Version 2.0.0-rc2

build.gradle.kts

@@ -5,7 +5,7 @@ plugins {
 
 allprojects {
     group = "dev.minutest"
-    version = "2.0.0-rc1"
+    version = "2.0.0-rc2"
 
     repositories {
         mavenCentral()

core/src/main/kotlin/dev/minutest/experimental/mutation.kt

@@ -0,0 +1,47 @@
+package dev.minutest.experimental
+
+import dev.minutest.combinedWith
+import dev.minutest.internal.duplicatorFor
+import kotlin.reflect.KProperty1
+
+typealias Mutation<T> = (T) -> T
+
+fun <T> mutation(name: String, mutation: Mutation<T>) = object : Mutation<T> by mutation {
+    override fun toString() = name
+}
+
+fun <T, V> mutation(name: String, value: V, mutation: Mutation<T>) =
+    mutation("$name = $value", mutation)
+
+infix fun <T> Mutation<T>.andThen(another: Mutation<T>): Mutation<T> =
+    mutation("($this) and ($another)") {
+        another(this(it))
+    }
+
+fun <T> Iterable<Mutation<T>>.combined(
+    other: Iterable<Mutation<T>>
+): List<Mutation<T>> = combinedWith(other).map { (a, b) -> a andThen b }
+
+fun <T : Any, V> mutation(
+    property: KProperty1<T, V>,
+    value: V
+): Mutation<T> {
+    // outside the lambda so that we don't keep doing the reflective lookups
+    val duplicator = duplicatorFor(property)
+    return mutation(property.name, value) {
+        duplicator(it, value)
+    }
+}
+
+fun <T : Any, V> Iterable<V>.asMutationsOf(
+    property: KProperty1<T, V>
+) = map { mutation(property, it) }
+
+
+/**
+ * Something that has been mutated - the [name] says how.
+ */
+data class Mutant<T>(
+    val name: String,
+    val value: T
+)