Add specs for FollowLimitValidator (mastodon#9655)

Author: ysksn

spec/validators/follow_limit_validator_spec.rb

@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe FollowLimitValidator, type: :validator do
+  describe '#validate' do
+    before do
+      allow_any_instance_of(described_class).to receive(:limit_reached?).with(account) do
+        limit_reached
+      end
+
+      described_class.new.validate(follow)
+    end
+
+    let(:follow)  { double(account: account, errors: errors) }
+    let(:errors)  { double(add: nil) }
+    let(:account) { double(nil?: _nil, local?: local, following_count: 0, followers_count: 0) }
+    let(:_nil)    { true }
+    let(:local)   { false }
+
+    context 'follow.account.nil? || !follow.account.local?' do
+      let(:_nil)    { true }
+
+      it 'not calls errors.add' do
+        expect(errors).not_to have_received(:add).with(:base, any_args)
+      end
+    end
+
+    context '!(follow.account.nil? || !follow.account.local?)' do
+      let(:_nil)    { false }
+      let(:local)   { true }
+
+      context 'limit_reached?' do
+        let(:limit_reached) { true }
+
+        it 'calls errors.add' do
+          expect(errors).to have_received(:add)
+            .with(:base, I18n.t('users.follow_limit_reached', limit: FollowLimitValidator::LIMIT))
+        end
+      end
+
+      context '!limit_reached?' do
+        let(:limit_reached) { false }
+
+        it 'not calls errors.add' do
+          expect(errors).not_to have_received(:add).with(:base, any_args)
+        end
+      end
+    end
+  end
+end