How is the HSG "dye test"?

Alissa • 30yo - been with fiancé for 9 years 💍 TTC baby #1 since Sept 2014 ❤️ 1st cycle IVF w. ICSI: in process!
I'm getting one done Mid April and need any info/advice I can get. 
UPDATE: had the test done earlier this week. It was crazy painful. But my tubes looked great:)