expectError() Behavior

[snarkipus]

Not sure if this is an issue or not, but the behavior doesn't quite seem right. If needed, I can try to come up with a minimal test case.

Validator Test Case:

...
    it('Should detect method invocation on a field', () => {
        const mark = validationResult.document.textDocument.getText().lastIndexOf('(');
        expectError(validationResult, "Method invocation on a field",
        {
            offset: mark,
            length: 2,
        });
    });
...

Note: Test passes with length of 2, but fails with length of 1 (off by one in range)

Code langium-tests.ts

...
    if ('offset' in options) {
        const outer = {
            start: validationResult.document.textDocument.positionAt(options.offset),
            end: validationResult.document.textDocument.positionAt(options.offset + options.length - 1)
        };
        filters.push(d => isRangeEqual(outer, d.range));
    }
...

Note: wondering if the end decrement options.offset + options.length - 1 is correct?

Validator in action:

I don't believe that this would have been caught in the tests since it's uncovered in the test report:

[msujew]

I created an issue from this, since this is definitely not intended to work that way #655.

[snarkipus]

Thanks @msujew. I updated the issue you created with a minimal example and a link to some example code. Maybe I'll stumble across a fix - if so I'll submit a PR.