the dye test is called an HSG:
Here is some info on it magic incase they say you need one:
Hysterosalpingogram
A hysterosalpingogram (HSG) is an X-ray test that looks at the inside of the uterus and fallopian tubes and the area around them. It often is done for women who are having a hard time becoming pregnant (infertile).
During a hysterosalpingogram, a dye (contrast material) is put through a thin tube that is put through the vagina and into the uterus. Because the uterus and the fallopian tubes are hooked together, the dye will flow into the fallopian tubes. Pictures are taken using a steady beam of X-ray (fluoroscopy) as the dye passes through the uterus and fallopian tubes. The pictures can show problems such as an injury or abnormal structure of the uterus or fallopian tubes, or a blockage that would prevent an egg moving through a fallopian tube to the uterus. A blockage also could prevent sperm from moving into a fallopian tube and joining (fertilizing) an egg. A hysterosalpingogram also may find problems on the inside of the uterus that prevent a fertilized egg from attaching (implanting) to the uterine wall. See an illustration of a hysterosalpingogram.
Why It Is Done
A hysterosalpingogram is done to:
Find a blocked fallopian tube. The test often is done for a woman who is having a hard time becoming pregnant. An infection may cause severe scarring of the fallopian tubes and block the tubes, preventing pregnancy. Occasionally the dye used during a hysterosalpingogram will push through and open a blocked tube.
Find problems in the uterus, such as an abnormal shape or structure, an injury, polyps, fibroids, adhesions, or a foreign object in the uterus. These types of problems may cause painful menstrual periods or repeated miscarriages.
See whether surgery to reverse a tubal ligation has been successful.