LibCrypto+LibJS: Fix broken subtraction of two negative signed bigints

Found by oss-fuzz: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=29326

1 files changed, 8 insertions, 0 deletions

diff --git a/Libraries/LibJS/Tests/builtins/BigInt/bigint-minus.js b/Libraries/LibJS/Tests/builtins/BigInt/bigint-minus.js
new file mode 100644
index 0000000000..5d88f85ce2
--- /dev/null
+++ b/Libraries/LibJS/Tests/builtins/BigInt/bigint-minus.js
@@ -0,0 +1,8 @@
+describe("minus behavior", () => {
+    test("the basics", () => {
+        expect(3n - 4n).toBe(-1n);
+        expect(3n - -4n).toBe(7n);
+        expect(-3n - -4n).toBe(-1n);
+        expect(-3n - 4n).toBe(-7n);
+    });
+});