// Shape.h -- this would be A.dll
    #pragma once

	// Notice the conditional
    #ifdef SHAPE_EXPORTS
    #define SHAPE_API __declspec(dllexport)
	#else
    #define SHAPE_API __declspec(dllimport)
	#endif

    class SHAPE_API Shape /*: public IShape*/
    {
    public:
        Shape();
        Shape(int sides, int sideLength, int apothem);
        ~Shape();

        int Perimeter();
        double Area();
    private:
        int sides;
        int sideLength;
        int apothem;
    };

    // Shape.cpp

	// Do it before including the header to get dllexport
    #define SHAPE_EXPORTS

    #include "stdafx.h"
    #include "Shape.h"

    Shape::Shape() : sides(0), sideLength(0), apothem(0)
    {
    }

    Shape::Shape(int sides, int sideLength, int apothem) : sides(sides), sideLength(sideLength), apothem(apothem)
    {
    }

    Shape::~Shape()
    {
    }

    double Shape::Area()
    {
        if (sides == 1 || sides == 2)
        {
            return -1;
        }

        return .5 * Perimeter() * apothem;
    }

    int Shape::Perimeter()
    {
        return sideLength * sides;
    }

    // ShapesTester.h - this would be B.dll
    #include "../TestHarness/ITest.h"

    class ShapesTester : ITest
    {
    public:
        ShapesTester();
        ~ShapesTester();

        bool Test() override;
        ShapesTester & ShapesTesterFactory();

    private:
    };

    // ShapesTester.cpp
    #include "stdafx.h"
    #include "ShapesTester.h"
    #include "Shape.h"

    ShapesTester::ShapesTester()
    {
    }


    ShapesTester::~ShapesTester()
    {
    }

    bool ShapesTester::Test()
    {
        Shape myShape = Shape(3, 9, 5); // error here; Cannot resolve symbol 'Shape'

        return myShape.Area() == 67.5;
    }

    ShapesTester & ShapesTesterFactory()
    {
        ShapesTester * tester = new ShapesTester();

        return *tester;
    }