[FIX] component: prevent rendering if not mounted

src/component.ts

@@ -238,7 +238,7 @@ export class Component<
   }
 
   async render(force: boolean = false, patchQueue?: any[]): Promise<void> {
-    if (this.__owl__.isDestroyed) {
+    if (!this.__owl__.isMounted) {
       return;
     }
     const shouldCallPatchHooks: boolean = !patchQueue;

tests/component.test.ts

@@ -87,6 +87,16 @@ describe("basic widget properties", () => {
   });
 
   test("can be clicked on and updated", async () => {
+    const counter = new Counter(env);
+    await counter.mount(fixture);
+    expect(fixture.innerHTML).toBe("<div>0<button>Inc</button></div>");
+    const button = (<HTMLElement>counter.el).getElementsByTagName("button")[0];
+    await button.click();
+    await nextTick();
+    expect(fixture.innerHTML).toBe("<div>1<button>Inc</button></div>");
+  });
+
+  test("cannot be clicked on and updated if not in DOM", async () => {
     const counter = new Counter(env);
     const target = document.createElement("div");
     await counter.mount(target);
@@ -94,7 +104,8 @@ describe("basic widget properties", () => {
     const button = (<HTMLElement>counter.el).getElementsByTagName("button")[0];
     await button.click();
     await nextTick();
-    expect(target.innerHTML).toBe("<div>1<button>Inc</button></div>");
+    expect(target.innerHTML).toBe("<div>0<button>Inc</button></div>");
+    expect(counter.state.counter).toBe(1);
   });
 
   test("widget style and classname", async () => {