1 files changed, 91 insertions, 0 deletions
diff --git a/spec/lib/gitlab/resource_events/assignment_event_recorder_spec.rb b/spec/lib/gitlab/resource_events/assignment_event_recorder_spec.rb
new file mode 100644
index 00000000000..b15f95dbd9c
--- /dev/null
+++ b/spec/lib/gitlab/resource_events/assignment_event_recorder_spec.rb
@@ -0,0 +1,91 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::ResourceEvents::AssignmentEventRecorder, feature_category: :value_stream_management do
+  using RSpec::Parameterized::TableSyntax
+
+  let_it_be(:user1) { create(:user) }
+  let_it_be(:user2) { create(:user) }
+  let_it_be(:user3) { create(:user) }
+
+  let_it_be_with_refind(:issue_with_two_assignees) { create(:issue, assignees: [user1, user2]) }
+  let_it_be_with_refind(:mr_with_no_assignees) { create(:merge_request) }
+  let_it_be_with_refind(:mr_with_one_assignee) { create(:merge_request, assignee: [user3]) }
+
+  let(:parent_records) do
+    {
+      issue_with_two_assignees: issue_with_two_assignees,
+      mr_with_no_assignees: mr_with_no_assignees,
+      mr_with_one_assignee: mr_with_one_assignee
+    }
+  end
+
+  let(:user_records) do
+    {
+      user1: user1,
+      user2: user2,
+      user3: user3
+    }
+  end
+
+  where(:parent, :new_assignees, :assignee_history) do
+    :issue_with_two_assignees | [:user1, :user2, :user3] | [[:user3, :add]]
+    :issue_with_two_assignees | [:user1, :user3]         | [[:user2, :remove], [:user3, :add]]
+    :issue_with_two_assignees | [:user1]                 | [[:user2, :remove]]
+    :issue_with_two_assignees | []                       | [[:user1, :remove], [:user2, :remove]]
+    :mr_with_no_assignees     | [:user1]                 | [[:user1, :add]]
+    :mr_with_no_assignees     | []                       | []
+    :mr_with_one_assignee     | [:user3]                 | []
+    :mr_with_one_assignee     | [:user1]                 | [[:user3, :remove], [:user1, :add]]
+  end
+
+  with_them do
+    it 'records the assignment history corrently' do
+      parent_record = parent_records[parent]
+      old_assignees = parent_record.assignees.to_a
+      parent_record.assignees = new_assignees.map { |user_variable_name| user_records[user_variable_name] }
+
+      described_class.new(parent: parent_record, old_assignees: old_assignees).record
+
+      expected_records = assignee_history.map do |user_variable_name, action|
+        have_attributes({
+          user_id: user_records[user_variable_name].id,
+          action: action.to_s
+        })
+      end
+
+      expect(parent_record.assignment_events).to match_array(expected_records)
+    end
+  end
+
+  context 'when batching' do
+    it 'invokes multiple insert queries' do
+      stub_const('Gitlab::ResourceEvents::AssignmentEventRecorder::BATCH_SIZE', 1)
+
+      expect(ResourceEvents::MergeRequestAssignmentEvent).to receive(:insert_all).twice
+
+      described_class.new(parent: mr_with_one_assignee, old_assignees: [user1]).record # 1 assignment, 1 unassignment
+    end
+  end
+
+  context 'when duplicated old assignees were given' do
+    it 'deduplicates the records' do
+      expect do
+        described_class.new(parent: mr_with_one_assignee, old_assignees: [user3, user2, user2]).record
+      end.to change { ResourceEvents::MergeRequestAssignmentEvent.count }.by(1)
+    end
+  end
+
+  context 'when the record_issue_and_mr_assignee_events FF is off' do
+    before do
+      stub_feature_flags(record_issue_and_mr_assignee_events: false)
+    end
+
+    it 'does nothing' do
+      expect do
+        described_class.new(parent: mr_with_one_assignee, old_assignees: [user2, user3]).record
+      end.not_to change { mr_with_one_assignee.assignment_events.count }
+    end
+  end
+end