Add value class support to eq() argument matcher (#545)

Fixes #544

Author: m-koops

mockito-kotlin/src/main/kotlin/org/mockito/kotlin/Matchers.kt

@@ -31,7 +31,10 @@ import org.mockito.kotlin.internal.createInstance
 import kotlin.reflect.KClass
 
 /** Object argument that is equal to the given value. */
-fun <T> eq(value: T): T {
+inline fun <reified T : Any?> eq(value: T): T {
+    if(T::class.isValue)
+        return eqValueClass(value)
+
     return ArgumentMatchers.eq(value) ?: value
 }
 
@@ -80,15 +83,30 @@ inline fun <reified T > anyValueClass(): T {
         "${T::class.qualifiedName} is not a value class."
     }
 
-    val boxImpls = T::class.java.declaredMethods.filter { it.name == "box-impl" && it.parameterCount == 1 }
-    require(boxImpls.size == 1) // Sanity check
-
-    val boxImpl = boxImpls.first()
+    val boxImpl =
+        T::class.java.declaredMethods
+            .single { it.name == "box-impl" && it.parameterCount == 1 }
     val boxedType = boxImpl.parameters[0].type
 
     return boxImpl.invoke(null, ArgumentMatchers.any(boxedType)) as T
 }
 
+inline fun <reified T > eqValueClass(value: T): T {
+    require(T::class.isValue) {
+        "${T::class.qualifiedName} is not a value class."
+    }
+
+    val unboxImpl =
+        T::class.java.declaredMethods
+            .single { it.name == "unbox-impl" && it.parameterCount == 0 }
+    val unboxed = unboxImpl.invoke(value)
+
+    val boxImpl =
+        T::class.java.declaredMethods.single { it.name == "box-impl" && it.parameterCount == 1 }
+
+    return boxImpl.invoke(null, ArgumentMatchers.eq(unboxed) ?: unboxed) as T
+}
+
 /**
  * Creates a custom argument matcher.
  * `null` values will never evaluate to `true`.

tests/src/test/kotlin/test/EqTest.kt

@@ -94,6 +94,18 @@ class EqTest : TestBase() {
         expect(result).toBeNull()
     }
 
+    @Test
+    fun eqValueClassInstance() {
+        /* Given */
+        val valueClass = ValueClass("Content")
+
+        /* When */
+        val result = eq(valueClass)
+
+        /* Then */
+        expect(result).toBe(valueClass)
+    }
+
     private interface MyInterface
     private open class MyClass : MyInterface
     class ClosedClass

tests/src/test/kotlin/test/MatchersTest.kt

@@ -389,6 +389,41 @@ class MatchersTest : TestBase() {
         }
     }
 
+    @Test
+    fun eq_forValueClass() {
+        val valueClass = ValueClass("Content")
+        mock<Methods>().apply {
+            valueClass(valueClass)
+            verify(this).valueClass(eq(valueClass))
+        }
+    }
+
+    @Test
+    fun eq_withNestedValueClass() {
+        val nestedValueClass = NestedValueClass(ValueClass("Content"))
+        mock<Methods>().apply {
+            nestedValueClass(nestedValueClass)
+            verify(this).nestedValueClass(eq(nestedValueClass))
+        }
+    }
+
+    @Test
+    fun eq_withClosedClass() {
+        val closedClassInstance = Closed()
+        mock<Methods>().apply {
+            closed(closedClassInstance)
+            verify(this).closed(eq(closedClassInstance))
+        }
+    }
+
+    @Test
+    fun eq_withInt() {
+        mock<Methods>().apply {
+            int(3)
+            verify(this).int(eq(3))
+        }
+    }
+
     /**
      * a VarargMatcher implementation for varargs of type [T] that will answer with type [R] if any of the var args
      * matched. Needs to keep state between matching invocations.