diff --git a/app/controllers/access_permissions/experiments_controller.rb b/app/controllers/access_permissions/experiments_controller.rb
index 604eff459..9c57e8dfc 100644
--- a/app/controllers/access_permissions/experiments_controller.rb
+++ b/app/controllers/access_permissions/experiments_controller.rb
@@ -21,7 +21,7 @@ module AccessPermissions
 
     def update
       @experiment_member = ExperimentMember.new(current_user, @experiment, @project)
-      @experiment_member.update(permitted_update_params)
+      @experiment_member.handle_change(permitted_update_params)
 
       respond_to do |format|
         format.json do
diff --git a/app/controllers/access_permissions/my_modules_controller.rb b/app/controllers/access_permissions/my_modules_controller.rb
index 314c7f14f..43d3dfe63 100644
--- a/app/controllers/access_permissions/my_modules_controller.rb
+++ b/app/controllers/access_permissions/my_modules_controller.rb
@@ -22,7 +22,7 @@ module AccessPermissions
 
     def update
       @my_module_member = MyModuleMember.new(current_user, @my_module, @experiment, @project)
-      @my_module_member.update(permitted_update_params)
+      @my_module_member.handle_change(permitted_update_params)
 
       respond_to do |format|
         format.json do
diff --git a/app/controllers/api/v1/experiment_user_assignments_controller.rb b/app/controllers/api/v1/experiment_user_assignments_controller.rb
new file mode 100644
index 000000000..8f6f233f0
--- /dev/null
+++ b/app/controllers/api/v1/experiment_user_assignments_controller.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+
+module Api
+  module V1
+    class ExperimentUserAssignmentsController < BaseController
+      before_action :load_team
+      before_action :load_project
+      before_action :load_experiment
+      before_action :load_user_assignment, only: :show
+      before_action :load_user_assignment_for_managing, only: %i(update destroy)
+
+      def index
+        user_assignments = @experiment.user_assignments
+                                      .page(params.dig(:page, :number))
+                                      .per(params.dig(:page, :size))
+
+        render jsonapi: user_assignments,
+               each_serializer: ExperimentUserAssignmentSerializer,
+               include: :user
+      end
+
+      def show
+        render jsonapi: @user_assignment,
+               serializer: ExperimentUserAssignmentSerializer,
+               include: :user
+      end
+
+      def create
+        raise PermissionError.new(Experiment, :manage) unless can_manage_experiment?(@experiment)
+
+        user_role = UserRole.find_by_name user_assignment_params[:role]
+        experiment_member = ExperimentMember.new(current_user, @experiment, @project)
+        experiment_member.create(
+          user_role_id: user_role.id,
+          user_id: user_assignment_params[:user_id]
+        )
+        render jsonapi: experiment_member.user_project, serializer: ExperimentUserAssignmentSerializer, status: :created
+      end
+
+      def update
+        user_role = UserRole.find_by_name user_assignment_params[:role]
+        user = @user_assignment.user
+        experiment_member = ExperimentMember.new(
+          current_user,
+          @experiment,
+          @project,
+          user,
+          @user_assignment
+        )
+
+        return render body: nil, status: :no_content if @user_assignment.user_role == user_role
+
+        experiment_member.update(user_role_id: user_role.id, user_id: user.id)
+        render jsonapi: experiment_member.user_project, serializer: ExperimentUserAssignmentSerializer, status: :ok
+      end
+
+      def destroy
+        experiment_member = ExperimentMember.new(
+          current_user,
+          @experiment,
+          @project,
+          @user_assignment.user,
+          @user_assignment
+        )
+        experiment_member.destroy
+        render body: nil
+      end
+
+      private
+
+      def load_user_assignment
+        @user_assignment = @experiment.user_assignments.find(params.require(:id))
+      end
+
+      def load_user_assignment_for_managing
+        @user_assignment = @experiment.user_assignments.find(params.require(:id))
+        raise PermissionError.new(Experiment, :manage) unless can_manage_experiment?(@experiment)
+      end
+
+      def user_assignment_params
+        raise TypeError unless params.require(:data).require(:type) == 'experiment_user_assignments'
+
+        params.require(:data).require(:attributes).permit(:user_id, :role)
+      end
+    end
+  end
+end
diff --git a/app/controllers/api/v1/task_user_assignments_controller.rb b/app/controllers/api/v1/task_user_assignments_controller.rb
