diff --git a/message/tests/behat/group_conversation.feature b/message/tests/behat/group_conversation.feature
new file mode 100644
index 00000000000..c6fce937555
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+++ b/message/tests/behat/group_conversation.feature
@@ -0,0 +1,54 @@
+@core @core_message @javascript
+Feature: Create conversations for course's groups
+  In order to manage a course group in a course
+  As a user
+  I need to be able to ensure group conversations reflect the memberships of course groups
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category | groupmode |
+      | Course 1 | C1        | 0        | 1         |
+    And the following "users" exist:
+      | username | firstname | lastname | email                |
+      | teacher1 | Teacher   | 1        | teacher1@example.com |
+      | student0 | Student   | 0        | student0@example.com |
+      | student1 | Student   | 1        | student1@example.com |
+      | student2 | Student   | 2        | student2@example.com |
+      | student3 | Student   | 3        | student3@example.com |
+      | student4 | Student   | 4        | student4@example.com |
+    And the following "course enrolments" exist:
+      | user     | course | role |
+      | teacher1 | C1     | editingteacher |
+      | student0 | C1     | student |
+      | student1 | C1     | student |
+      | student2 | C1     | student |
+      | student3 | C1     | student |
+      | student4 | C1     | student |
+    And the following "groups" exist:
+      | name    | course | idnumber | enablemessaging |
+      | Group 1 | C1     | G1       | 1               |
+      | Group 2 | C1     | G2       | 1               |
+      | Group 3 | C1     | G3       | 0               |
+    And the following "group members" exist:
+      | user     | group |
+      | teacher1 | G1 |
+      | student0 | G1 |
+      | student1 | G1 |
+      | student2 | G1 |
+      | student3 | G1 |
+      | teacher1 | G2 |
+      | teacher1 | G3 |
+      | student0 | G3 |
+
+  Scenario: Group conversations are restricted to members
+    Given I log in as "teacher1"
+    Then I open messaging
+    And "Group 1" "group_message" should exist
+    And "Group 2" "group_message" should exist
+    And "Group 3" "group_message" should not exist
+    And I log out
+    And I log in as "student1"
+    And I open messaging
+    And "Group 1" "group_message" should exist
+    And "Group 2" "group_message" should not exist
+    And "Group 3" "group_message" should not exist
diff --git a/theme/boost/tests/behat/group_conversation.feature b/theme/boost/tests/behat/group_conversation.feature
new file mode 100644
index 00000000000..8738b9b1206
--- /dev/null
+++ b/theme/boost/tests/behat/group_conversation.feature
@@ -0,0 +1,90 @@
+@javascript @theme_boost
+Feature: Create conversations for course's groups in Boost theme
+  In order to manage a course group in a course
+  As a user
+  I need to be able to ensure group conversations reflect the memberships of course groups
+
+  Background:
+    Given the following "courses" exist:
+      | fullname | shortname | category | groupmode |
+      | Course 1 | C1        | 0        | 1         |
+    And the following "users" exist:
+      | username | firstname | lastname | email                |
+      | teacher1 | Teacher   | 1        | teacher1@example.com |
+      | student0 | Student   | 0        | student0@example.com |
+      | student1 | Student   | 1        | student1@example.com |
+      | student2 | Student   | 2        | student2@example.com |
+      | student3 | Student   | 3        | student3@example.com |
+      | student4 | Student   | 4        | student4@example.com |
+    And the following "course enrolments" exist:
+      | user     | course | role |
+      | teacher1 | C1     | editingteacher |
+      | student0 | C1     | student |
+      | student1 | C1     | student |
+      | student2 | C1     | student |
+      | student3 | C1     | student |
+      | student4 | C1     | student |
+    And the following "groups" exist:
+      | name    | course | idnumber | enablemessaging |
+      | Group 1 | C1     | G1       | 1               |
+      | Group 2 | C1     | G2       | 1               |
+      | Group 3 | C1     | G3       | 0               |
+    And the following "group members" exist:
+      | user     | group |
+      | teacher1 | G1 |
+      | student0 | G1 |
+      | student1 | G1 |
+      | student2 | G1 |
+      | student3 | G1 |
+      | teacher1 | G2 |
+      | teacher1 | G3 |
+      | student0 | G3 |
+
+  Scenario: View group conversation's participants numbers
+    Given I log in as "teacher1"
+    Then I open messaging
+    And I select "Group 1" conversation in messaging
+    And "5 participants" "group_message_header" should exist
+    And I go back in "view-conversation" message drawer
+    And I select "Group 2" conversation in messaging
+    And "1 participants" "group_message_header" should exist
+
+  Scenario: View group conversation's participants list
+    Given I log in as "teacher1"
+    Then I open messaging
+    # Check Group 1 participants list.
+    And I select "Group 1" conversation in messaging
+    And I open messaging information
+    And "Teacher 1" "group_message_member" should not exist
+    And "Student 0" "group_message_member" should exist
+    And "Student 1" "group_message_member" should exist
+    And "Student 2" "group_message_member" should exist
+    And "Student 3" "group_message_member" should exist
+    And "Student 4" "group_message_member" should not exist
+    And I go back in "group-info-content-container" message drawer
+    And I go back in "view-conversation" message drawer
+    # Check Group 2 participants list.
+    And I select "Group 2" conversation in messaging
+    And I open messaging information
+    And "Teacher 1" "group_message_member" should not exist
+    And "No participants" "group_message_member" should exist
+    And "Student 4" "group_message_member" should not exist
+
+  Scenario: Check group conversation members are synced when a new group member is added
+    Given I log in as "teacher1"
+    Then I am on "Course 1" course homepage
+    And I navigate to "Users > Groups" in current page administration
+    And I add "Student 4 (student4@example.com)" user to "Group 1" group members
+    And I add "Student 4 (student4@example.com)" user to "Group 2" group members
+    And I open messaging
+    And I select "Group 1" conversation in messaging
+    And "6 participants" "group_message_header" should exist
+    And I open messaging information
+    And "Student 4" "group_message_member" should exist
+    And I go back in "group-info-content-container" message drawer
+    And I go back in "view-conversation" message drawer
+    And I select "Group 2" conversation in messaging
+    And "2 participants" "group_message_header" should exist
+    And I open messaging information
+    And "No participants" "group_message_member" should not exist
+    And "Student 4" "group_message_member" should exist