From 90c070cb1d90d77ba461017e609b9f8ee6326de1 Mon Sep 17 00:00:00 2001
From: Ben Wiederhake <BenWiederhake.GitHub@gmx.de>
Date: Sun, 21 Feb 2021 22:09:25 +0100
Subject: [PATCH] AK+Tests: Test Checked for main functionality

---
 AK/Tests/TestChecked.cpp | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/AK/Tests/TestChecked.cpp b/AK/Tests/TestChecked.cpp
index 20ea0032dc..85abb9e530 100644
--- a/AK/Tests/TestChecked.cpp
+++ b/AK/Tests/TestChecked.cpp
@@ -95,6 +95,29 @@ TEST_CASE(operator_arith)
     EXPECT_EQ(b / a, 28);
 }
 
+TEST_CASE(detects_signed_overflow)
+{
+    EXPECT(!(Checked<int>(0x40000000) + Checked<int>(0x3fffffff)).has_overflow());
+    EXPECT((Checked<int>(0x40000000) + Checked<int>(0x40000000)).has_overflow());
+    EXPECT(!(Checked<int>(-0x40000000) + Checked<int>(-0x40000000)).has_overflow());
+    EXPECT((Checked<int>(-0x40000001) + Checked<int>(-0x40000000)).has_overflow());
+
+    EXPECT(!(Checked<int>(0x40000000) - Checked<int>(-0x3fffffff)).has_overflow());
+    EXPECT((Checked<int>(0x40000000) - Checked<int>(-0x40000000)).has_overflow());
+    EXPECT(!(Checked<int>(-0x40000000) - Checked<int>(0x40000000)).has_overflow());
+    EXPECT((Checked<int>(-0x40000000) - Checked<int>(0x40000001)).has_overflow());
+
+    EXPECT(!(Checked<i64>(0x4000000000000000) + Checked<i64>(0x3fffffffffffffff)).has_overflow());
+    EXPECT((Checked<i64>(0x4000000000000000) + Checked<i64>(0x4000000000000000)).has_overflow());
+    EXPECT(!(Checked<i64>(-0x4000000000000000) + Checked<i64>(-0x4000000000000000)).has_overflow());
+    EXPECT((Checked<i64>(-0x4000000000000001) + Checked<i64>(-0x4000000000000000)).has_overflow());
+
+    EXPECT(!(Checked<i64>(0x4000000000000000) - Checked<i64>(-0x3fffffffffffffff)).has_overflow());
+    EXPECT((Checked<i64>(0x4000000000000000) - Checked<i64>(-0x4000000000000000)).has_overflow());
+    EXPECT(!(Checked<i64>(-0x4000000000000000) - Checked<i64>(0x4000000000000000)).has_overflow());
+    EXPECT((Checked<i64>(-0x4000000000000000) - Checked<i64>(0x4000000000000001)).has_overflow());
+}
+
 TEST_CASE(should_constexpr_default_construct)
 {
     constexpr Checked<int> checked_value {};