Add data-driven test cases

Drive the sign-in form with a table of inputs and expected outcomes instead of copy-pasted tests.

1. 1Define cases: ("", "Test@123") → #username-error “Email is required”; ("not-an-email", "Test@123") → “Enter a valid email”.
2. 2Add ("qa@target.dev", "") → #password-error “Password is required” and ("qa@target.dev", "wrong") → #login-error “Invalid username or password”.
3. 3Add the valid case ("qa@target.dev", "Test@123") last → #dashboard visible.
4. 4For each case open TEST_URL, fill the form, click #login-button and assert the expected message.

• Cases run through parametrisation or a data loop
• The final (valid) case reaches the dashboard
• At least 4 assertions pass

username

qa@target.dev

password

Test@123