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

[[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.