Does the system test solution on all tests?

I want to know, what time my solution runs in. I wrote a program that doesn’t need any input and outputs a string that is going to get Wrong Answer outcome on any input test. Does the system always test the program until the first unpassed test? Is the time that I get in “My submissions” table the running time of my program that was runned once?

It is until the first failed test file. The program is tested under one or more test files. A single test file contains input under specifications in the problem.

If your program gave wrong answer for first test file then it is run-time of one execution. If luckily it managed to give output for first few test files then it would be sum of execution times of all the runs.