from
Bouvier's Law Dictionary, Revised 6th Ed (1856)
TESTATUM, practice. The name of a writ which is issued by the court of one
county, to the sheriff of another county, in the same state, when the
defendant cannot be found in the county where the court is located; for
example, after a judgment has been obtained, and a ca. sa. has been issued,
which has been returned non est inventus, a testatum ca. sa. may be issued
to the sheriff of the county where the defendant is. Vide 20 Vin. Ab. 259; 7
Com. Dig. 424.