+1 to this guy, there is no such angle as 0.
You got your tests wrong.

I had to add to my if statement an equals in my solution to pass the tests : if((a+b)<=180).

During submission I've had a failure in test:
Time: 308ms Passed: 20 Failed: 1 Errors: 1

Testing: 149, 31; Expecting: 0
Expected: 0, instead got: 'The triangle with given angles can't exist'

As I remember geometry an angle in triangle can't be a zero. But this test expects a 0 angle. Or is there so-called flat triangle possible here?