In The Odyssey, how does Odysseus test the loyalty of the swineherd, Eumaeus, and the cowherd, Philoeteus?

When
Odysseus returns to Ithaca after twenty long years abroad, the theme of loyalty begins to
pervade the remaining Books of the epic. In the end, however, there seems to be three categories
of servants at theof the poem: those like Eumaeus, Philoeteus and Eurycleia, who have remained
loyal to Odysseus and Penelope; those like the goatherd Melanthius and some of Penelope's
serving women, who have sided with the suitors and believe Odysseus to be long dead; and finally
those like Phemius, the bard, who served the suitors during Odysseus' absence but after their
slaughter claims he only did so under duress.

This division among his
serving folk means that upon his return Odysseus no longer knows where his friends and enemies
lie. However, the bitterness of Eumaeus' and Phileoteus' language towards the suitors and the
hopeful longing with which they speak of Odysseus' eventual return helps Odysseus to recognize
that they are still faithful servants to their true king....