To keep the test executing time within feasible limits, parallel testing is often needed. Suppose there is a test set of 90 test cases that usually takes two hours to run, where the longest execution time of an individual test is five minutes. When running 90 parallel tests, the total execution time will be the time of the longest test – five minutes!
But parallel testing is easier said than done, it requires specific attention in the test strategy and setup of the tests. The tests must be independent, both in execution and test data. Tests cannot use the same test data and when two tests require a database change, running those tests parallel will require specific activities.