anyone know how to test for mold in house?

Your nose and eyes do most of it, honestly. A musty smell that's stronger in one room, staining on ceilings or behind furniture against outside walls, paint bubbling. The DIY petri dish kits aren't much use because mould spores are in all air, so they nearly always grow something. If you think it's hidden in a wall, a cheap moisture meter tells you more than a kit will - damp is the cause, the mould is just the symptom.