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Testing

Test code is located in the test/ folder:

├─ src/            # production code
├─ test/           # test code
│  ├─ MainTest.kt
│  ╰─ ...
├─ testResources/  # test resources
╰─ module.yaml

Resources that should only be available to test code go into the testResources/ folder. In multiplatform modules, platform-specific test resources can be placed in testResources@platform/ folders, just like src@platform/ folders for sources.

By default, the Kotlin test framework is preconfigured for each platform.

JUnit version

On the JVM and Android platforms, tests run with JUnit, and JUnit 5 is used by default. You can change this with the settings.junit setting, which accepts junit-5, junit-4, or none. This setting also selects which flavor of the Kotlin test library is added automatically: kotlin-test-junit5, kotlin-test-junit, or just kotlin-test, respectively. See the settings.junit reference for more details.

Additional test-only dependencies should be added to the test-dependencies: section of your module configuration file:

module.yaml
product: jvm/app

# these dependencies are available in main and test code
dependencies:
  - io.ktor:ktor-client-core:2.2.0

# additional dependencies for test code
test-dependencies:
  - io.ktor:ktor-server-test-host:2.2.0

To add or override toolchain settings in tests, use the test-settings: section:

module.yaml
# these dependencies are available in main and test code
settings:
  kotlin:
    ...

# additional test-specific setting 
test-settings:
  kotlin:
    ...

Test settings and dependencies by default are inherited from the main configuration according to the configuration propagation rules. Example: 

├─ src/
├─ src@ios/
├─ test/           # Sees declarations from src/. Executed on all platforms.
│  ├─ MainTest.kt
│  ╰─ ...
├─ test@ios/       # Sees declarations from src/, src@ios/, and `test/`. Executed on iOS platforms only.
│  ├─ IOSTest.kt
│  ╰─ ...
╰─ module.yaml

module.yaml
product:
  type: kmp/lib
  platforms: [android, iosArm64]

# these dependencies are available in main and test code
dependencies:
  - io.ktor:ktor-client-core:2.2.0

# dependencies for test code
test-dependencies:
  - org.jetbrains.kotlin:kotlin-test:1.8.10

# these settings affect the main and test code
settings: 
  kotlin:
    languageVersion: 2.1

# these settings affect tests only
test-settings:
  kotlin:
    languageVersion: 2.2 # overrides settings.kotlin.languageVersion 2.1