Increase Behat test coverage for locale features

Switching to different locales is covered. And the correct working of
the stepup-locale cookie is proven

tests/Functional/Features/Context/WebContext.php

@@ -309,6 +309,14 @@ public function iShouldSeeANameIDWithEmailAddress($emailAddress){
         }
     }
 
+    /**
+     * @Given I have :language set as my stepup-locale cookie value
+     */
+    public function iHaveSetAsMyPreference($language)
+    {
+        $this->minkContext->getSession()->setCookie('stepup_locale', $language);
+    }
+
     private function receiveResponse()
     {
         $samlResponse = $this->minkContext->getSession()->getPage()->find('css', 'input[name="SAMLResponse"]');

tests/Functional/Features/registration.feature

@@ -13,6 +13,30 @@ Feature: When an user needs to register for a new token
     And the SAML Response should contain element "StatusCode" with attribute "Value" with attribute value "urn:oasis:names:tc:SAML:2.0:status:Success"
     And the SAML Response should contain element "NameID" with value containing "[email protected]"
 
+  Scenario: The user is presented the page in his preferred language based on stepup-locale cookie NL
+    Given I have "nl" set as my stepup-locale cookie value
+    And I send a registration request request to "https://azure-mfa.stepup.example.com/saml/sso"
+    Then I should see "Registratie"
+
+  Scenario: The user is presented the page in his preferred language based on stepup-locale cookie EN
+    Given I have "en" set as my stepup-locale cookie value
+    And I send a registration request request to "https://azure-mfa.stepup.example.com/saml/sso"
+    Then I should see "Registration"
+
+  Scenario: When a user is registering a new token and switches back and forth from English to Dutch language during registration
+    Given I send a registration request request to "https://azure-mfa.stepup.example.com/saml/sso"
+    Then I should see "Registration"
+    And I follow "NL"
+    Then I should see "Registratie"
+    And I follow "EN"
+    Then I should see "Registration"
+    And I fill in "Email address" with "[email protected]"
+    When I press "Submit"
+    And I press "Submit-success"
+    Then I should be on "https://azure-mfa.stepup.example.com/saml/sso_return"
+    And the SAML Response should contain element "StatusCode" with attribute "Value" with attribute value "urn:oasis:names:tc:SAML:2.0:status:Success"
+    And the SAML Response should contain element "NameID" with value containing "[email protected]"
+
   Scenario: When a user is registering a new token, authentication at Azure MFA fails
     Given I send a registration request request to "https://azure-mfa.stepup.example.com/saml/sso"
     Then I should see "Registration"