Add remove from followers api (#16864)

* Add followed_by? to account_interactions

* Add RemoveFromFollowersService

* Fix AccountBatch to use RemoveFromFollowersService

* Add remove from followers API

spec/controllers/api/v1/accounts_controller_spec.rb

@@ -168,6 +168,26 @@ RSpec.describe Api::V1::AccountsController, type: :controller do
     it_behaves_like 'forbidden for wrong scope', 'read:accounts'
   end
 
+  describe 'POST #remove_from_followers' do
+    let(:scopes) { 'write:follows' }
+    let(:other_account) { Fabricate(:user, email: 'bob@example.com', account: Fabricate(:account, username: 'bob')).account }
+
+    before do
+      other_account.follow!(user.account)
+      post :remove_from_followers, params: { id: other_account.id }
+    end
+
+    it 'returns http success' do
+      expect(response).to have_http_status(200)
+    end
+
+    it 'removes the followed relation between user and target user' do
+      expect(user.account.followed_by?(other_account)).to be false
+    end
+
+    it_behaves_like 'forbidden for wrong scope', 'read:accounts'
+  end
+
   describe 'POST #block' do
     let(:scopes) { 'write:blocks' }
     let(:other_account) { Fabricate(:user, email: 'bob@example.com', account: Fabricate(:account, username: 'bob')).account }

spec/models/concerns/account_interactions_spec.rb

@@ -360,6 +360,23 @@ describe AccountInteractions do
     end
   end
 
+  describe '#followed_by?' do
+    subject { account.followed_by?(target_account) }
+
+    context 'followed by target_account' do
+      it 'returns true' do
+        account.passive_relationships.create(account: target_account)
+        is_expected.to be true
+      end
+    end
+
+    context 'not followed by target_account' do
+      it 'returns false' do
+        is_expected.to be false
+      end
+    end
+  end
+
   describe '#blocking?' do
     subject { account.blocking?(target_account) }
 

spec/services/remove_from_follwers_service_spec.rb

@@ -0,0 +1,38 @@
+require 'rails_helper'
+
+RSpec.describe RemoveFromFollowersService, type: :service do
+  let(:bob) { Fabricate(:account, username: 'bob') }
+
+  subject { RemoveFromFollowersService.new }
+
+  describe 'local' do
+    let(:sender) { Fabricate(:account, username: 'alice') }
+ 
+    before do
+      Follow.create(account: sender, target_account: bob)
+      subject.call(bob, sender)
+    end
+
+    it 'does not create follow relation' do
+      expect(bob.followed_by?(sender)).to be false
+    end
+  end
+
+  describe 'remote ActivityPub' do
+    let(:sender) { Fabricate(:account, username: 'alice', domain: 'example.com', protocol: :activitypub, inbox_url: 'http://example.com/inbox') }
+
+    before do
+      Follow.create(account: sender, target_account: bob)
+      stub_request(:post, sender.inbox_url).to_return(status: 200)
+      subject.call(bob, sender)
+    end
+
+    it 'does not create follow relation' do
+      expect(bob.followed_by?(sender)).to be false
+    end
+
+    it 'sends a reject activity' do
+      expect(a_request(:post, sender.inbox_url)).to have_been_made.once
+    end
+  end
+end