fix floor div for int

Shitong Wen · Shitong Wen · commit 50c119a50300 · 2019-05-10T14:21:09.000+08:00
diff --git a/tests/snippets/ints.py b/tests/snippets/ints.py
@@ -64,6 +64,10 @@
 assert (2).__pow__(3.0) == NotImplemented
 assert (2).__rpow__(3.0) == NotImplemented
 
+assert 10 // 4 == 2
+assert -10 // 4 == -3
+assert 10 // -4 == -3
+assert -10 // -4 == 2
 
 assert int() == 0
 assert int("101", 2) == 5
diff --git a/vm/src/obj/objint.rs b/vm/src/obj/objint.rs
@@ -260,7 +260,8 @@ impl PyInt {
         if objtype::isinstance(&other, &vm.ctx.int_type()) {
             let v2 = get_value(&other);
             if *v2 != BigInt::zero() {
-                Ok(vm.ctx.new_int((&self.value) / v2))
+                let modulo = (&self.value % v2 + v2) % v2;
+                Ok(vm.ctx.new_int((&self.value - modulo) / v2))
             } else {
                 Err(vm.new_zero_division_error("integer floordiv by zero".to_string()))
             }
