MDL-82898 @enrol_self: Behat to test student enrolment using key

enrol/self/tests/behat/self_enrolment.feature

@@ -9,6 +9,7 @@ Feature: Users can auto-enrol themself in courses where self enrolment is allowe
       | username | firstname | lastname | email |
       | teacher1 | Teacher | 1 | teacher1@example.com |
       | student1 | Student | 1 | student1@example.com |
+      | student2 | Student | 2 | student2@example.com |
     And the following "courses" exist:
       | fullname | shortname | format |
       | Course 1 | C1 | topics |
@@ -82,6 +83,16 @@ Feature: Users can auto-enrol themself in courses where self enrolment is allowe
     Then I should see "New section"
     And I should not see "Enrolment options"
     And I should not see "Enrol me in this course"
+    And I am on the "Course 1" course page logged in as student2
+    And I set the following fields to these values:
+      | Enrolment key | moodle_rules |
+    And I press "Enrol me"
+    And I am on the "Course 1" course page logged in as teacher1
+    And I navigate to course participants
+    And the following should exist in the "participants" table:
+      | First name | Email address        | Roles   | Groups    |
+      | Student 1  | student1@example.com | Student | Group 1   |
+      | Student 2  | student2@example.com | Student | No groups |
 
   @javascript
   Scenario: Edit a self-enrolled user's enrolment from the course participants page