mod operator tests

vlib/math/math_test.v

@@ -48,3 +48,9 @@ fn test_gamma() {
 	assert math.gamma(5) == 24
 	assert math.log_gamma(4.5) == math.log(math.gamma(4.5))
 }
+
+fn test_mod() {
+	assert 4 % 2 == 0
+	x := 2
+	assert u64(5) % x == 1
+}