Partial mocking allows you to mock only specific members of an object while keeping the rest intact. Thus, you can continue to work with your existing, original object, not a mock object, with the benefit of being able to test your code in isolation when needed.
[TestMethod]
publicvoidShouldMockInstanceCallPartially()
{
// Arrange
Foo foo = newFoo();
// Just a single method of the original object is mocked.