new file mode 100644
index 000000000..8038b7d6f
--- /dev/null
+++ b/app/controllers/api/v1/task_user_assignments_controller.rb
@@ -0,0 +1,90 @@
+# frozen_string_literal: true
+
+module Api
+  module V1
+    class TaskUserAssignmentsController < BaseController
+      before_action :load_team
+      before_action :load_project
+      before_action :load_experiment
+      before_action :load_task
+      before_action :load_user_assignment, only: :show
+      before_action :load_user_assignment_for_managing, only: %i(update destroy)
+
+      def index
+        user_assignments = @task.user_assignments
+                                .page(params.dig(:page, :number))
+                                .per(params.dig(:page, :size))
+
+        render jsonapi: user_assignments,
+               each_serializer: TaskUserAssignmentSerializer,
+               include: :user
+      end
+
+      def show
+        render jsonapi: @user_assignment,
+               serializer: TaskUserAssignmentSerializer,
+               include: :user
+      end
+
+      def create
+        raise PermissionError.new(MyModule, :read) unless can_manage_module?(@task)
+
+        user_role = UserRole.find_by_name user_assignment_params[:role]
+        my_module_member = MyModuleMember.new(current_user, @task, @experiment, @project)
+        my_module_member.create(
+          user_role_id: user_role.id,
+          user_id: user_assignment_params[:user_id]
+        )
+        render jsonapi: my_module_member.user_project, serializer: TaskUserAssignmentSerializer, status: :created
+      end
+
+      def update
+        user_role = UserRole.find_by_name user_assignment_params[:role]
+        user = @user_assignment.user
+        my_module_member = MyModuleMember.new(
+          current_user,
+          @task,
+          @experiment,
+          @project,
+          user,
+          @user_assignment
+        )
+
+        return render body: nil, status: :no_content if @user_assignment.user_role == user_role
+
+        my_module_member.update(user_role_id: user_role.id, user_id: user.id)
+        render jsonapi: my_module_member.user_project, serializer: TaskUserAssignmentSerializer, status: :ok
+      end
+
+      def destroy
+        my_module_member = MyModuleMember.new(
+          current_user,
+          @task,
+          @experiment,
+          @project,
+          @user_assignment.user,
+          @user_assignment
+        )
+        my_module_member.destroy
+        render body: nil
+      end
+
+      private
+
+      def load_user_assignment
+        @user_assignment = @task.user_assignments.find(params.require(:id))
+      end
+
+      def load_user_assignment_for_managing
+        @user_assignment = @task.user_assignments.find(params.require(:id))
+        raise PermissionError.new(MyModule, :manage) unless can_manage_module?(@task)
+      end
+
+      def user_assignment_params
+        raise TypeError unless params.require(:data).require(:type) == 'task_user_assignments'
+
+        params.require(:data).require(:attributes).permit(:user_id, :role)
+      end
+    end
+  end
+end
diff --git a/app/controllers/api/v1/user_projects_controller.rb b/app/controllers/api/v1/user_projects_controller.rb
index 1e10d47ca..c7c2fc7c6 100644
--- a/app/controllers/api/v1/user_projects_controller.rb
+++ b/app/controllers/api/v1/user_projects_controller.rb
@@ -27,22 +27,34 @@ module Api
       def create
         raise PermissionError.new(Project, :manage) unless can_manage_project?(@project)
 
-        user_project = @project.user_projects.create!(user_project_params.merge!(assigned_by: current_user))
+        # internally we reuse the same logic as for user project assignment
+        user_role = UserRole.find_by_name user_project_params[:role]
+        user = @team.users.find(user_project_params[:user_id])
 
-        render jsonapi: user_project, serializer: UserProjectSerializer, status: :created
+        project_member = ProjectMember.new(user, @project, current_user)
+        project_member.assign = true
+        project_member.user_role_id = user_role.id
+        project_member.create
+
+        render jsonapi: project_member.user_project, serializer: UserProjectSerializer, status: :created
       end
 
       def update
-        @user_project.role = user_project_params[:role]
-        return render body: nil, status: :no_content unless @user_project.changed?
+        user_role = UserRole.find_by_name user_project_params[:role]
+        project_member = ProjectMember.new(@user_project.user, @project, current_user)
 
