MdeModulePkg/Library/UefiSortLib: Add GoogleTestLib example

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=4389

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Signed-off-by: Chris Johnson <chris.n.johnson@intel.com>
Reviewed-by: Oliver Smith-Denny <osde@linux.microsoft.com>
Reviewed-by: Michael D Kinney <michael.d.kinney@intel.com>

MdeModulePkg/Library/UefiSortLib/GoogleTest/UefiSortLibGoogleTest.cpp

@@ -0,0 +1,61 @@
+/** @file
+  Unit tests for the implementation of UefiSortLib.
+
+  Copyright (c) 2022, Intel Corporation. All rights reserved.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+#include <Library/GoogleTestLib.h>
+
+extern "C" {
+  #include <Uefi.h>
+  #include <Library/SortLib.h>
+}
+
+using namespace testing;
+
+INTN
+EFIAPI
+CompareUint32 (
+  IN CONST VOID  *Left,
+  IN CONST VOID  *Right
+  )
+{
+  if (*(UINT32*)Right > *(UINT32*)Left) {
+    return 1;
+  } else if (*(UINT32*)Right < *(UINT32*)Left) {
+    return -1;
+  }
+
+  return 0;
+}
+
+// Test PerformQuickSort() API from UefiSortLib to verify a UINT32 array
+// with 9 elements in ascending order is sorted into descending order.
+TEST(PerformQuickSortTest, SortUint32AscendingArray_Size9) {
+  CONST UINT32 ArraySize = 9;
+  UINT32       BuffActual[ArraySize];
+  UINT32       BuffExpected[ArraySize];
+
+  for (UINT32 Index = 0; Index < ArraySize; Index++) {
+    BuffActual[Index] = Index + 1;
+    BuffExpected[Index] = ArraySize - Index;
+  }
+
+  PerformQuickSort (BuffActual, (UINTN)ArraySize, sizeof(UINT32), (SORT_COMPARE)CompareUint32);
+  EXPECT_THAT(BuffActual, ElementsAreArray(BuffExpected, ArraySize));
+}
+
+// Test StringCompare() API from UefiSortLib to verify the comparison
+// succeeds when the same buffer is compared with itself.
+TEST(StringCompareTest, CompareSameBuffer) {
+  INTN           RetVal;
+  CONST CHAR16  *Buffer = (CHAR16*)L"abcdefg";
+
+  RetVal = StringCompare (&Buffer, &Buffer);
+  EXPECT_EQ(RetVal, 0);
+}
+
+int main(int argc, char* argv[]) {
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}