Add valid login test

login_provider/test/behave/features/login.feature

@@ -8,3 +8,13 @@ Scenario: Open the login interface
     Then I wait on element "input#email" for 1000ms to be visible
     And I expect that element "input#password" is visible
     And I expect that element "input#submit" is visible
+
+Scenario: Login with a valid user
+    Given the element "input#email" is visible
+    And the element "input#password" is visible
+    And the element "input#submit" is visible
+    When I enter the "email" in the inputfield "input#email"
+    And I enter the "password" in the inputfield "input#password"
+    And I click on the button "input#submit"
+    And I wait on element "input#password" for 1000ms to not exist
+    Then I expect that element "input#email" does not exist