-        @user_project.assigned_by = current_user
-        @user_project.save!
+        if project_member.user_assignment&.user_role == user_role
+          return render body: nil, status: :no_content
+        end
+
+        project_member.user_role_id = user_role.id
+        project_member.update
         render jsonapi: @user_project, serializer: UserProjectSerializer, status: :ok
       end
 
       def destroy
-        @user_project.destroy!
+        project_member = ProjectMember.new(@user_project.user, @project, current_user)
+        project_member.destroy
         render body: nil
       end
 
diff --git a/app/models/experiment_member.rb b/app/models/experiment_member.rb
index fd7d179c0..b69b4ceac 100644
--- a/app/models/experiment_member.rb
+++ b/app/models/experiment_member.rb
@@ -8,10 +8,11 @@ class ExperimentMember
               :user, :project, :user_role,
               :user_assignment
 
-  def initialize(current_user, experiment, project, user = nil)
+  def initialize(current_user, experiment, project, user = nil, user_assignment = nil)
     @experiment = experiment
     @current_user = current_user
     @project = project
+    @user_assignment = user_assignment
 
     if user
       @user = user
@@ -19,15 +20,9 @@ class ExperimentMember
     end
   end
 
-  def update(params)
-    self.user_role_id = params[:user_role_id]
-    self.user_id = params[:user_id]
-
+  def handle_change(params)
+    prepare_data(params)
     ActiveRecord::Base.transaction do
-      @user = @project.users.find(user_id)
-      @user_role = UserRole.find_by(id: user_role_id)
-      @user_assignment = UserAssignment.find_by(assignable: experiment, user: user)
-
       if destroy_role?
         user_assignment.destroy
       elsif user_assignment.present?
@@ -44,8 +39,47 @@ class ExperimentMember
     end
   end
 
+  def update(params)
+    prepare_data(params)
+
+    ActiveRecord::Base.transaction do
+      user_assignment.update!(user_role: user_role)
+      log_change_activity
+    end
+  end
+
+  def create(params)
+    prepare_data(params)
+
+    ActiveRecord::Base.transaction do
+      @user_assignment = UserAssignment.create!(
+        assignable: experiment,
+        user: user,
+        user_role: user_role,
+        assigned_by: current_user
+      )
+      log_change_activity
+    end
+  end
+
+  def destroy
+    ActiveRecord::Base.transaction do
+      user_assignment.destroy
+      log_change_activity
+    end
+  end
+
   private
 
+  def prepare_data(params)
+    self.user_role_id = params[:user_role_id]
+    self.user_id = params[:user_id]
+
+    @user = @project.users.find(user_id)
+    @user_role = UserRole.find_by(id: user_role_id)
+    @user_assignment ||= UserAssignment.find_by(assignable: experiment, user: user)
+  end
+
   def log_change_activity
     Activities::CreateActivityService.call(
       activity_type: :change_user_role_on_experiment,
diff --git a/app/models/my_module_member.rb b/app/models/my_module_member.rb
index ed17511d4..e85c73e1e 100644
--- a/app/models/my_module_member.rb
+++ b/app/models/my_module_member.rb
@@ -8,11 +8,12 @@ class MyModuleMember
               :experiment, :user, :project,
               :user_role, :user_assignment
 
-  def initialize(current_user, my_module, experiment, project, user = nil)
+  def initialize(current_user, my_module, experiment, project, user = nil , user_assignment = nil)
     @experiment = experiment
     @current_user = current_user
     @project = project
     @my_module = my_module
+    @user_assignment = user_assignment
 
     if user
       @user = user
@@ -20,15 +21,9 @@ class MyModuleMember
     end
   end
 
-  def update(params)
-    self.user_role_id = params[:user_role_id]
-    self.user_id = params[:user_id]
-
+  def handle_change(params)
+    prepare_data(params)
     ActiveRecord::Base.transaction do
-      @user = @project.users.find(user_id)
-      @user_role = UserRole.find_by(id: user_role_id)
-      @user_assignment = UserAssignment.find_by(assignable: my_module, user: user)
-
       if destroy_role?
         user_assignment.destroy
       elsif user_assignment.present?
@@ -45,8 +40,47 @@ class MyModuleMember
     end
   end
 
+  def update(params)
+    prepare_data(params)
+
+    ActiveRecord::Base.transaction do
+      user_assignment.update!(user_role: user_role)
+      log_change_activity
+    end
+  end
+
+  def create(params)
+    prepare_data(params)
+
+    ActiveRecord::Base.transaction do
+      @user_assignment = UserAssignment.create!(
+        assignable: my_module,
+        user: user,
+        user_role: user_role,
+        assigned_by: current_user
+      )
+      log_change_activity
+    end
+  end
+
+  def destroy
+    ActiveRecord::Base.transaction do
+      user_assignment.destroy
+      log_change_activity
+    end
+  end
+
   private
 
