assertNotEqual

assertEqual(1, 1);
assertNotEqual(1, 2);

assert(assertEqual("foo", "bar").getExceptionMsg == `("foo" == "bar") failed.`);
assert(assertNotEqual(1, 1).getExceptionMsg == "(1 != 1) failed.");

int x;
int[] y;
static assert(!__traits(compiles, x.assertEqual(y)));