Add policy param to POST /api/v1/push/subscriptions (#16040)

With possible values `all`, `followed`, `follower`, and `none`,
control from whom notifications will generate a Web Push alert

spec/models/web/push_subscription_spec.rb

@@ -1,16 +1,94 @@
 require 'rails_helper'
 
 RSpec.describe Web::PushSubscription, type: :model do
-  let(:alerts) { { mention: true, reblog: false, follow: true, follow_request: false, favourite: true } }
-  let(:push_subscription) { Web::PushSubscription.new(data: { alerts: alerts }) }
+  let(:account) { Fabricate(:account) }
+
+  let(:policy) { 'all' }
+
+  let(:data) do
+    {
+      policy: policy,
+
+      alerts: {
+        mention: true,
+        reblog: false,
+        follow: true,
+        follow_request: false,
+        favourite: true,
+      },
+    }
+  end
+
+  subject { described_class.new(data: data) }
 
   describe '#pushable?' do
-    it 'obeys alert settings' do
-      expect(push_subscription.send(:pushable?, Notification.new(activity_type: 'Mention'))).to eq true
-      expect(push_subscription.send(:pushable?, Notification.new(activity_type: 'Status'))).to eq false
-      expect(push_subscription.send(:pushable?, Notification.new(activity_type: 'Follow'))).to eq true
-      expect(push_subscription.send(:pushable?, Notification.new(activity_type: 'FollowRequest'))).to eq false
-      expect(push_subscription.send(:pushable?, Notification.new(activity_type: 'Favourite'))).to eq true
+    let(:notification_type) { :mention }
+    let(:notification) { Fabricate(:notification, account: account, type: notification_type) }
+
+    %i(mention reblog follow follow_request favourite).each do |type|
+      context "when notification is a #{type}" do
+        let(:notification_type) { type }
+
+        it "returns boolean corresonding to alert setting" do
+          expect(subject.pushable?(notification)).to eq data[:alerts][type]
+        end
+      end
+    end
+
+    context 'when policy is all' do
+      let(:policy) { 'all' }
+
+      it 'returns true' do
+        expect(subject.pushable?(notification)).to eq true
+      end
+    end
+
+    context 'when policy is none' do
+      let(:policy) { 'none' }
+
+      it 'returns false' do
+        expect(subject.pushable?(notification)).to eq false
+      end
+    end
+
+    context 'when policy is followed' do
+      let(:policy) { 'followed' }
+
+      context 'and notification is from someone you follow' do
+        before do
+          account.follow!(notification.from_account)
+        end
+
+        it 'returns true' do
+          expect(subject.pushable?(notification)).to eq true
+        end
+      end
+
+      context 'and notification is not from someone you follow' do
+        it 'returns false' do
+          expect(subject.pushable?(notification)).to eq false
+        end
+      end
+    end
+
+    context 'when policy is follower' do
+      let(:policy) { 'follower' }
+
+      context 'and notification is from someone who follows you' do
+        before do
+          notification.from_account.follow!(account)
+        end
+
+        it 'returns true' do
+          expect(subject.pushable?(notification)).to eq true
+        end
+      end
+
+      context 'and notification is not from someone who follows you' do
+        it 'returns false' do
+          expect(subject.pushable?(notification)).to eq false
+        end
+      end
     end
   end
 end