Fixed (the warnings).

I have the same. I used an earlier version as advised below.
Mono 4.2.3
Throws a new error.

Exception System.NullReferenceException: The object reference is not set to an instance of the object

I would like to send the code in one line, but...

tests/Fixture.cs(14,42): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
tests/Fixture.cs(14,57): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
tests/Fixture.cs(15,42): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
tests/Fixture.cs(15,58): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
tests/Fixture.cs(16,44): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity
tests/Fixture.cs(16,65): warning CS0078: The 'l' suffix is easily confused with the digit '1' -- use 'L' for clarity

Is 4+1=5
and 4-1=3
Your array dont contain 3 or 5
It's false