"Type mismatch" is because GHAssertEquals requires that both arguments be the same type. [caseArray count]
returns an unsigned integer. This doesn't match 627 which is a signed integer. So instead, compare against an unsigned 627, namely 627U
:
GHAssertEquals([caseArray count], 627U, @"array count equals");
Alternatively, you could use OCHamcrest to say
assertThat(caseArray, hasCountOf(627));
(OCHamcrest is compatible with GHUnit.)