diff --git a/implementation-contributed/javascriptcore/stress/object-from-entries.js b/implementation-contributed/javascriptcore/stress/object-from-entries.js
new file mode 100644
index 0000000000..9e3befcc8c
--- /dev/null
+++ b/implementation-contributed/javascriptcore/stress/object-from-entries.js
@@ -0,0 +1,196 @@
+function shouldBe(actual, expected) {
+    if (actual !== expected)
+        throw new Error('bad value: ' + actual);
+}
+
+function shouldThrow(func, errorMessage) {
+    var errorThrown = false;
+    var error = null;
+    try {
+        func();
+    } catch (e) {
+        errorThrown = true;
+        error = e;
+    }
+    if (!errorThrown)
+        throw new Error('not thrown');
+    if (String(error) !== errorMessage)
+        throw new Error(`bad error: ${String(error)}`);
+}
+
+shouldBe(JSON.stringify(Object.getOwnPropertyDescriptor(Object, "fromEntries")), `{"writable":true,"enumerable":false,"configurable":true}`);
+shouldBe(Object.fromEntries.length, 1);
+
+shouldThrow(() => Object.fromEntries(null), `TypeError: null is not an object`);
+shouldThrow(() => Object.fromEntries(undefined), `TypeError: undefined is not an object`);
+shouldThrow(() => Object.fromEntries(0), `TypeError: undefined is not a function`);
+shouldThrow(() => Object.fromEntries(true), `TypeError: undefined is not a function`);
+shouldThrow(() => Object.fromEntries(Symbol("Cocoa")), `TypeError: undefined is not a function`);
+shouldThrow(() => Object.fromEntries("Cocoa"), `TypeError: Object.fromEntries requires the first iterable parameter yields objects`);
+shouldThrow(() => Object.fromEntries([0]), `TypeError: Object.fromEntries requires the first iterable parameter yields objects`);
+shouldThrow(() => Object.fromEntries([["Cocoa", "Cappuccino"], 0]), `TypeError: Object.fromEntries requires the first iterable parameter yields objects`);
+
+{
+    let object = Object.fromEntries([]);
+    shouldBe(JSON.stringify(object), `{}`);
+}
+{
+    let object = Object.fromEntries([["Cocoa", "Cappuccino"]]);
+    shouldBe(JSON.stringify(object), `{"Cocoa":"Cappuccino"}`);
+    shouldBe(JSON.stringify(Object.getOwnPropertyDescriptor(object, "Cocoa")), `{"value":"Cappuccino","writable":true,"enumerable":true,"configurable":true}`);
+}
+{
+    let obj = { abc: 1, def: 2, ghij: 3 };
+    let res = Object.fromEntries(
+        Object.entries(obj)
+            .filter(([ key, val ]) => key.length === 3)
+            .map(([ key, val ]) => [ key, val * 2 ])
+        );
+    shouldBe(JSON.stringify(res), `{"abc":2,"def":4}`);
+}
+{
+    let map = new Map([ [ 'a', 1 ], [ 'b', 2 ], [ 'c', 3 ] ]);
+    let obj = Object.fromEntries(map);
+    shouldBe(JSON.stringify(obj), `{"a":1,"b":2,"c":3}`);
+}
+{
+    let arr = [ { name: 'Alice', age: 40 }, { name: 'Bob', age: 36 } ];
+    let obj = Object.fromEntries(arr.map(({ name, age }) => [ name, age ]));
+    shouldBe(JSON.stringify(obj), `{"Alice":40,"Bob":36}`);
+}
+{
+    Object.defineProperty(Object.prototype, "bad", {
+        get() { throw new Error("out"); },
+        set(v) { throw new Error("out"); }
+    });
+    shouldThrow(() => {
+        let object = {};
+        object.bad;
+    }, `Error: out`);
+    shouldThrow(() => {
+        let object = {};
+        object.bad = 42;
+    }, `Error: out`);
+    let object = Object.fromEntries([["bad", "value"]]);
+    shouldBe(JSON.stringify(object), `{"bad":"value"}`);
+}
+{
+    var counter = 0;
+    class Recorder {
+        constructor(first, second)
+        {
+            this.first = first;
+            this.second = second;
+        }
+
+        get 0()
+        {
+            shouldBe(counter++, this.first);
+            return this.first;
+        }
+
+        get 1()
+        {
+            shouldBe(counter++, this.second);
+            return this.second;
+        }
+    }
+    var result = Object.fromEntries([new Recorder(0, 1), new Recorder(2, 3)]);
+    shouldBe(result[0], 1);
+    shouldBe(result[2], 3);
+    shouldBe(counter, 4);
+}
+{
+    class Iterable {
+        constructor()
+        {
+        }
+
+        *[Symbol.iterator]()
+        {
+            yield [0, 1];
+            yield [1, 2];
+        }
+    }
+
+    var result = Object.fromEntries(new Iterable);
+    shouldBe(result[0], 1);
+    shouldBe(result[1], 2);
+}
+{
+    class Iterator {
+        constructor()
+        {
+            this.index = 0;
+        }
+
+        next()
+        {
+            if (this.index === 4)
+                throw new Error("out");
+
+            this.index++;
+            return {
+                value: [0, 1],
+                done: false
+            };
+        }
+    }
+
+    class Iterable {
+        constructor()
+        {
+        }
+
+        [Symbol.iterator]()
+        {
+            return new Iterator;
+        }
+    }
+
+    try {
+        Object.fromEntries(new Iterable);
+    } catch (error) {
+        shouldBe(String(error), `Error: out`);
+    }
+}
+{
+    let array = [[], ['c', 'd']];
+    let object = Object.fromEntries(array);
+    shouldBe(JSON.stringify(Object.keys(object).sort()), `["c","undefined"]`);
+    shouldBe(object.c, 'd');
+    shouldBe(object.undefined, undefined);
+}
+{
+    let symbol = Symbol('Cocoa');
+    let array = [[symbol, 42]];
+    let object = Object.fromEntries(array);
+    shouldBe(Object.getOwnPropertySymbols(object).length, 1);
+    shouldBe(Object.getOwnPropertyNames(object).length, 0);
+    shouldBe(object.hasOwnProperty(symbol), true);
+    shouldBe(object[symbol], 42);
+}
+{
+    Object.defineProperty(Object.prototype, "hello", {
+        get() {
+            throw new Error("out");
+        },
+        set() {
+            throw new Error("out");
+        }
+    });
+    let result = Object.fromEntries([["hello", 42]]);
+    shouldBe(result.hello, 42);
+}
+{
+    let array = [['a', 'b'], ['c', 'd']];
+    Object.defineProperty(array, 0, {
+        get()
+        {
+            array.push(['e', 'f']);
+            return ['a', 'b'];
+        }
+    });
+    let object = Object.fromEntries(array);
+    shouldBe(JSON.stringify(object), `{"a":"b","c":"d","e":"f"}`);
+}
diff --git a/implementation-contributed/javascriptcore/stress/regress-189227-watchdog-on-infinite-loop.js b/implementation-contributed/javascriptcore/stress/regress-189227-watchdog-on-infinite-loop.js
new file mode 100644
index 0000000000..38e06777ea
--- /dev/null
+++ b/implementation-contributed/javascriptcore/stress/regress-189227-watchdog-on-infinite-loop.js
@@ -0,0 +1,4 @@
+//@ requireOptions("--watchdog=20", "--jitPolicyScale=0", "--watchdog-exception-ok")
+
+// This test should not time out.
+while (1) { }