Mocking objects with Moq when constructor has parameters
Solution 1:
Change the last line to
var syncEngine = new Mock<CustomerSyncEngine>(mockLogger, mockCrm, mockCache).Object;
and it should work
Solution 2:
The last line is giving you a real instance because you are using the new keyword, not mocking CustomerSyncEngine.
You should use Mock.Of<CustomerSyncEngine>()
The only problem with Mocking Concrete types is that Moq would need a public default constructor(with no parameters) OR you need to create the Moq with constructor arg specification. http://www.mockobjects.com/2007/04/test-smell-mocking-concrete-classes.html
The best thing to do would be right click on your class and choose Extract interface.