C# – How to dynamically adjust table column width in RDLC report

Lisa Nicholls gives a complete answer in this thread about dynamically defining a report. You'll want to scroll down some before you get to a useful answer. This thread most directly answers your question about controlling which columns are displayed.

These same techniques can be used to size the columns programmatically, but your code will have to figure out the appropriate column widths.

You'll be able to do that for Hamcrest or Hamcrest-style matchers, but not for Mockito matchers you get from the static methods on org.mockito.Matchers.

In short, methods like same, anyInt, and eq in Mockito are all designed to fit into method calls in when and verify, so they work counterintuitively through side effects. This makes it really hard to consume them and work with them outside of Mockito internals. By contrast, if you limit yourself to using either Matcher (Hamcrest) or ArgumentMatcher (Mockito) instances, you can manipulate those to your heart's content, and with Hamcrest you'll already have a large library of matchers to start with. See my other Q&A here for context.

In short, your matcher would probably look like this.

public class ActionEventMatcher extends ArgumentMatcher<ActionEvent> {
    /* fields here */

    public ActionEventMatcher(
            Matcher<Object> sourceMatcher,
            Matcher<Integer> idMatcher,
            Matcher<String> actionCommandMatcher) { /* save fields here */ }

    @Override
    public boolean matches(Object argument) {
        if (!(argument instanceof ActionEvent))
            return false;
        ActionEvent e = (ActionEvent)argument;

        return this.sourceMatcher.matches(e.getSource())
            && this.idMatcher.matches(e.getId())
            && this.actionCommandMatcher.matches(e.getActionCommand());
    }
}

As a bonus, you can use describeMismatch in Hamcrest 1.3+ to summarize mismatched fields, which might make it easier to determine which aspects of an ActionEvent are failing. (This won't help for verify calls if you don't use an ArgumentCaptor, though, because Mockito treats a non-matching call as "missing A but received B", not "received B but it failed matcher A for these reasons". You'd have to capture the event and use assertEquals to benefit from mismatch descriptions.)