command.variantSetIds = Lists.newArrayList("v1", "v2");
Mockito.when(variantSets.get("v1")).thenReturn(variantSetGet);
Mockito.when(variantSets.get("v2")).thenReturn(variantSetGet);
Mockito.when(variantSetGet.execute()).thenReturn(
new VariantSet().setId("id1"),
new VariantSet().setId("id2"));
command.handleRequest(genomics);
String output = outContent.toString();
assertTrue(output, output.contains("id1"));