`kotlin_jvm_test`

Host-side Kotlin tests for the Java virtual machine.

Description#

Compiles Kotlin test sources, scans the resulting classes for zero-argument test methods, and emits normalized Once test results. Methods whose names begin with test run without an external test framework. The runner also recognizes the org.junit.Test annotation from JUnit and the kotlin.test.Test annotation when their libraries are on the dependency classpath.

Test Attributes#

Attribute	Type	Required	Default	Description
`test_class`	string	no		Fully qualified class or `Class#method` filter
`args`	list<string>	no	`[]`	Additional class or `Class#method` filters
`jvm_flags`	list<string>	no	`[]`	Flags passed to the Java virtual machine before the test classpath
`env`	map<string,string>	no	`{}`	Environment variables applied before `test_env`
`env_inherit`	list<string>	no	`[]`	Host environment variable names to inherit
`test_env`	map<string,string>	no	`{}`	Environment variables applied last
`labels`	list<string>	no	`[]`	Labels exposed during test discovery
`timeout_ms`	integer	no		Optional test timeout in milliseconds
`java`	string	no	host tool	Override the Java runtime path
`javac`	string	no	host tool	Override the Java compiler used for the reflection runner

The compiler attributes from kotlin_jvm_library also apply.

Dependency Edges#

Edge	Accepts	Description
`deps`	`kotlin_jvm_library`, `java_library`	Libraries used for compilation and runtime
`associates`	`kotlin_jvm_library`	Friend modules whose internal declarations are visible during compilation
`exported_deps`	`kotlin_jvm_library`, `java_library`	Libraries propagated to compile and runtime classpaths
`provided_deps`	`kotlin_jvm_library`, `java_library`	Libraries available only while compiling
`runtime_deps`	`kotlin_jvm_library`, `java_library`	Libraries available only while running tests

Providers#

The target emits kotlin_jvm_test and once_test_info.

Capabilities#

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

Outputs#

Output	Location
Normalized results	`.once/out/<target>/test-results/test_results.json`
Test log	`.once/out/<target>/test-results/kotlin-jvm-test.log`
Native results	`.once/out/<target>/test-results/native_results.txt`

Example#

toml

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

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

[target.attrs]
labels = ["unit"]
test_class = "dev.once.greeting.GreetingTest"

Run all selected methods with once test GreetingTests. Pass a Class#method value through test_class or args for a narrower run.

Limitations#

The reflection runner does not implement test framework lifecycle hooks, parameterized tests, sharding, retries, or coverage collection. Frameworks can still supply assertions and annotations through normal dependencies.