Im currently working on a small project and i decided to play around with Behat/Mink a little and i came across my first problem i can not solve alone.
I have this feature and it is working as expected
Scenario: Create Customer
Given I am on "/login"
When I fill in "username" with "testuser"
And I fill in "password" with "123"
And I press "Login"
And I follow "Customers"
And I follow "Create"
Then I should be on "/customer/new"
And I fill in "email" with "test@test.de"
And I press "Save"
Then I should be on "/customer/"
And I should see "test@test.de"
When i press on "Save" the project then checks, if the email already exists. If it does it just redirects to /customer. How can i assert, that a text is only once (not twice or more) on my page?