+  def prepare_data(params)
+    self.user_role_id = params[:user_role_id]
+    self.user_id = params[:user_id]
+
+    @user = @project.users.find(user_id)
+    @user_role = UserRole.find_by(id: user_role_id)
+    @user_assignment ||= UserAssignment.find_by(assignable: my_module, user: user)
+  end
+
   def log_change_activity
     Activities::CreateActivityService.call(
       activity_type: :change_user_role_on_my_module,
diff --git a/app/models/project_member.rb b/app/models/project_member.rb
index b748d1255..5698a8c70 100644
--- a/app/models/project_member.rb
+++ b/app/models/project_member.rb
@@ -4,7 +4,7 @@ class ProjectMember
   include ActiveModel::Model
 
   attr_accessor :user, :project, :assign, :user_role_id, :user_id
-  attr_reader :current_user, :user_assignment, :user_role
+  attr_reader :current_user, :user_assignment, :user_role, :user_project
 
   delegate :user_role, to: :user_assignment, allow_nil: true
 
@@ -25,7 +25,7 @@ class ProjectMember
     return unless assign
 
     ActiveRecord::Base.transaction do
-      UserProject.create!(project: @project, user: @user)
+      @user_project = UserProject.create!(project: @project, user: @user)
       @user_assignment = UserAssignment.create!(
         assignable: @project,
         user: @user,
diff --git a/app/serializers/api/v1/experiment_user_assignment_serializer.rb b/app/serializers/api/v1/experiment_user_assignment_serializer.rb
new file mode 100644
index 000000000..4c2d88625
--- /dev/null
+++ b/app/serializers/api/v1/experiment_user_assignment_serializer.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Api
+  module V1
+    class ExperimentUserAssignmentSerializer < ActiveModel::Serializer
+      type :experiment_user_assignments
+      attributes :id, :role
+
+      belongs_to :user, serializer: UserSerializer
+      belongs_to :experiment, serializer: ExperimentSerializer
+    end
+  end
+end
diff --git a/app/serializers/api/v1/task_user_assigment_serializer.rb b/app/serializers/api/v1/task_user_assigment_serializer.rb
new file mode 100644
index 000000000..37f9ae66c
--- /dev/null
+++ b/app/serializers/api/v1/task_user_assigment_serializer.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+module Api
+  module V1
+    class TaskUserAssignmentSerializer < ActiveModel::Serializer
+      type :task_user_assignments
+      attributes :id, :role
+
+      belongs_to :user, serializer: UserSerializer
+      belongs_to :task, serializer: TaskSerializer
+    end
+  end
+end
diff --git a/config/routes.rb b/config/routes.rb
index c63ece63f..5a70116d0 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -697,9 +697,11 @@ Rails.application.routes.draw do
               get 'activities', to: 'projects#activities'
               resources :reports, only: %i(index show), path: 'reports', as: :reports
               resources :experiments, only: %i(index show create update) do
+                resources :experiment_user_assignments, only: %i(index show create update)
                 resources :task_groups, only: %i(index show)
                 resources :connections, only: %i(index show)
                 resources :tasks, only: %i(index show create update) do
+                  resources :tasks_user_assignments, only: %i(index show create update)
                   resources :task_inventory_items, only: %i(index show),
                             path: 'items',
                             as: :items
diff --git a/spec/models/experiment_member_spec.rb b/spec/models/experiment_member_spec.rb
index 5a580759d..976e2aac4 100644
--- a/spec/models/experiment_member_spec.rb
+++ b/spec/models/experiment_member_spec.rb
@@ -19,7 +19,7 @@ describe ExperimentMember, type: :model do
 
   let(:subject) { described_class.new(user, experiment, project) }
 
-  describe 'update' do
+  describe '#handle_change' do
     let!(:valid_params) {
       {
         user_id: user.id,
@@ -29,7 +29,7 @@ describe ExperimentMember, type: :model do
 
     it 'creates a new user assigment when no assigment present' do
       expect {
-        subject.update(valid_params)
+        subject.handle_change(valid_params)
       }.to change(UserAssignment, :count).by(1)
     end
 
