JarCasting
⌨️
kotlin-test-factories
Auto-generated test factory functions for Kotlin. Works with KAPT by dynamically creating source files.
- Build the project (hit
CMD+F9orCtrl+F9). IntelliJ has to be configured to build with Gradle. - Invoke the
kaptTestgradle task.
🤷♀️
Why?
How to write a test for the name method?
data class User(
val firstName: String,
val lastName: String,
val address: Address
) {
fun name(): String = "$firstName $lastName"
}
The code below looks clean...
@Test
fun name() {
val user = User(
firstName = "John",
lastName = "Smith"
)
assertThat(user.name()).isEqualTo("John Smith")
}
...but it doesn't compile: the address constructor parameter isn't provided. Specifying a random address would make the compiler happy at the cost of developer happiness. It would only introduce noise to a perfectly fine test.
A good test should be readable, focused and define clear inputs. And so is this one.
As a workaround one can write a test factory function:
fun aUser(
firstName: String = "",
lastName: String = "",
address: Address = anAddress()
): User {
return User(
firstName = firstName,
lastName = lastName,
address = address
)
}
With a test factory User instances can be obtained by specifying relevant fields and omitting irrelevant ones. Our final test looks like this:
@Test
fun name() {
val user = aUser(
firstName = "John",
lastName = "Smith"
)
assertThat(user.name()).isEqualTo("John Smith")
}
Job done! Here is a bummer though: writing and maintaining test factories is laborious and more boring than scraping the internet for thousands of food pictures. This library generates test factories automatically.
🏗
Usage
Add to build.gradle.kts:
plugins {
kotlin("jvm") version "1.4.21"
kotlin("kapt") version "1.4.21"
}
dependencies {
testImplementation("pl.rzrz:kotlin-test-factories-core:VERSION") // annotations + support for generated factories
kaptTest("pl.rzrz:kotlin-test-factories-generator:VERSION") // generator
}
Create a configuration in test sources:
package com.me
@TestFactoriesConfig([
User::class
])
interface TestFactoriesConfiguration
Write tests:
import com.me.TestFactories.aUser
class UserTest {
@Test
fun name() {
val user = aUser(
firstName = "John",
lastName = "Smith"
)
assertThat(user.name()).isEqualTo("John Smith")
}
}
📃
Features
- Generate test factories
- Default package same as config
- Customizable package and class name
- Support for generic types
- Support for recursive types