something abstract method

Provides a custom matcher.

Each method call after the last matched call (if any) will be passed to the given predicate, along with the values of its (positional) arguments.

For each one, the predicate must either return a boolean or throw a String.

If the predicate returns true, the call is considered a successful match and the next step in the pattern is examined. If this was the last step, then any calls that were not yet matched are ignored and the paints Matcher is considered a success.

If the predicate returns false, then the call is considered uninteresting and the predicate will be called again for the next Canvas call that was made by the RenderObject under test. If this was the last call, then the paints Matcher is considered to have failed.

If the predicate throws a String, then the paints Matcher is considered to have failed. The thrown string is used in the message displayed from the test framework and should be complete sentence describing the problem.