The ornamental design for a testingdevice, as shown and described.
FIG. 1 is a perspective view of a testing device showing our new design;
FIG. 2 is a top view of the testing device of FIG. 1;
FIG. 3 is a right side view of FIG. 1, which is symmetrical with a left side view;
FIG. 4 is a front elevational view of FIG. 1
FIG. 5 is a rear elevational view of FIG. 1; and,
FIG. 6 is a bottom view of FIG. 1.
The broken lines illustrate unclaimed or environmental features that form no part of the claimed design. The portions between the pairs of closely adjacent, spaced jagged lines in the drawings are broken away to indicate no particular length or width, and such pairs of jagged lines themselves form no part of the claimed design. The materials that may be visible between the jagged lines have been removed for clarity.