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Unit-test a repository with a hand-written fake data source. Use when asked to "test a repository", "add repository tests", or to verify a [Verb][Name]Repository maps RemoteResult into DataResult correctly.
Codex または Claude でインストール この Prompt をコピーして Codex、Claude、または他のアシスタントに貼り付けると、Skill ページを確認してインストールできます。
SOC 職業分類に基づく
Add a screen's composables to a feature module using the Route → Screen → Content structure. Use when asked to "add a screen", "build the <X> screen", "wire up a screen's UI", or to render a feature's state. Pairs with add-viewmodel.
Add a ViewModel to a feature module using the Action / State / Event triad, depending on use case / repository interfaces. Use when asked to "add a viewmodel" or to wire a screen's state, actions, and events. The screen's composables are a separate skill (add-screen).
Add a reusable design-system Composable to the :ui module — stateless, themed via RickAndMortyTheme tokens, with a preview. Use when asked to "add a button", "add a shared component", "add a card/loader/empty state", or to build any reusable UI primitive shared across screens.
Unit-test a use case with hand-written fake repositories. Use when asked to "test a use case", "add use case tests", or to verify a use case's aggregation and error-propagation logic.
Unit-test a ViewModel's Action → State → Event behaviour with fakes. Use when asked to "test a viewmodel", "add viewmodel tests", or to verify a screen's state transitions and one-time events.
Add a repository to :data:core as composable single-unit repositories ([Verb][Name]Repository) encapsulated by a parent contract, each mapping a data source's RemoteResult into DataResult. Use when asked to "add a repository", "wire up a repository", or to expose data-layer operations to domain/presentation.
| name | add-repository-test |
| description | Unit-test a repository with a hand-written fake data source. Use when asked to "test a repository", "add repository tests", or to verify a [Verb][Name]Repository maps RemoteResult into DataResult correctly. |
A single-unit repository takes a data source, so a test hands it a fake that
returns canned RemoteResult — no network, no MockEngine, no Koin. We write
fakes by hand (not a mocking framework) so tests stay clear and refactor-proof.
:data:core needs kotlinx-coroutines-test (for runTest); JUnit comes from
the library convention plugin. Add via add-dependency if missing.
The data source's parent contract is public and its children are
fun interfaces — so a fake just exposes them as overridable vals with safe
defaults, and a test stubs only the one it needs:
class FakeCharacterRemoteDatasource(
override val getCharacter: GetCharacterRemoteDatasource =
GetCharacterRemoteDatasource { RemoteResult.Error("not stubbed") },
override val getCharacters: GetCharactersRemoteDatasource =
GetCharactersRemoteDatasource { RemoteResult.Error("not stubbed") },
) : CharacterRemoteDatasource
(The real CharacterRemoteDatasourceImpl is internal to :datasources:remote,
so a consumer module fakes the public interface instead.)
src/test/java/.../<feature>/GetCharacterRepositoryImplTest.kt. Hand the impl a
fake, invoke it, assert the RemoteResult was mapped to DataResult:
class GetCharacterRepositoryImplTest {
@Test
fun `maps a Success dto to a DataResult Success model`() = runTest {
val datasource = FakeCharacterRemoteDatasource(
getCharacter = GetCharacterRemoteDatasource { RemoteResult.Success(CharacterDto(id = 1, name = "Rick")) },
)
val getCharacter = GetCharacterRepositoryImpl(datasource)
val result = getCharacter(1)
assertTrue(result is DataResult.Success)
assertEquals("Rick", (result as DataResult.Success).data.name)
}
@Test
fun `maps an Error through to a DataResult Error`() = runTest {
val datasource = FakeCharacterRemoteDatasource(
getCharacter = GetCharacterRemoteDatasource { RemoteResult.Error("boom") },
)
val getCharacter = GetCharacterRepositoryImpl(datasource)
assertTrue(getCharacter(1) is DataResult.Error)
}
}
The parent repository is just a holder, and each child is a fun interface — so
fake them with lambdas, no data source at all:
val repository = CharacterRepositoryImpl(
getCharacter = GetCharacterRepository { DataResult.Success(character) },
getCharacters = GetCharactersRepository { DataResult.Success(characters) },
)
// assert it delegates: repository.getCharacter(1) === the faked result
./gradlew :data:core:testDebugUnitTest --console=plain
(Set JAVA_HOME to a JDK 21 — e.g. an SDKMAN *-jbr — if the shell can't find
Java.)
fun interface lambdas with safe defaults.:data:core:testDebugUnitTest passes.