Add e2e tests for completions

e2e/lib/Console.js

@@ -0,0 +1,33 @@
+class Console {
+  constructor(session) {
+    this.session = session;
+  }
+
+  async sendKeys(...keys) {
+    let input = await this.session.findElementByCSS('input');
+    input.sendKeys(...keys);
+  }
+
+  async getCompletions() {
+    return await this.session.executeScript(() => {
+      let items = document.querySelectorAll('.vimvixen-console-completion > li');
+      if (items.length === 0) {
+        throw new Error('completion items not found');
+      }
+
+      let objs = [];
+      for (let li of items) {
+        if (li.classList.contains('vimvixen-console-completion-title')) {
+          objs.push({ type: 'title', text: li.textContent.trim() });
+        } else if ('vimvixen-console-completion-item') {
+          objs.push({ type: 'item', text: li.textContent.trim() });
+        } else {
+          throw new Error(`unexpected class: ${li.className}`);
+        }
+      }
+      return objs;
+    });
+  }
+}
+
+module.exports = Console;