Only offer translation for supported languages (#23879)

spec/lib/translation_service/deepl_spec.rb

@@ -0,0 +1,100 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe TranslationService::DeepL do
+  subject(:service) { described_class.new(plan, 'my-api-key') }
+
+  let(:plan) { 'advanced' }
+
+  before do
+    stub_request(:get, 'https://api.deepl.com/v2/languages?type=source').to_return(
+      body: '[{"language":"EN","name":"English"},{"language":"UK","name":"Ukrainian"}]'
+    )
+    stub_request(:get, 'https://api.deepl.com/v2/languages?type=target').to_return(
+      body: '[{"language":"EN-GB","name":"English (British)"},{"language":"ZH","name":"Chinese"}]'
+    )
+  end
+
+  describe '#supported?' do
+    it 'supports included languages as source and target languages' do
+      expect(service.supported?('uk', 'en')).to be true
+    end
+
+    it 'supports auto-detecting source language' do
+      expect(service.supported?(nil, 'en')).to be true
+    end
+
+    it 'supports "en" and "pt" as target languages though not included in language list' do
+      expect(service.supported?('uk', 'en')).to be true
+      expect(service.supported?('uk', 'pt')).to be true
+    end
+
+    it 'does not support non-included language as target language' do
+      expect(service.supported?('uk', 'nl')).to be false
+    end
+
+    it 'does not support non-included language as source language' do
+      expect(service.supported?('da', 'en')).to be false
+    end
+  end
+
+  describe '#translate' do
+    it 'returns translation with specified source language' do
+      stub_request(:post, 'https://api.deepl.com/v2/translate')
+        .with(body: 'text=Hasta+la+vista&source_lang=ES&target_lang=en&tag_handling=html')
+        .to_return(body: '{"translations":[{"detected_source_language":"ES","text":"See you soon"}]}')
+
+      translation = service.translate('Hasta la vista', 'es', 'en')
+      expect(translation.detected_source_language).to eq 'es'
+      expect(translation.provider).to eq 'DeepL.com'
+      expect(translation.text).to eq 'See you soon'
+    end
+
+    it 'returns translation with auto-detected source language' do
+      stub_request(:post, 'https://api.deepl.com/v2/translate')
+        .with(body: 'text=Guten+Tag&source_lang&target_lang=en&tag_handling=html')
+        .to_return(body: '{"translations":[{"detected_source_language":"DE","text":"Good Morning"}]}')
+
+      translation = service.translate('Guten Tag', nil, 'en')
+      expect(translation.detected_source_language).to eq 'de'
+      expect(translation.provider).to eq 'DeepL.com'
+      expect(translation.text).to eq 'Good Morning'
+    end
+  end
+
+  describe '#languages?' do
+    it 'returns source languages' do
+      expect(service.send(:languages, 'source')).to eq ['en', 'uk', nil]
+    end
+
+    it 'returns target languages' do
+      expect(service.send(:languages, 'target')).to eq %w(en-gb zh en pt)
+    end
+  end
+
+  describe '#request' do
+    before do
+      stub_request(:any, //)
+      # rubocop:disable Lint/EmptyBlock
+      service.send(:request, :get, '/v2/languages') { |res| }
+      # rubocop:enable Lint/EmptyBlock
+    end
+
+    it 'uses paid plan base URL' do
+      expect(a_request(:get, 'https://api.deepl.com/v2/languages')).to have_been_made.once
+    end
+
+    context 'with free plan' do
+      let(:plan) { 'free' }
+
+      it 'uses free plan base URL' do
+        expect(a_request(:get, 'https://api-free.deepl.com/v2/languages')).to have_been_made.once
+      end
+    end
+
+    it 'sends API key' do
+      expect(a_request(:get, 'https://api.deepl.com/v2/languages').with(headers: { Authorization: 'DeepL-Auth-Key my-api-key' })).to have_been_made.once
+    end
+  end
+end