1 files changed, 58 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/BigInt/return-index-predicate-result-is-true.js b/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/BigInt/return-index-predicate-result-is-true.js
new file mode 100644
index 0000000000..28a0bff79e
--- /dev/null
+++ b/js/src/tests/test262/built-ins/TypedArray/prototype/findLastIndex/BigInt/return-index-predicate-result-is-true.js
@@ -0,0 +1,58 @@
+// Copyright (C) 2021 Microsoft. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-%typedarray%.prototype.findlastindex
+description: >
+  Return index if predicate return a boolean true value.
+info: |
+  %TypedArray%.prototype.findLastIndex ( predicate [ , thisArg ] )
+
+  ...
+  5. Let k be len - 1.
+  6. Repeat, while k ≥ 0
+    ...
+    c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
+    d. If testResult is true, return 𝔽(k).
+  ...
+includes: [testBigIntTypedArray.js]
+features: [BigInt, Symbol, TypedArray, array-find-from-last]
+---*/
+
+testWithBigIntTypedArrayConstructors(function(TA) {
+  var sample = new TA([39n, 3n, 9n]);
+  var called = 0;
+
+  var result = sample.findLastIndex(function() {
+    called++;
+    return true;
+  });
+
+  assert.sameValue(result, 2, "returned true on sample[2]");
+  assert.sameValue(called, 1, "predicate was called once");
+
+  called = 0;
+  result = sample.findLastIndex(function(val) {
+    called++;
+    return val === 39n;
+  });
+
+  assert.sameValue(called, 3, "predicate was called three times");
+  assert.sameValue(result, 0, "returned true on sample[0]");
+
+  result = sample.findLastIndex(function() { return "string"; });
+  assert.sameValue(result, 2, "ToBoolean(string)");
+
+  result = sample.findLastIndex(function() { return {}; });
+  assert.sameValue(result, 2, "ToBoolean(object)");
+
+  result = sample.findLastIndex(function() { return Symbol(""); });
+  assert.sameValue(result, 2, "ToBoolean(symbol)");
+
+  result = sample.findLastIndex(function() { return 1; });
+  assert.sameValue(result, 2, "ToBoolean(number)");
+
+  result = sample.findLastIndex(function() { return -1; });
+  assert.sameValue(result, 2, "ToBoolean(negative number)");
+});
+
+reportCompare(0, 0);