Add assertSame and assertNotSame methods.

libraries/kotlin.test/common/src/main/kotlin/kotlin/test/Assertions.kt

@@ -64,6 +64,16 @@ fun <@OnlyInputTypes T> assertNotEquals(illegal: T, actual: T, message: String?
     asserter.assertNotEquals(message, illegal, actual)
 }
 
+/** Asserts that [expected] is the same instance as [actual], with an optional [message]. */
+fun <@OnlyInputTypes T> assertSame(expected: T, actual: T, message: String? = null) {
+    asserter.assertSame(message, expected, actual)
+}
+
+/** Asserts that [actual] is not the same instance as [illegal], with an optional [message]. */
+fun <@OnlyInputTypes T> assertNotSame(illegal: T, actual: T, message: String? = null) {
+    asserter.assertNotSame(message, illegal, actual)
+}
+
 /** Asserts that the [actual] value is not `null`, with an optional [message]. */
 fun <T : Any> assertNotNull(actual: T?, message: String? = null): T {
     contract { returns() implies (actual != null) }
@@ -175,6 +185,24 @@ interface Asserter {
         assertTrue({ messagePrefix(message) + "Illegal value: <$actual>." }, actual != illegal)
     }
 
+    /**
+     * Asserts that the specified values are the same instance.
+     *
+     * @param message the message to report if the assertion fails.
+     */
+    fun assertSame(message: String?, expected: Any?, actual: Any?): Unit {
+        assertTrue({ messagePrefix(message) + "Expected <$expected>, actual <$actual>." }, actual === expected)
+    }
+
+    /**
+     * Asserts that the specified values are not the same instance.
+     *
+     * @param message the message to report if the assertion fails.
+     */
+    fun assertNotSame(message: String?, illegal: Any?, actual: Any?): Unit {
+        assertTrue({ messagePrefix(message) + "Illegal value: <$actual>." }, actual !== illegal)
+    }
+
     /**
      * Asserts that the specified value is `null`.
      *

libraries/kotlin.test/common/src/test/kotlin/kotlin/test/tests/BasicAssertionsTest.kt

@@ -9,6 +9,12 @@ class BasicAssertionsTest {
         assertEquals(1, 1)
     }
 
+    @Test
+    fun testAssertSame() {
+        val instance: Any = object {}
+        assertSame(instance, instance)
+    }
+
     @Test
     fun testAssertEqualsString() {
         assertEquals("a", "a")
@@ -67,6 +73,13 @@ class BasicAssertionsTest {
         checkFailedAssertion { assertEquals(1, 2) }
     }
 
+    @Test
+    fun testAssertSameFails() {
+        val instance1: Any = object {}
+        val instance2: Any = object {}
+        checkFailedAssertion { assertEquals(instance1, instance2) }
+    }
+
     @Test
     fun testAssertTrue() {
         assertTrue(true)
@@ -107,11 +120,24 @@ class BasicAssertionsTest {
         assertNotEquals(1, 2)
     }
 
+    @Test
+    fun testAssertNotSame() {
+        val instance1: Any = object {}
+        val instance2: Any = object {}
+        assertNotEquals(instance1, instance2)
+    }
+
     @Test()
     fun testAssertNotEqualsFails() {
         checkFailedAssertion { assertNotEquals(1, 1) }
     }
 
+    @Test
+    fun testAssertNotSameFails() {
+        val instance: Any = object {}
+        checkFailedAssertion { assertNotEquals(instance, instance) }
+    }
+
     @Test
     fun testAssertNotNull() {
         assertNotNull(true)

libraries/kotlin.test/js/src/main/kotlin/kotlin/test/DefaultJsAsserter.kt

@@ -44,6 +44,18 @@ internal object DefaultJsAsserter : Asserter {
         super.assertNotEquals(message, illegal, actual)
     }
 
+    override fun assertSame(message: String?, expected: Any?, actual: Any?) {
+        e = expected
+        a = actual
+        super.assertSame(message, expected, actual)
+    }
+
+    override fun assertNotSame(message: String?, illegal: Any?, actual: Any?) {
+        e = illegal
+        a = actual
+        super.assertNotSame(message, illegal, actual)
+    }
+
     override fun assertNull(message: String?, actual: Any?) {
         a = actual
         super.assertNull(message, actual)

libraries/kotlin.test/junit/src/main/kotlin/JUnitSupport.kt

@@ -27,6 +27,14 @@ object JUnitAsserter : Asserter {
         Assert.assertNotEquals(message, illegal, actual)
     }
 
+    override fun assertSame(message : String?, expected : Any?, actual : Any?) {
+        Assert.assertSame(message, expected, actual)
+    }
+
+    override fun assertNotSame(message : String?, illegal : Any?, actual : Any?) {
+        Assert.assertNotSame(message, illegal, actual)
+    }
+
     override fun assertNotNull(message : String?, actual : Any?) {
         Assert.assertNotNull(message ?: "actual value is null", actual)
     }