add spec to user enqueuer, add user page queue depth to watermark limit

app/lib/domain/fa/user_enqueuer.rb

@@ -46,10 +46,17 @@ class Domain::Fa::UserEnqueuer
       return SpecUtil.enqueued_jobs(Domain::Fa::Job::UserFollowsJob).count
     end
 
-    GoodJob::Job.where(
-      queue_name: "fa_user_follows",
-      finished_at: nil,
-      performed_at: nil,
-    ).count
+    [
+      GoodJob::Job.where(
+        queue_name: "fa_user_follows",
+        finished_at: nil,
+        performed_at: nil,
+      ).count,
+      GoodJob::Job.where(
+        queue_name: "fa_user_page",
+        finished_at: nil,
+        performed_at: nil,
+      ).count,
+    ].max
   end
 end

spec/lib/domain/fa/user_enquerer_spec.rb

@@ -0,0 +1,37 @@
+describe Domain::Fa::UserEnqueuer do
+  it "works" do
+    ActiveJob::Base.queue_adapter = :test
+    users = 7.times.map do
+      SpecUtil.create_domain_fa_user
+    end
+
+    enqueuer = Domain::Fa::UserEnqueuer.new(
+      start_at: 0,
+      high_water_mark: 5,
+      low_water_mark: 3,
+    )
+
+    get_enqueued_users = proc do
+      SpecUtil.enqueued_jobs(Domain::Fa::Job::UserFollowsJob).map do |job|
+        job[:args][0][:user]
+      end
+    end
+
+    enqueuer.run_once
+    expect(get_enqueued_users.call).to eq(users[0...5])
+    SpecUtil.shift_jobs(Domain::Fa::Job::UserFollowsJob)
+
+    enqueuer.run_once
+    expect(get_enqueued_users.call).to eq(users[1...5])
+    SpecUtil.shift_jobs(Domain::Fa::Job::UserFollowsJob)
+
+    enqueuer.run_once
+    expect(get_enqueued_users.call).to eq(users[2...7])
+    SpecUtil.shift_jobs(Domain::Fa::Job::UserFollowsJob, 3)
+
+    expect do
+      enqueuer.run_once
+    end.to raise_exception(StopIteration)
+    expect(get_enqueued_users.call).to eq(users[5...7])
+  end
+end