public void SubscribeTest()
{
//Arrange:
var testApp = new ApplicationUT(fileSystemVisitor);
var appMock = new Moq.Mock <Application>(fileSystemVisitor)
{
CallBase = true
};
appMock
.Protected()
.Setup <bool>("Subscribe")
.Returns(true);
//Act:
var result = testApp.SubscribeTest();
appMock.Object.Start();
//Assert:
Assert.IsTrue(result);
appMock.Protected().Verify("Subscribe", Times.Once());
}