Fix `BigInt.prototype.toString()` radix checks (#885)

boa/src/builtins/bigint/mod.rs

@@ -140,7 +140,7 @@ impl BigInt {
         } else {
             10
         };
-        if radix < 2 && radix > 36 {
+        if radix < 2 || radix > 36 {
             return ctx
                 .throw_range_error("radix must be an integer at least 2 and no greater than 36");
         }

boa/src/builtins/bigint/tests.rs

@@ -212,6 +212,15 @@ fn to_string() {
     assert_eq!(forward(&mut engine, "1000n.toString(36)"), "\"rs\"");
 }
 
+#[test]
+fn to_string_invalid_radix() {
+    let mut engine = Context::new();
+
+    assert_throws(&mut engine, "10n.toString(null)", "RangeError");
+    assert_throws(&mut engine, "10n.toString(-1)", "RangeError");
+    assert_throws(&mut engine, "10n.toString(37)", "RangeError");
+}
+
 #[test]
 fn as_int_n() {
     let mut engine = Context::new();