チャレンジ：テストケース実行

次の3つのテストケースをTestinyプロジェクトに追加し、テスト実行で実行すること。これらはチャットアプリケーション上で実行する必要がある。各テストケースの優先度は適切なレベルに設定可能。

- Test Case ID: TC-01
- Title: Registration with Existing Email
- Precondition:
    1. The user is on the registration page.
    2. An account is already registered using the email "testuser1@example.com".
- Test Steps:
    1. Enter "testuser2" in the "Username" field.
    2. Enter "testuser1@example.com" in the "Email" field.
    3. Enter "examplePassword123" in the "Password" field.
    5. Click the "Register" button.
- Expected Result (Postcondition):
    1. The message "User already exists" should be displayed on the screen.


- Test Case ID: TC-02
- Title: Successful Login
- Precondition:
    1. The user is on the login page.
    2. An account with the username "testuser1" is already registered.
- Test Steps:
    1. Enter a "testuser1" in the "Username" field.
    2. Enter "examplePassword123" in the "Password" field.
    3. Click the "Login" button.
- Expected Result (Postcondition):
    1. The user should be successfully logged in.
    2. The user should be redirected to the chat page where they can see the Chat Box.


- Test Case ID: TC-03
- Title: Sending an empty message in the Chat
- Precondition:
    1. The user is already logged in and is on the chat page.
- Test Steps:
    1. Make sure the chatbox input field is empty.
    2. Click "Send"
- Expected Result (Postcondition):
    1. No message is sent in the chatbox.

テストケースを実行した後、結果を「合格」または「不合格」としてボックスに記入すること。