Add ConfigKnobShim GoogleTests (microsoft#254)

## Description

Original PR: microsoft#200

Google Tests for ConfigKnobShimDxeLib and ConfigKnobShimPeiLib
ConfigKnobShimPeiLib is consuming the PPI mock from mu_basecore
(microsoft/mu_basecore#579), so merging this is
pending the mu_basecore PR being merged. Pipelines will fail in the
meantime.

- [ ] Impacts functionality?
- **Functionality** - Does the change ultimately impact how firmware
functions?
- Examples: Add a new library, publish a new PPI, update an algorithm,
...
- [ ] Impacts security?
- **Security** - Does the change have a direct security impact on an
application,
    flow, or firmware?
  - Examples: Crypto algorithm change, buffer overflow fix, parameter
    validation improvement, ...
- [ ] Breaking change?
- **Breaking change** - Will anyone consuming this change experience a
break
    in build or boot behavior?
- Examples: Add a new library class, move a module to a different repo,
call
    a function in a new library class in a pre-existing module, ...
- [x ] Includes tests?
  - **Tests** - Does the change include any explicit test code?
  - Examples: Unit tests, integration tests, robot tests, ...
- [ ] Includes documentation?
- **Documentation** - Does the change contain explicit documentation
additions
    outside direct code modifications (and comments)?
- Examples: Update readme file, add feature readme file, link to
documentation
    on an a separate Web page, ...

## How This Was Tested

Ran the tests using stuart_ci_build.

## Integration Instructions

N/A

SetupDataPkg/Library/ConfigKnobShimLib/ConfigKnobShimDxeLib/GoogleTest/ConfigKnobShimDxeLibGoogleTest.cpp

