1 files changed, 64 insertions, 0 deletions
diff --git a/js/src/tests/test262/built-ins/Array/prototype/findLastIndex/return-index-predicate-result-is-true.js b/js/src/tests/test262/built-ins/Array/prototype/findLastIndex/return-index-predicate-result-is-true.js
new file mode 100644
index 0000000000..9df93fb9e4
--- /dev/null
+++ b/js/src/tests/test262/built-ins/Array/prototype/findLastIndex/return-index-predicate-result-is-true.js
@@ -0,0 +1,64 @@
+// Copyright (C) 2021 Microsoft. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+/*---
+esid: sec-array.prototype.findlastindex
+description: >
+  Return index if predicate return a boolean true value.
+info: |
+  Array.prototype.findLastIndex ( predicate[ , thisArg ] )
+
+  ...
+  5. Repeat, while k ≥ 0,
+    ...
+    c. Let testResult be ! ToBoolean(? Call(predicate, thisArg, « kValue, 𝔽(k), O »)).
+    d. If testResult is true, return 𝔽(k).
+  ...
+features: [Symbol, array-find-from-last]
+---*/
+
+var arr = ['Shoes', 'Car', 'Bike'];
+var called = 0;
+
+var result = arr.findLastIndex(function() {
+  called++;
+  return true;
+});
+
+assert.sameValue(result, 2);
+assert.sameValue(called, 1, 'predicate was called once');
+
+called = 0;
+result = arr.findLastIndex(function(val) {
+  called++;
+  return val === 'Shoes';
+});
+
+assert.sameValue(called, 3, 'predicate was called three times');
+assert.sameValue(result, 0);
+
+result = arr.findLastIndex(function() {
+  return 'string';
+});
+assert.sameValue(result, 2, 'coerced string');
+
+result = arr.findLastIndex(function() {
+  return {};
+});
+assert.sameValue(result, 2, 'coerced object');
+
+result = arr.findLastIndex(function() {
+  return Symbol('');
+});
+assert.sameValue(result, 2, 'coerced Symbol');
+
+result = arr.findLastIndex(function() {
+  return 1;
+});
+assert.sameValue(result, 2, 'coerced number');
+
+result = arr.findLastIndex(function() {
+  return -1;
+});
+assert.sameValue(result, 2, 'coerced negative number');
+
+reportCompare(0, 0);