@@ -38,21 +38,101 @@ describe ExperimentMember, type: :model do
       create :user_assignment, assignable: project, user: user, user_role: normal_user_role, assigned_by: user
 
       expect {
-        subject.update(valid_params)
+        subject.handle_change(valid_params)
       }.to change(UserAssignment, :count).by(-1)
     end
 
     it 'updates the assigment user role' do
       assigment = create :user_assignment, assignable: experiment, user: user, user_role: owner_role, assigned_by: user
-      subject.update(valid_params)
+      subject.handle_change(valid_params)
       expect(assigment.reload.user_role).to eq normal_user_role
     end
 
     it 'logs a change_user_role_on_experiment activity' do
+      expect {
+        subject.handle_change(valid_params)
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_experiment'
+    end
+  end
+
+  describe '#update' do
+    let!(:experiment_user_assignment) {
+      create :user_assignment,
+             assignable: experiment,
+             user: user,
+             user_role: owner_role,
+             assigned_by: user
+    }
+
+    let!(:valid_params) {
+      {
+        user_id: user.id,
+        user_role_id: normal_user_role.id
+      }
+    }
+
+    let!(:subject) { described_class.new(user, experiment, project, user, experiment_user_assignment) }
+
+    it 'updates the assigment user role' do
+      subject.update(valid_params)
+      expect(experiment_user_assignment.reload.user_role).to eq normal_user_role
+    end
+
+    it 'logs a change_user_role_on_my_module activity' do
       expect {
         subject.update(valid_params)
       }.to change(Activity, :count).by(1)
       expect(Activity.last.type_of).to eq 'change_user_role_on_experiment'
     end
   end
+
+  describe '#destroy' do
+    let!(:experiment_user_assignment) {
+      create :user_assignment,
+             assignable: experiment,
+             user: user,
+             user_role: owner_role,
+             assigned_by: user
+    }
+
+    let!(:subject) { described_class.new(user, experiment, project, user, experiment_user_assignment) }
+
+    it 'destroys the assigment user role' do
+      expect {
+        subject.destroy
+      }.to change(UserAssignment, :count).by(-1)
+    end
+
+    it 'logs a change_user_role_on_my_module activity' do
+      expect {
+        subject.destroy
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_experiment'
+    end
+  end
+
+  describe '#create' do
+    let!(:valid_params) {
+      {
+        user_id: user.id,
+        user_role_id: normal_user_role.id
+      }
+    }
+
+    let(:subject) { described_class.new(user, experiment, project) }
+
+    it 'creates a new user assigment when no assigment present' do
+      expect {
+        subject.create(valid_params)
+      }.to change(UserAssignment, :count).by(1)
+    end
+
+    it 'logs a change_user_role_on_my_module activity' do
+      expect {
+        subject.create(valid_params)
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_experiment'
+    end
+  end
 end
diff --git a/spec/models/my_module_member_spec.rb b/spec/models/my_module_member_spec.rb
index fd6e25b04..cc9ce96c5 100644
--- a/spec/models/my_module_member_spec.rb
+++ b/spec/models/my_module_member_spec.rb
@@ -7,14 +7,18 @@ describe MyModuleMember, type: :model do
   let!(:user) { create :user }
   let!(:project) { create :project }
   let!(:user_project) { create :user_project, user: user, project: project }
-  let!(:user_assignment) { create :user_assignment, assignable: project, user: user, user_role: owner_role, assigned_by: user }
+  let!(:user_assignment) {
+    create :user_assignment,
+           assignable: project,
+           user: user,
+           user_role: owner_role,
+           assigned_by: user
+  }
   let!(:experiment) { create :experiment, project: project }
   let!(:my_module) { create :my_module, experiment: experiment }
   let(:normal_user_role) { create :normal_user_role }
 
-  let(:subject) { described_class.new(user, my_module, experiment, project) }
-
-  describe 'update' do
+  describe '#handle_change' do
     let!(:valid_params) {
       {
         user_id: user.id,
@@ -22,9 +26,11 @@ describe MyModuleMember, type: :model do
       }
     }
 
+    let(:subject) { described_class.new(user, my_module, experiment, project) }
+
     it 'creates a new user assigment when no assigment present' do
       expect {
-        subject.update(valid_params)
+        subject.handle_change(valid_params)
       }.to change(UserAssignment, :count).by(1)
     end
 
