Review usage of cmp.Diff to follow the (want, got) pattern

[vdemeester]

We heavily use cmp.Diff in our tests. Those should follow the (want, got) pattern (or (expected, actual)) when used.
However, if we go through the tests, sometimes it is used in the opposite way (aka (got, want)).

This can become a problem when reviewing the failures of tests as, we are assuming the correct usage when printing out the error (diff.PrintWantGot(d)). This means, in some tests, the error is inverted, it displays "got" as wanted, and "wanted" as got… Which tends to be relatively painful when figuring things out.

// PrintWantGot takes a diff string generated by cmp.Diff and returns it
// in a consistent format for reuse across all of our tests. This
// func assumes that the order of arguments passed to cmp.Diff was
// (want, got) or, in other words, the expectedResult then the actualResult.

We would need to go from the former to the latter.

        // Invalid usage
	if d := cmp.Diff(updatedTR.Status.TaskSpec, expectedStatusSpec); d != "" {
		t.Errorf("expected Status.TaskSpec to match, but differed: %s", diff.PrintWantGot(d))
	}
        // Valid usage
	if d := cmp.Diff(expectedStatusSpec, updatedTR.Status.TaskSpec); d != "" {
		t.Errorf("expected Status.TaskSpec to match, but differed: %s", diff.PrintWantGot(d))
	}

/cc @tektoncd/core-collaborators @tektoncd/core-maintainers

[T3-git]

/assign T3-git

[minhoryang]

Is there any progress on this?

[T3-git]

@minhoryang, I just returned from my vacation and was about to address the issue/task. It seems you have handled this so let me know how to procced.

[minhoryang]

/assign @minhoryang