A library for in-process compilation of Kotlin and Java code, in the spirit of Google Compile Testing. For example, you can use this library to test your annotation processor or compiler plugin.
NOTE This project is a fork of the original tschuchortdev/kotlin-compile-testing, which itself started as a fork of Moshi's compile test infra. The goal of this fork is to better track the latest Kotlin releases.
- Compile Kotlin and Java code in tests
- Test annotation processors
- Test compiler plugins
- Test Kotlin code generation
Create sources
class TestEnvClass {}
@Test
fun `test my annotation processor`() {
val kotlinSource = SourceFile.kotlin(
"KClass.kt", """
class KClass {
fun foo() {
// Classes from the test environment are visible to the compiled sources
val testEnvClass = TestEnvClass()
}
}
"""
)
val javaSource = SourceFile.java(
"JClass.java", """
public class JClass {
public void bar() {
// compiled Kotlin classes are visible to Java sources
KClass kClass = new KClass();
}
}
"""
)
}Configure compilation
val result = KotlinCompilation().apply {
sources = listOf(kotlinSource, javaSource)
// pass your own instance of an annotation processor
annotationProcessors = listOf(MyAnnotationProcessor())
// pass your own instance of a compiler plugin
compilerPlugins = listOf(MyComponentRegistrar())
commandLineProcessors = listOf(MyCommandlineProcessor())
inheritClassPath = true
messageOutputStream = System.out // see diagnostics in real time
}.compile()Assert results
assertThat(result.exitCode).isEqualTo(ExitCode.OK)
// Test diagnostic output of compiler
assertThat(result.messages).contains("My annotation processor was called")
// Load compiled classes and inspect generated code through reflection
val kClazz = result.classLoader.loadClass("KClass")
assertThat(kClazz).hasDeclaredMethods("foo")- Mixed-source sets: Compile Kotlin and Java source files in a single run
- Annotation processing:
- Run annotation processors on Kotlin and Java sources
- Generate Kotlin and Java sources
- Both Kotlin and Java sources have access to the generated sources
- Provide your own instances of annotation processors directly to the compiler instead of letting the compiler create them with a service locator
- Debug annotation processors: Since the compilation runs in the same process as your application, you can easily debug it instead of having to attach your IDE's debugger manually to the compilation process
- Inherit classpath: Compiled sources have access to classes in your application
- Project Jigsaw compatible: Kotlin-Compile-Testing works with JDK 8 as well as JDK 9 and later
- JDK-crosscompilation: Provide your own JDK to compile the code against, instead of using the host application's JDK. This allows you to easily test your code on all JDK versions
- Find dependencies automatically on the host classpath
The package is available on Maven Central.
Add dependency to your module's build.gradle file:
dependencies {
// ...
testImplementation("dev.zacsweers.kctfork:core:<version>>")
}Kotlin-Compile-Testing is compatible with all local compiler versions. It does not matter what compiler you use to compile your project.
However, if your project or any of its dependencies depend directly on compiler artifacts such as kotlin-compiler-embeddable or kotlin-annotation-processing-embeddable then they have to be the same version as the one used by Kotlin-Compile-Testing or there will be a transitive dependency conflict.
Because the internal APIs of the Kotlin compiler often change between versions, we can only support one kotlin-compiler-embeddable version at a time.
Kotlin Symbol Processing (KSP) is a new annotation processing pipeline that builds on top of the
plugin architecture of the Kotlin Compiler, instead of delegating to javac as kapt does.
To test KSP processors, you need to use the KSP dependency:
dependencies {
testImplementation("dev.zacsweers.kctfork:ksp:<version>>")
}This module adds a new function to the KotlinCompilation to specify KSP processors:<
8621
/p>
class MySymbolProcessorProvider : SymbolProcessorProvider {
// implementation of the SymbolProcessorProvider from the KSP API
}
val compilation = KotlinCompilation().apply {
sources = listOf(source)
symbolProcessorProviders = listOf(MySymbolProcessorProvider())
}
val result = compilation.compile()All code generated by the KSP processor will be written into the KotlinCompilation.kspSourcesDir directory.
With the release of Java 16 the access control of the new Jigsaw module system is starting to be enforced by the JVM. Unfortunately, this impacts kotlin-compile-testing because KAPT still tries to access classes of javac that are not exported by the jdk.compiler module, leading to errors such as:
java.lang.IllegalAccessError: class org.jetbrains.kotlin.kapt3.base.KaptContext (in unnamed module @0x43b6aa9d) cannot access class com.sun.tools.javac.util.Context (in module jdk.compiler) because module jdk.compiler does not export com.sun.tools.javac.util to unnamed module @0x43b6aa9d
To mitigate this problem, you have to add the following code to your module's build.gradle file:
if (JavaVersion.current() >= JavaVersion.VERSION_16) {
test {
jvmArgs(
"--add-opens=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
)
}
}or for Kotlin DSL
if (JavaVersion.current() >= JavaVersion.VERSION_16) {
tasks.withType<Test>().configureEach {
jvmArgs(
"--add-opens=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.code=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.comp=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.file=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.jvm=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.main=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.parser=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.processing=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.tree=ALL-UNNAMED",
"--add-opens=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED",
)
}
}Since the kotlin compilation tests run in the same process as the test runner, these options have to be added manually and can not be set automatically by the kotlin-compile-testing library.
Copyright (C) 2021 Thilo Schuchort
Licensed under the Mozilla Public License 2.0
For custom license agreements contact me directly