Added more tests

tests/programs/negation.q

@@ -1,7 +1,10 @@
 main() {
-	assert f(-32) == 32
+	assert neg(-1) == 1
+	assert neg(1) == -1
+	assert neg(-256) == 256
+	assert neg(256) == -256
 }
 
-f(x) {
+neg(x) {
 	return -x
 }