@@ -0,0 +1,175 @@
+/** @file ConfigKnobShimDxeLibGoogleTest.cpp
+  Unit tests for the ConfigKnobShimDxeLib using GoogleTest
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <Library/GoogleTestLib.h>
+#include <GoogleTest/Library/MockUefiRuntimeServicesTableLib.h>
+extern "C" {
+#include <Uefi.h>
+#include <Library/BaseLib.h>
+#include <Library/DebugLib.h>
+#include <Library/ConfigKnobShimLib.h>
+}
+
+#define CONFIG_KNOB_GUID  {0x52d39693, 0x4f64, 0x4ee6, {0x81, 0xde, 0x45, 0x89, 0x37, 0x72, 0x78, 0x55}}
+
+using namespace testing;
+
+///////////////////////////////////////////////////////////////////////////////
+class GetConfigKnobOverrideFromVariableStorageTest : public Test
+{
+protected:
+StrictMock<MockUefiRuntimeServicesTableLib> RtServicesMock;
+EFI_STATUS Status;
+EFI_GUID ConfigKnobGuid;
+CHAR16 *ConfigKnobName;
+UINT64 ProfileDefaultValue;
+UINTN ProfileDefaultSize;
+UINT64 VariableData;
+UINT64 ConfigKnobData;
+
+// Redefining the Test class's SetUp function for test fixtures.
+void
+SetUp (
+  ) override
+{
+  ConfigKnobGuid      = CONFIG_KNOB_GUID;
+  ConfigKnobName      = (CHAR16 *)L"MyDeadBeefDelivery";
+  ProfileDefaultValue = 0xDEADBEEFDEADBEEF;
+  ProfileDefaultSize  = sizeof (ProfileDefaultValue);
+  VariableData        = 0xBEEF7777BEEF7777;
+  ConfigKnobData      = ProfileDefaultValue;
+}
+};
+
+//
+// Fail to find a cached config knob policy and fail to fetch config knob from
+// variable storage. Then, set the profile default value.
+//
+TEST_F (GetConfigKnobOverrideFromVariableStorageTest, VariableStorageSmallBufferFailure) {
+  // Expect the first GetVariable call to set the correct size
+  // Expect the second call to return an EFI_DEVICE_ERROR
+  EXPECT_CALL (
+    RtServicesMock,
+    gRT_GetVariable (
+      Char16StrEq ((CHAR16 *)L"MyDeadBeefDelivery"), // Example of using Char16 matcher
+      _,
+      _,
+      _,
+      _
+      )
+    )
+    .WillOnce (
+       DoAll (
+         SetArgPointee<3>(sizeof (VariableData)),
+         Return (EFI_BUFFER_TOO_SMALL)
+         )
+       )
+    .WillOnce (
+       Return (EFI_NOT_FOUND)
+       );
+
+  Status = GetConfigKnobOverride (&ConfigKnobGuid, ConfigKnobName, (VOID *)&ConfigKnobData, ProfileDefaultSize);
+
+  ASSERT_EQ (Status, EFI_NOT_FOUND);
+  ASSERT_EQ (ConfigKnobData, ProfileDefaultValue);
+}
+
+//
+// With no cached config knob policy, successfully fetch config knob from
+// variable storage. Then, create cached policy.
+//
+TEST_F (GetConfigKnobOverrideFromVariableStorageTest, VariableStorageSuccess) {
+  // Expect the first GetVariable call to get size
+  EXPECT_CALL (
+    RtServicesMock,
+    gRT_GetVariable
+    )
+    .WillOnce (
+       DoAll (
+         SetArgPointee<3>(sizeof (VariableData)),
+         Return (EFI_BUFFER_TOO_SMALL)
+         )
+       );
+
+  // Expect the second getVariable call to update data
+  // NOTE: in this case, could also simply do another .WillOnce call. But, wanted to show a little variety
+  EXPECT_CALL (
+    RtServicesMock,
+    gRT_GetVariable (
+      _,
+      _,
+      _,
+      _,
+      NotNull ()
+      )
+    )
+    .WillOnce (
+       DoAll (
+         SetArgPointee<3>(sizeof (VariableData)),
+         SetArgBuffer<4>(&VariableData, sizeof (VariableData)),
+         Return (EFI_SUCCESS)
+         )
+       );
+
+  Status = GetConfigKnobOverride (&ConfigKnobGuid, ConfigKnobName, (VOID *)&ConfigKnobData, ProfileDefaultSize);
+
+  ASSERT_EQ (Status, EFI_SUCCESS);
+  ASSERT_EQ (VariableData, ConfigKnobData);
+}
+
+//
+// Fail to find a cached config knob policy and fail to fetch config knob from
+// variable storage. Then, set the profile default value.
+//
+TEST_F (GetConfigKnobOverrideFromVariableStorageTest, VariableStorageNotFoundFailure) {
+  // Expect the first GetVariable call to get size to fail
+  EXPECT_CALL (
+    RtServicesMock,
+    gRT_GetVariable
+    )
+    .WillOnce (
+       Return (EFI_NOT_FOUND)
+       );
+
+  Status = GetConfigKnobOverride (&ConfigKnobGuid, ConfigKnobName, (VOID *)&ConfigKnobData, ProfileDefaultSize);
+
+  ASSERT_EQ (Status, EFI_NOT_FOUND);
+  ASSERT_EQ (ConfigKnobData, ProfileDefaultValue);
+}
+
+/*
+  Fail to find a cached config knob policy and succeed to fetch config knob from
+  variable storage. Fail to match variable size with profile default size. Then, set the profile default value.
+*/
+TEST_F (GetConfigKnobOverrideFromVariableStorageTest, VariableStorageSizeFailure) {
+  // Expect the first GetVariable call to get (non-matching) size
+  EXPECT_CALL (
+    RtServicesMock,
+    gRT_GetVariable
+    )
+    .WillOnce (
+       DoAll (
+         SetArgPointee<3>(sizeof (UINT32)),
+         Return (EFI_BUFFER_TOO_SMALL)
+         )
+       );
+
+  Status = GetConfigKnobOverride (&ConfigKnobGuid, ConfigKnobName, (VOID *)&ConfigKnobData, ProfileDefaultSize);
+  ASSERT_EQ (Status, EFI_BAD_BUFFER_SIZE);
+  ASSERT_EQ (ConfigKnobData, ProfileDefaultValue);
+}
+
+int
+main (
+  int   argc,
+  char  *argv[]
+  )
+{
+  InitGoogleTest (&argc, argv);
+  return RUN_ALL_TESTS ();
+}

SetupDataPkg/Library/ConfigKnobShimLib/ConfigKnobShimDxeLib/GoogleTest/ConfigKnobShimDxeLibGoogleTest.inf

@@ -0,0 +1,34 @@
+## @file
+# Unit test suite for the ConfigKnobShimDxeLib using Google Test
+#
+# Copyright (c) 2022, Intel Corporation. All rights reserved.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+##
+
+[Defines]
+  INF_VERSION         = 0x00010017
+  BASE_NAME           = ConfigKnobShimDxeLibGoogleTest
+  FILE_GUID           = 95B1405E-10E8-4667-84CC-1C2B0A06C424
+  VERSION_STRING      = 1.0
+  MODULE_TYPE         = HOST_APPLICATION
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64
+#
+
+[Sources]
+  ConfigKnobShimDxeLibGoogleTest.cpp
+  ../../ConfigKnobShimLibCommon.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+  SetupDataPkg/SetupDataPkg.dec
+  UnitTestFrameworkPkg/UnitTestFrameworkPkg.dec
+
+[LibraryClasses]
+  GoogleTestLib
+  BaseLib
+  DebugLib
+  ConfigKnobShimLib