discourse/spec/services/flag_sockpuppets_spec.rb

# frozen_string_literal: true

RSpec.describe SpamRule::FlagSockpuppets do
  fab!(:user1) { Fabricate(:user, ip_address: "182.189.119.174") }
  fab!(:post1) { Fabricate(:post, user: user1, topic: Fabricate(:topic, user: user1)) }

  describe "#perform" do
    subject(:perform) { rule.perform }

    let(:rule) { described_class.new(post1) }

    it "does nothing if flag_sockpuppets is disabled" do
      SiteSetting.flag_sockpuppets = false
      rule.expects(:reply_is_from_sockpuppet?).never
      rule.expects(:flag_sockpuppet_users).never
      expect(perform).to eq(false)
    end

    context "when flag_sockpuppets is enabled" do
      before { SiteSetting.flag_sockpuppets = true }

      it "flags posts when it should" do
        rule.expects(:reply_is_from_sockpuppet?).returns(:true)
        rule.expects(:flag_sockpuppet_users).once
        expect(perform).to eq(true)
      end

      it "doesn't flag posts when it shouldn't" do
        rule.expects(:reply_is_from_sockpuppet?).returns(false)
        rule.expects(:flag_sockpuppet_users).never
        expect(perform).to eq(false)
      end
    end
  end

  describe "#reply_is_from_sockpuppet?" do
    it "is false for the first post in a topic" do
      expect(described_class.new(post1).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is false if users have different IP addresses" do
      post2 =
        Fabricate(:post, user: Fabricate(:user, ip_address: "182.189.199.199"), topic: post1.topic)
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is true if users have the same IP address and are new" do
      post2 =
        Fabricate(:post, user: Fabricate(:user, ip_address: user1.ip_address), topic: post1.topic)
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(true)
    end

    it "is false if the ip address is allowlisted" do
      ScreenedIpAddress.stubs(:is_allowed?).with(user1.ip_address).returns(true)
      post2 =
        Fabricate(:post, user: Fabricate(:user, ip_address: user1.ip_address), topic: post1.topic)
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is false if reply and first post are from the same user" do
      post2 = Fabricate(:post, user: user1, topic: post1.topic)
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is false if first post user is staff" do
      staff1 = Fabricate(:admin, ip_address: "182.189.119.174")
      staff_post1 = Fabricate(:post, user: staff1, topic: Fabricate(:topic, user: staff1))
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:user, ip_address: staff1.ip_address),
          topic: staff_post1.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is false if second post user is staff" do
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:moderator, ip_address: user1.ip_address),
          topic: post1.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is false if both users are staff" do
      staff1 = Fabricate(:moderator, ip_address: "182.189.119.174")
      staff_post1 = Fabricate(:post, user: staff1, topic: Fabricate(:topic, user: staff1))
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:admin, ip_address: staff1.ip_address),
          topic: staff_post1.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is true if first post user was created over 24 hours ago and has trust level higher than 0" do
      old_user =
        Fabricate(
          :user,
          ip_address: "182.189.119.174",
          created_at: 25.hours.ago,
          trust_level: TrustLevel[1],
        )
      first_post = Fabricate(:post, user: old_user, topic: Fabricate(:topic, user: old_user))
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:user, ip_address: old_user.ip_address),
          topic: first_post.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(true)
    end

    it "is false if second post user was created over 24 hours ago and has trust level higher than 0" do
      post2 =
        Fabricate(
          :post,
          user:
            Fabricate(
              :user,
              ip_address: user1.ip_address,
              created_at: 25.hours.ago,
              trust_level: TrustLevel[1],
            ),
          topic: post1.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end

    it "is true if first post user was created less that 24 hours ago and has trust level higher than 0" do
      new_user =
        Fabricate(
          :user,
          ip_address: "182.189.119.174",
          created_at: 1.hour.ago,
          trust_level: TrustLevel[1],
        )
      first_post = Fabricate(:post, user: new_user, topic: Fabricate(:topic, user: new_user))
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:user, ip_address: new_user.ip_address),
          topic: first_post.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(true)
    end

    it "is true if second user was created less that 24 hours ago and has trust level higher than 0" do
      post2 =
        Fabricate(
          :post,
          user:
            Fabricate(
              :user,
              ip_address: user1.ip_address,
              created_at: 23.hours.ago,
              trust_level: TrustLevel[1],
            ),
          topic: post1.topic,
        )
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(true)
    end

    # A weird case
    it "is false when user is nil on first post" do
      post1.user = nil
      post1.save!
      post2 = Fabricate(:post, user: Fabricate(:user), topic: post1.topic)
      expect(described_class.new(post2).reply_is_from_sockpuppet?).to eq(false)
    end
  end

  describe "#flag_sockpuppet_users" do
    fab!(:post2) do
      Fabricate(:post, user: Fabricate(:user, ip_address: user1.ip_address), topic: post1.topic)
    end
    let(:system) { Discourse.system_user }
    let(:spam) { PostActionType.types[:spam] }

    it "flags post and first post if both users are new" do
      described_class.new(post2).flag_sockpuppet_users

      expect(PostAction.where(user: system, post: post1, post_action_type_id: spam).exists?).to eq(
        true,
      )
      expect(PostAction.where(user: system, post: post2, post_action_type_id: spam).exists?).to eq(
        true,
      )
    end

    it "doesn't flag the first post more than once" do
      described_class.new(post2).flag_sockpuppet_users

      expect(PostAction.where(user: system, post: post2, post_action_type_id: spam).exists?).to eq(
        true,
      )
      expect(PostAction.where(post: post2, post_action_type_id: spam).count).to eq(1)
    end

    it "doesn't flag the first post if the user is not new" do
      old_user =
        Fabricate(
          :user,
          ip_address: "182.189.119.174",
          created_at: 25.hours.ago,
          trust_level: TrustLevel[1],
        )
      first_post = Fabricate(:post, user: old_user, topic: Fabricate(:topic, user: old_user))
      post2 =
        Fabricate(
          :post,
          user: Fabricate(:user, ip_address: old_user.ip_address),
          topic: first_post.topic,
        )

      described_class.new(post2).flag_sockpuppet_users

      expect(PostAction.where(user: system, post: post2, post_action_type_id: spam).exists?).to eq(
        true,
      )
      expect(
        PostAction.where(user: system, post: first_post, post_action_type_id: spam).exists?,
      ).to eq(false)
    end

    it "doesn't create a flag if user is nil on first post" do
      post1.user_id = nil
      post1.save
      described_class.new(post2).flag_sockpuppet_users

      expect(PostAction.where(user: system, post: post2, post_action_type_id: spam).exists?).to eq(
        true,
      )
      expect(PostAction.where(user: system, post: post1, post_action_type_id: spam).exists?).to eq(
        false,
      )
    end

    it "doesn't flag the first post if it was already rejected by staff before" do
      flagged_post =
        Fabricate(
          :reviewable_flagged_post,
          target: post1,
          status: Reviewable.statuses[:rejected],
          target_created_by: post1.user,
        )

      described_class.new(post2).perform

      expect(flagged_post.reload).to be_rejected
    end

    it "doesn't flag the post if another post of the same user was rejected by staff before" do
      another_post = Fabricate(:post, user: user1)
      flagged_post =
        Fabricate(
          :reviewable_flagged_post,
          target: another_post,
          status: Reviewable.statuses[:rejected],
          target_created_by: another_post.user,
        )

      described_class.new(post2).perform

      expect(ReviewableFlaggedPost.where(target_created_by: user1).count).to eq(1)
    end
  end
end