Like Bill pointed out, always get the exposure index first. Then do the development test.
Development test is best done in darkroom with your favorite paper and enlarger light source. Project a processed (first guess at development time) Zone VIII negative with your enlarger so the film base is also showing. Adjust enlarger exposure so the film base just prints black with the least exposure possible. Place coin on white area of the printing paper. If you can see outline of the coin, development is correct.