Add API models, mock backend, more tests

tests/testcafe/index.test.ts

@@ -34,4 +34,14 @@ test("Increment button functions correctly", async t => {
   await t.expect(button.textContent).contains("0");
   await t.click(button);
   await t.expect(button.textContent).contains("1");
-});
+});
+
+fixture`Posts from API`.page("http://localhost:3000");
+
+test("At least one post exists", async t => {
+  /**
+   * Test if the API responds with at least one post and it is rendered to the page
+   */
+  const post = Selector(".post");
+  await t.expect(post.exists).ok();
+});