The ornamental design for a tester for antistaticwriststrap, as shown and described.
FIG. 1 is a perspective view of a tester for antistatic wrist strap;
FIG. 2 is a front view thereof;
FIG. 3 is a rear view thereof;
FIG. 4 is a left side view thereof;
FIG. 5 is a right side view thereof:
FIG. 6 is a top view thereof; and,
FIG. 7 is a bottom view thereof.
The broken lines depict portions of the tester for antistatic wrist strap in which the design is embodied that are not considered part of the claimed design.