Adding MockRNG to the Google Test Mock (#668)

# Preface

Please ensure you have read the [contribution
docs](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md) prior
to submitting the pull request. In particular,
[pull request
guidelines](https://github.com/microsoft/mu/blob/master/CONTRIBUTING.md#pull-request-best-practices).

## Description

Adds MockRNG to the Google Test Mock

For each item, place an "x" in between `[` and `]` if true. Example:
`[x]`.
_(you can also check items in the GitHub UI)_

- [ ] Impacts functionality?
  - **Functionality** - No
- [ ] Impacts security?
  - **Security** - No
- [ ] Breaking change?
  - **Breaking change** - No
- [ ] Includes tests?
  - **Tests** - No
- [ ] Includes documentation?
  - **Documentation** - No
  
## How This Was Tested

Local Tests

## Integration Instructions

N/A

MdePkg/Test/Mock/Include/GoogleTest/Protocol/MockRng.h

@@ -0,0 +1,47 @@
+/** @file
+  This file declares a mock of Rng Protocol.
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#ifndef MOCK_RNG_H
+#define MOCK_RNG_H
+
+#include <Library/GoogleTestLib.h>
+#include <Library/FunctionMockLib.h>
+
+extern "C" {
+  #include <Uefi.h>
+  #include <Protocol\Rng.h>
+}
+
+struct MockRng {
+  MOCK_INTERFACE_DECLARATION (MockRng);
+
+  MOCK_FUNCTION_DECLARATION (
+    EFI_STATUS
+    GetInfo (
+      IN EFI_RNG_PROTOCOL             *This,
+      IN OUT UINTN                    *RNGAlgorithmListSize,
+      OUT EFI_RNG_ALGORITHM           *RNGAlgorithmList
+      )
+    );
+
+  MOCK_FUNCTION_DECLARATION (
+    EFI_STATUS
+    GetRNG (
+      IN EFI_RNG_PROTOCOL             *This,
+      IN EFI_RNG_ALGORITHM            *RNGAlgorithmList,
+      IN UINTN                        RNGAlgorithmListSize,
+      IN OUT UINT8                    *RandomNumber,
+      IN UINTN                        RandomNumberLength
+      )
+    );
+};
+
+extern "C" {
+  extern EFI_RNG_PROTOCOL  *gRngProtocol;
+}
+
+#endif // MOCK_RNG_H

MdePkg/Test/Mock/Library/GoogleTest/MockUefiBootServicesTableLib/MockUefiBootServicesTableLib.cpp

@@ -63,5 +63,7 @@ static EFI_BOOT_SERVICES  LocalBs = {
 };
 
 extern "C" {
-  EFI_BOOT_SERVICES  *gBS = &LocalBs;
+  EFI_BOOT_SERVICES  *gBS         = &LocalBs;
+  EFI_HANDLE         gImageHandle = NULL;
+  EFI_SYSTEM_TABLE   *gST         = NULL;
 }

MdePkg/Test/Mock/Library/GoogleTest/Protocol/MockRng.cpp

@@ -0,0 +1,21 @@
+/** @file MockRng.cpp
+  Google Test mock for Rng Protocol
+
+  Copyright (c) Microsoft Corporation.
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+**/
+
+#include <GoogleTest/Protocol/MockRng.h>
+
+MOCK_INTERFACE_DEFINITION (MockRng);
+MOCK_FUNCTION_DEFINITION (MockRng, GetInfo, 3, EFIAPI);
+MOCK_FUNCTION_DEFINITION (MockRng, GetRng, 5, EFIAPI);
+
+EFI_RNG_PROTOCOL  RNG_PROTOCOL_INSTANCE = {
+  GetInfo, // EFI_RNG_GET_INFO
+  GetRng   // EFI_RNG_GET_RNG
+};
+
+extern "C" {
+  EFI_RNG_PROTOCOL  *gRngProtocol = &RNG_PROTOCOL_INSTANCE;
+}