I found an online Irish test on ranganna.com today – it contains 100 questions of ever increasing difficulty and gives you a idea of your level of Irish. It’s available with instructions in Irish and English and has a seven-level marking scheme ranging from beginner to advanced.
I just took the test and got 69/100 or level 5 (Advanced) – I could understand almost all the questions, but my knowledge of the finer points of Irish grammar and orthography could be better. I’m happy with this as my main focus with Irish is understanding, speaking and reading it well.
After you have taken the test it shows you your answers with the incorrect ones highlighted and the correct ones indicated – a useful feature. It also has some suggestions for learning more Irish.