Added more constructors to CircuitBreaker Exceptions to set inner exc…

[mansoor-omrani]

When the task employed in CircuitBreakerInvoker.Invoke() for executing given action fails and its Status is IsFaulted, we need to pass task.Exception to the new CircuitBreaker exception we want to throw so that it is set in its InnerException. Otherwise we will lose the real exception and the user who used CircuitBreaker will not know what the source of failure was.

[alexandrnikitin]

@mansoor-omrani Thank you for the PR. I'm not sure I understand the intention. The Task.Wait method rethrows an exception thrown during the execution of the task. The inner exception should contain the exception. Here're tests that cover the use case.

CircuitBreaker.Net/tests/CircuitBreaker.Net.Tests/CircuitBreakerInvokerTests.cs

Line 37 in 8c05943

public class InvokeThroughTests : CircuitBreakerInvokerTests

Can you please share your use case? Or maybe even a test that covers it.

[alexandrnikitin]

I reviewed your recent changes. I'm still not sure that I get it. CircuitBreakerOpenException is meant to indicate that the circuit is open. CircuitBreaker.Execute throws an exception if execution fails so you can handle it in your code. Why do you want to wrap it into CircuitBreakerOpenException?

[mansoor-omrani]

@alexandrnikitin Hi alex. The requirement for the change I made was to embed the potential exception that occurs in user's given action in the CircuitBreaker exception (in its InnerException).

Currently CircuitBreaker exceptions don't bring out exceptions that happen in user's action. The InnerException is null.

You can check that with the following test:

[Fact]
public void ExepectInnerExceptionWhenActionFails()
{
   var state = Substitute.For<ICircuitBreakerState>();
   var e = Assert.ThrowsAny<Exception>(() => _sut.InvokeThrough(state, () => { throw new ArgumentNullException(); }, TimeSpan.FromMilliseconds(100)));
   state.Received().InvocationFails();
   Assert.IsType<ArgumentNullException>(e.InnerException);
}

But I noticed other problems with the Invoke() and InvokeAsync() as well.

I'm working on the code. I try to explain them in the near future.