	string	no	`17`	Java source and target level passed to `javac`
`javac_opts`	list<string>	no	`[]`	Additional `javac` flags
`javacopts`	list<string>	no	`[]`	Bazel-compatible alias for additional `javac` flags
`kotlinc_opts`	list<string>	no	`[]`	Additional `kotlinc` flags
`classpath`	list<string>	no	`[]`	Additional Java archive files used while compiling and running tests
`runtime_classpath`	list<string>	no	`[]`	Additional Java archive files used only while running tests
`args`	list<string>	no	`[]`	Additional fully qualified class or `Class#method` filters passed to the local test runner
`jvm_flags`	list<string>	no	`[]`	Additional flags passed to the host Java virtual machine before the test classpath
`test_class`	string	no	empty	Optional fully qualified test class or `Class#method` filter
`env`	map<string,string>	no	`{}`	Bazel-compatible environment variables passed to the local test runner before `test_env` overrides
`env_inherit`	list<string>	no	`[]`	Host environment variable names inherited by the local test runner before explicit test environment values
`test_env`	map<string,string>	no	`{}`	Environment variables passed to the local test runner
`labels`	list<string>	no	`[]`	Labels exposed through `once_test_info` for test discovery
`timeout_ms`	int	no		Optional test timeout in milliseconds

Accepted but unsupported attributes: custom_package, densities, enable_data_binding, manifest, manifest_values, nocompress_extensions, plugins, resource_configuration_filters, resource_jars, resource_strip_prefix, runtime_deps, and stamp. Non-empty values under [target.attrs] fail validation. Use the runtime_deps dependency role under [target.dependencies] for runtime-only libraries.

Tool override attrs are also available for javac, java, java_home, kotlinc, kotlin_home, kotlin_stdlib, and aapt2.

Dependency Edges#

Edge	Accepts	Description
`deps`	`android_library`, `java_library`	Libraries under test. `android_library` targets also emit the `java_library` provider.
`runtime_deps`	`android_library`, `java_library`	Libraries added only to the host test runtime classpath

Providers#

The target emits android_local_test and once_test_info.

Capabilities#

Capability	Output groups
`build`	`classes`
`test`	`default`, `test_results`, `logs`

Outputs#

Output	Location
Test results	`.once/out/<target>/test/test_results.json`
Test log	`.once/out/<target>/test/android-local-test.log`
Native runner output	`.once/out/<target>/test/native_results.txt`

Limitations#

android_local_test runs on the host Java virtual machine. It does not install an application package, start an Android device, or run instrumentation tests. Tests that depend on Android framework behavior usually need a local framework adapter such as Robolectric or android_instrumentation_test.

Example#

toml

[[target]]
name = "Greeting"
kind = "android_library"
srcs = ["src/main/**/*.kt"]

[target.attrs]
namespace = "dev.once.greeting"
manifest = "AndroidManifest.xml"
resource_files = []

[[target]]
name = "GreetingTests"
kind = "android_local_test"
srcs = ["src/test/**/*.kt"]
deps = ["./Greeting"]

[target.dependencies]
runtime_deps = ["./TestRuntime"]

[target.attrs]
labels = ["unit"]