diff --git a/test/src/Counter.tsx b/test/src/Counter.tsx
new file mode 100644
index 0000000..4f6712b
--- /dev/null
+++ b/test/src/Counter.tsx
@@ -0,0 +1,22 @@
+interface CounterStore {
+    value: number;
+}
+
+const Counter = HUI.define<{}, HUI.Store<CounterStore, {}>, HUI.EmptyStore>('Counter', {
+
+    state: ['value'],
+
+    defaultStore: {
+        value: 0
+    },
+
+    render(props, store) {
+        return (
+            <HUI.Fragment>
+                <button onclick={() => store.inc('value')}>Click me!</button>
+                <p>Count: {store.get('value')}</p>
+            </HUI.Fragment>
+        );
+    }
+
+});
diff --git a/test/src/Dialog.tsx b/test/src/Dialog.tsx
index 7f155bc..a37f0ea 100644
--- a/test/src/Dialog.tsx
+++ b/test/src/Dialog.tsx
@@ -27,7 +27,10 @@ const Dialog = HUI.define<{}, HUI.Store<DialogStore, DialogStoreHandlers>, HUI.E
                 {store.get('on') && [
                     <p>(Dialog window is shown.)</p>,
                     <HUI.Portal>
+                        {undefined}
                         <p attr={{ style: 'color: blue;' }}>[Dialog window]</p>
+                        {null}
+                        {Object}
                     </HUI.Portal>
                 ]}
             </HUI.Fragment>
diff --git a/test/src/test.tsx b/test/src/test.tsx
index 224d70a..c064c7f 100644
--- a/test/src/test.tsx
+++ b/test/src/test.tsx
@@ -9,6 +9,8 @@ type TestContext = HUI.Store<{
 
 const SVG_NS = 'http://www.w3.org/2000/svg';
 
+HUI.tick = cb => { setTimeout(cb, 500) };
+
 HUI.render<TestContext>(
     (
 
@@ -18,6 +20,10 @@ HUI.render<TestContext>(
 
             <hr />
 
+            <Counter />
+
+            <hr />
+
             Global Timer:<br />
             <Timer start={100} />
 
@@ -37,7 +43,9 @@ HUI.render<TestContext>(
 
             <p>SVG test:</p>
 
-            <svg xmlns={SVG_NS} attr={{ width: '100', height: '100' }} style={{ 'box-shadow': '0 0 10px #999' }}>
+            <svg xmlns={SVG_NS}
+                attr={{ width: '100', height: '100' }}
+                style={{ 'box-shadow': '0 0 10px #999' }}>
                 <path
                     xmlns={SVG_NS}
                     d="M 10 40 C 20 80 80 80 90 40"