[libc-commits] [libc] [libc] wmemcpy implementation (PR #142070)

[Michael Jones via libc-commits]

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@@ -0,0 +1,61 @@
+//===-- Unittests for wmemcpy ---------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "hdr/types/size_t.h"
+#include "hdr/types/wchar_t.h"
+#include "src/wchar/wmemcpy.h"
+#include "test/UnitTest/Test.h"
+
+TEST(LlvmLibcWMemcpyTest, CopyIntoEmpty) {
+  wchar_t dest[10] = {};
+  const wchar_t *src = L"abcde";
+  LIBC_NAMESPACE::wmemcpy(dest, src, 6);
+  ASSERT_TRUE(src[0] == dest[0]);
+  ASSERT_TRUE(src[1] == dest[1]);
+  ASSERT_TRUE(src[2] == dest[2]);
+  ASSERT_TRUE(src[3] == dest[3]);
+  ASSERT_TRUE(src[4] == dest[4]);
+  ASSERT_TRUE(src[5] == dest[5]);
+}
+
+TEST(LlvmLibcWMemcpyTest, CopyFullString) {
+  // After copying, strings should be the same.
+  wchar_t dest[10] = {};
+  const wchar_t *src = L"abcde";
+  LIBC_NAMESPACE::wmemcpy(dest, src, 6);
+  ASSERT_TRUE(src[0] == dest[0]);
+  ASSERT_TRUE(src[1] == dest[1]);
+  ASSERT_TRUE(src[2] == dest[2]);
+  ASSERT_TRUE(src[3] == dest[3]);
+  ASSERT_TRUE(src[4] == dest[4]);
+  ASSERT_TRUE(src[5] == dest[5]);
+}
+
+TEST(LlvmLibcWMemcpyTest, CopyPartialString) {
+  // After copying, only first two characters should be the same.
+  wchar_t dest[10] = {};
+  const wchar_t *src = L"abcde";
+  LIBC_NAMESPACE::wmemcpy(dest, src, 2);
+  ASSERT_TRUE(src[0] == dest[0]);
+  ASSERT_TRUE(src[1] == dest[1]);
+  ASSERT_TRUE(src[2] != dest[2]);
+  ASSERT_TRUE(src[3] != dest[3]);
+  ASSERT_TRUE(src[4] != dest[4]);
+}
+
+TEST(LlvmLibcWMemcpyTest, CopyZeroCharacters) {
+  // Copying 0 characters should not change the string
+  wchar_t dest[10] = {};
+  const wchar_t *src = L"abcde";
+  LIBC_NAMESPACE::wmemcpy(dest, src, 0);
+  ASSERT_TRUE(src[0] != dest[0]);
+  ASSERT_TRUE(src[1] != dest[1]);
+  ASSERT_TRUE(src[2] != dest[2]);
+  ASSERT_TRUE(src[3] != dest[3]);
+  ASSERT_TRUE(src[4] != dest[4]);
----------------
michaelrj-google wrote:

it would be more helpful to assert that `dest` is still the same as it was before the copy, not just not equal to `src`.

https://github.com/llvm/llvm-project/pull/142070