1 files changed, 101 insertions, 0 deletions
diff --git a/spec/services/issuable/callbacks/milestone_spec.rb b/spec/services/issuable/callbacks/milestone_spec.rb
new file mode 100644
index 00000000000..085ed029a6c
--- /dev/null
+++ b/spec/services/issuable/callbacks/milestone_spec.rb
@@ -0,0 +1,101 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Issuable::Callbacks::Milestone, feature_category: :team_planning do
+  let_it_be(:group) { create(:group) }
+  let_it_be(:project) { create(:project, :private, group: group) }
+  let_it_be(:project_milestone) { create(:milestone, project: project) }
+  let_it_be(:group_milestone) { create(:milestone, group: group) }
+  let_it_be(:reporter) do
+    create(:user).tap { |u| project.add_reporter(u) }
+  end
+
+  let(:issuable) { build(:issue, project: project) }
+  let(:current_user) { reporter }
+  let(:params) { { milestone_id: project_milestone.id } }
+  let(:callback) { described_class.new(issuable: issuable, current_user: current_user, params: params) }
+
+  describe '#after_initialize' do
+    it "sets the issuable's milestone" do
+      expect { callback.after_initialize }.to change { issuable.milestone }.from(nil).to(project_milestone)
+    end
+
+    context 'when assigning a group milestone' do
+      let(:params) { { milestone_id: group_milestone.id } }
+
+      it "sets the issuable's milestone" do
+        expect { callback.after_initialize }.to change { issuable.milestone }.from(nil).to(group_milestone)
+      end
+    end
+
+    context 'when assigning a group milestone outside the project ancestors' do
+      let(:another_group_milestone) { create(:milestone, group: create(:group)) }
+      let(:params) { { milestone_id: another_group_milestone.id } }
+
+      it "does not change the issuable's milestone" do
+        expect { callback.after_initialize }.not_to change { issuable.milestone }
+      end
+    end
+
+    context 'when user is not allowed to set issuable metadata' do
+      let(:current_user) { create(:user) }
+
+      it "does not change the issuable's milestone" do
+        expect { callback.after_initialize }.not_to change { issuable.milestone }
+      end
+    end
+
+    context 'when unsetting a milestone' do
+      let(:issuable) { create(:issue, project: project, milestone: project_milestone) }
+
+      context 'when milestone_id is nil' do
+        let(:params) { { milestone_id: nil } }
+
+        it "unsets the issuable's milestone" do
+          expect { callback.after_initialize }.to change { issuable.milestone }.from(project_milestone).to(nil)
+        end
+      end
+
+      context 'when milestone_id is an empty string' do
+        let(:params) { { milestone_id: '' } }
+
+        it "unsets the issuable's milestone" do
+          expect { callback.after_initialize }.to change { issuable.milestone }.from(project_milestone).to(nil)
+        end
+      end
+
+      context 'when milestone_id is 0' do
+        let(:params) { { milestone_id: '0' } }
+
+        it "unsets the issuable's milestone" do
+          expect { callback.after_initialize }.to change { issuable.milestone }.from(project_milestone).to(nil)
+        end
+      end
+
+      context "when milestone_id is '0'" do
+        let(:params) { { milestone_id: 0 } }
+
+        it "unsets the issuable's milestone" do
+          expect { callback.after_initialize }.to change { issuable.milestone }.from(project_milestone).to(nil)
+        end
+      end
+
+      context 'when milestone_id is not given' do
+        let(:params) { {} }
+
+        it "does not unset the issuable's milestone" do
+          expect { callback.after_initialize }.not_to change { issuable.milestone }
+        end
+      end
+
+      context 'when new type does not support milestones' do
+        let(:params) { { excluded_in_new_type: true } }
+
+        it "unsets the issuable's milestone" do
+          expect { callback.after_initialize }.to change { issuable.milestone }.from(project_milestone).to(nil)
+        end
+      end
+    end
+  end
+end