The ornamental design for a teststrip, as shown and described.
FIG. 1 is a perspective view of a test strip showing our new design;
FIG. 2 is a front elevational view thereof;
FIG. 3 is a rear elevational view thereof;
FIG. 4 is a left side elevational view thereof;
FIG. 5 is a right side elevational view thereof;
FIG. 6 is a top plan view thereof; and,
FIG. 7 is a bottom plan view thereof.
The dash-dot broken lines are for defining the bounds of the claimed design only and form no part of the claimed design.
The evenly dotted broken lines, the areas within them, and the areas bounded by both evenly dotted broken lines and solid lines depict portions of the test strip that form no part of the claimed design.