From c9d6b8462d01ccab929e5e8d05972e9d85e561ad Mon Sep 17 00:00:00 2001
From: Hiram Chirino <hiram@hiramchirino.com>
Date: Wed, 7 Mar 2012 13:16:02 -0500
Subject: [PATCH] KT-1530 :  stdlib should include assert and require functions
 to simplify precondition checking

---
 libraries/stdlib/src/Preconditions.kt       | 48 ++++++++++++++++++++
 libraries/testlib/test/PreconditionsTest.kt | 49 +++++++++++++++++++++
 2 files changed, 97 insertions(+)
 create mode 100644 libraries/stdlib/src/Preconditions.kt
 create mode 100644 libraries/testlib/test/PreconditionsTest.kt

diff --git a/libraries/stdlib/src/Preconditions.kt b/libraries/stdlib/src/Preconditions.kt
new file mode 100644
index 00000000000..061a095332c
--- /dev/null
+++ b/libraries/stdlib/src/Preconditions.kt
@@ -0,0 +1,48 @@
+package kotlin
+
+object Assertions {
+    // TODO make private once KT-1528 is fixed.
+    val _ENABLED = (javaClass<java.lang.System>()).desiredAssertionStatus()
+}
+
+/**
+ * Throws an [[AssertionError]] if the `value` is false and runtime assertions have been
+ * enabled on the JVM using the `-ea` JVM option.
+ */
+inline fun assert(value:Boolean):Unit {
+    if(Assertions._ENABLED) {
+        if(!value) {
+            throw AssertionError();
+        }
+    }
+}
+
+/**
+* Throws an [[AssertionError]] with specified `message` if the `value` is false
+* and runtime assertions have been enabled on the JVM using the `-ea` JVM option.
+*/
+inline fun assert<T>(value:Boolean, message:T) {
+    if(Assertions._ENABLED) {
+        if(!value) {
+            throw AssertionError(message);
+        }
+    }
+}
+
+/**
+ * Throws an [[IllegalArgumentException]] if the `value` is false.
+ */
+inline fun require(value:Boolean):Unit {
+    if(!value) {
+        throw IllegalArgumentException();
+    }
+}
+
+/**
+* Throws an [[IllegalArgumentException]] with specified `message` if the `value` is false.
+*/
+inline fun require<T>(value:Boolean, message:T) {
+    if(!value) {
+        throw IllegalArgumentException(message.toString());
+    }
+}
diff --git a/libraries/testlib/test/PreconditionsTest.kt b/libraries/testlib/test/PreconditionsTest.kt
new file mode 100644
index 00000000000..278108c8cbd
--- /dev/null
+++ b/libraries/testlib/test/PreconditionsTest.kt
@@ -0,0 +1,49 @@
+package test.collections
+
+import junit.framework.TestCase
+import kotlin.test.*
+import java.lang.IllegalArgumentException
+
+class PreconditionsTest() : TestCase() {
+
+    fun testPassingRequire() {
+        require(true)
+    }
+
+    fun testFailingRequire() {
+        val error = fails {
+            require(false)
+        }
+        if(error is IllegalArgumentException) {
+            assertNull(error.getMessage())
+        } else {
+            fail("Invalid exception type: "+error)
+        }
+    }
+
+    fun testPassingRequireWithMessage() {
+        require(true, "Hello")
+    }
+
+    fun testFailingRequireWithMessage() {
+        val error = fails {
+            require(false, "Hello")
+        }
+        if(error is IllegalArgumentException) {
+            assertEquals("Hello", error.getMessage())
+        } else {
+            fail("Invalid exception type: "+error)
+        }
+    }
+
+//    // Not sure why the assert method is not being resolved.
+//    fun ignorePassingAssert() {
+//        assert(true)
+//    }
+//
+//    fun ignoreFailingAssert() {
+//        failsWith<AssertionError> {
+//            assert(false)
+//        }
+//    }
+}
\ No newline at end of file