使用Visual Studio C ++进行单元测试时的链接器错误

我想用Visual Studio单元测试我的C ++项目。将项目中的文件夹添加为测试项目的包含路径之后，尝试编译测试时出现链接器错误：

Severity    Code    Description Project File    Line    Suppression State
Error   LNK2019 unresolved external symbol "public: __thiscall Piece::Piece(enum Color)" (??0Piece@@QAE@W4Color@@@Z) referenced in function "public: __thiscall Bishop::Bishop(enum Color)" (??0Bishop@@QAE@W4Color@@@Z)    ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   
Error   LNK2019 unresolved external symbol "public: __thiscall Board::~Board(void)" (??1Board@@QAE@XZ) referenced in function "public: void __thiscall ChessPlusPlusTests::BishopTests::ValidMovesTest(void)" (?ValidMovesTest@BishopTests@ChessPlusPlusTests@@QAEXXZ)  ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   
Error   LNK2019 unresolved external symbol "public: void __thiscall Board::placePieceAt(class Piece * const,struct Position)" (?placePieceAt@Board@@QAEXQAVPiece@@UPosition@@@Z) referenced in function "public: void __thiscall ChessPlusPlusTests::BishopTests::ValidMovesTest(void)" (?ValidMovesTest@BishopTests@ChessPlusPlusTests@@QAEXXZ)    ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   
Error   LNK2001 unresolved external symbol "public: virtual class std::vector<struct Position,class std::allocator<struct Position> > __thiscall Bishop::getMovesFor(struct Position,class Board &)" (?getMovesFor@Bishop@@UAE?AV?$vector@UPosition@@V?$allocator@UPosition@@@std@@@std@@UPosition@@AAVBoard@@@Z)   ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   
Error   LNK2001 unresolved external symbol "public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall Bishop::toString(void)" (?toString@Bishop@@UAE?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ)    ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   
Error   LNK2001 unresolved external symbol "public: virtual class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall Bishop::toShortString(void)" (?toShortString@Bishop@@UAE?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ)  ChessPlusPlus-Tests D:\Documents\Projects\ChessPlusPlus\ChessPlusPlus-Tests\BishopTests.obj 1   

我的测试源代码：

#include "stdafx.h"
#include "CppUnitTest.h"
#include "Bishop.h"
#include "Board.h"
#include "TestUtils.h"

using namespace Microsoft::VisualStudio::CppUnitTestFramework;

namespace ChessPlusPlusTests
{
    TEST_CLASS(BishopTests)
    {
    public:

        TEST_METHOD(ValidMovesTest)
        {
            // Arrange
            Board board{};
            Bishop *piece = new Bishop{ Color::WHITE };
            Position pos{ 3,3 };
            board.placePieceAt(piece, pos);

            // Act
            auto validPositions = piece->getMovesFor(pos, board);

            // Assert
            TestUtils::AssertPositions(validPositions, {
                0,0,0,0,0,0,0,1,
                1,0,0,0,0,0,1,0,
                0,1,0,0,0,1,0,0,
                0,0,1,0,1,0,0,0,
                0,0,0,0,0,0,0,0,
                0,0,1,0,1,0,0,0,
                0,1,0,0,0,1,0,0,
                1,0,0,0,0,0,1,0,
            });
        }

    };
}

如果不添加包含路径，则测试项目不会编译，因为主项目中包含的头文件依赖于包含路径。

主项目编译正常。

有人可以帮助我了解问题所在吗？

谢谢！