@@ -33,7 +39,7 @@ describe MyModuleMember, type: :model do
       create :user_assignment, assignable: experiment, user: user, user_role: normal_user_role, assigned_by: user
 
       expect {
-        subject.update(valid_params)
+        subject.handle_change(valid_params)
       }.to change(UserAssignment, :count).by(-1)
     end
 
@@ -42,16 +48,47 @@ describe MyModuleMember, type: :model do
       create :user_assignment, assignable: project, user: user, user_role: normal_user_role, assigned_by: user
 
       expect {
-        subject.update(valid_params)
+        subject.handle_change(valid_params)
       }.to change(UserAssignment, :count).by(-1)
     end
 
     it 'updates the assigment user role' do
       assigment = create :user_assignment, assignable: my_module, user: user, user_role: owner_role, assigned_by: user
-      subject.update(valid_params)
+      subject.handle_change(valid_params)
       expect(assigment.reload.user_role).to eq normal_user_role
     end
 
+    it 'logs a change_user_role_on_my_module activity' do
+      expect {
+        subject.handle_change(valid_params)
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_my_module'
+    end
+  end
+
+  describe '#update' do
+    let!(:my_module_user_assignment) {
+      create :user_assignment,
+             assignable: my_module,
+             user: user,
+             user_role: owner_role,
+             assigned_by: user
+    }
+
+    let!(:valid_params) {
+      {
+        user_id: user.id,
+        user_role_id: normal_user_role.id
+      }
+    }
+
+    let!(:subject) { described_class.new(user, my_module, experiment, project, user, my_module_user_assignment) }
+
+    it 'updates the assigment user role' do
+      subject.update(valid_params)
+      expect(my_module_user_assignment.reload.user_role).to eq normal_user_role
+    end
+
     it 'logs a change_user_role_on_my_module activity' do
       expect {
         subject.update(valid_params)
@@ -59,4 +96,53 @@ describe MyModuleMember, type: :model do
       expect(Activity.last.type_of).to eq 'change_user_role_on_my_module'
     end
   end
+
+  describe '#destroy' do
+    let!(:user_assignment) {
+      create :user_assignment,
+             assignable: my_module,
+             user: user,
+             user_role: owner_role,
+             assigned_by: user
+    }
+
+    let!(:subject) { described_class.new(user, my_module, experiment, project, user, user_assignment) }
+
+    it 'destroys the assigment user role' do
+      expect {
+        subject.destroy
+      }.to change(UserAssignment, :count).by(-1)
+    end
+
+    it 'logs a change_user_role_on_my_module activity' do
+      expect {
+        subject.destroy
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_my_module'
+    end
+  end
+
+  describe '#create' do
+    let!(:valid_params) {
+      {
+        user_id: user.id,
+        user_role_id: normal_user_role.id
+      }
+    }
+
+    let(:subject) { described_class.new(user, my_module, experiment, project) }
+
+    it 'creates a new user assigment when no assigment present' do
+      expect {
+        subject.create(valid_params)
+      }.to change(UserAssignment, :count).by(1)
+    end
+
+    it 'logs a change_user_role_on_my_module activity' do
+      expect {
+        subject.create(valid_params)
+      }.to change(Activity, :count).by(1)
+      expect(Activity.last.type_of).to eq 'change_user_role_on_my_module'
+    end
+  end
 end
diff --git a/spec/models/project_member_spec.rb b/spec/models/project_member_spec.rb
index 4b170062e..219acd92e 100644
--- a/spec/models/project_member_spec.rb
+++ b/spec/models/project_member_spec.rb
@@ -10,7 +10,7 @@ describe ProjectMember, type: :model do
 
   let(:subject) { described_class.new(user, project, user) }
 
-  describe 'create' do
+  describe '#create' do
     it 'create a user_assignment and user_project records' do
       subject.assign = true
       subject.user_role_id = owner_role.id
@@ -30,7 +30,7 @@ describe ProjectMember, type: :model do
     end
   end
 
-  describe 'update' do
+  describe '#update' do
     let!(:user_project) { create :user_project, user: user, project: project }
     let!(:user_assignment) {
       create :user_assignment,
@@ -55,7 +55,7 @@ describe ProjectMember, type: :model do
     end
   end
 
-  describe 'destroy' do
+  describe '#destroy' do
     let!(:user_two) { create :user }
     let!(:user_project_two) { create :user_project, user: user_two, project: project }
     let!(:user_assignment_two) {