test: cover I18nBackendTest, test_lookup_returns_nil_for_unknown_key

test/test_i18n_backend.rb

@@ -0,0 +1,53 @@
+require 'minitest/autorun'
+require 'prism'
+require 'tmpdir'
+
+class I18nBackendTest < Minitest::Test
+  def setup
+    @backend = Prism::I18n::Backend.new
+  end
+
+  def test_lookup_returns_nil_for_unknown_key
+    assert_nil @backend.lookup(:en, 'missing.key')
+  end
+
+  def test_store_and_lookup_nested_key
+    @backend.store_translations(:en, 'posts' => { 'title' => 'Title', 'body' => 'Body' })
+    assert_equal 'Title', @backend.lookup(:en, 'posts.title')
+    assert_equal 'Body', @backend.lookup(:en, :'posts.body')
+  end
+
+  def test_store_translations_deep_merges_instead_of_replacing
+    @backend.store_translations(:en, 'posts' => { 'title' => 'Title' })
+    @backend.store_translations(:en, 'posts' => { 'body' => 'Body' })
+    assert_equal 'Title', @backend.lookup(:en, 'posts.title')
+    assert_equal 'Body', @backend.lookup(:en, 'posts.body')
+  end
+
+  def test_locales_lists_every_stored_locale
+    @backend.store_translations(:en, 'hello' => 'Hello')
+    @backend.store_translations(:pl, 'hello' => 'Czesc')
+    assert_equal [:en, :pl], @backend.locales.sort
+  end
+
+  def test_lookup_returns_nil_when_key_path_hits_a_non_hash
+    @backend.store_translations(:en, 'hello' => 'Hello')
+    assert_nil @backend.lookup(:en, 'hello.nested')
+  end
+
+  def test_load_file_reads_json_and_uses_basename_as_locale
+    Dir.mktmpdir do |dir|
+      path = File.join(dir, 'en.json')
+      File.write(path, '{"greeting": "Hi %{name}"}')
+      locale = @backend.load_file(path)
+      assert_equal :en, locale
+      assert_equal 'Hi %{name}', @backend.lookup(:en, 'greeting')
+    end
+  end
+
+  def test_clear_removes_all_translations
+    @backend.store_translations(:en, 'hello' => 'Hello')
+    @backend.clear!
+    assert_empty @backend.locales
+  end
+end

test/test_i18n_controller.rb

@@ -0,0 +1,85 @@
+require 'minitest/autorun'
+require 'prism'
+require 'support'
+
+class GreetingsController < Prism::Controller
+  def show
+    html(t('hello'))
+  end
+
+  def remember
+    session[:locale] = params['locale']
+    html(t('hello'))
+  end
+
+  def stamp
+    html(l(Time.utc(2026, 3, 5, 8, 30, 0)))
+  end
+end
+
+class GreetingsApp < Prism::Application
+  enable_sessions secret: 'i18n-controller-test-secret'
+
+  get '/greet', to: 'greetings#show'
+  get '/greet/remember', to: 'greetings#remember'
+  get '/greet/stamp', to: 'greetings#stamp'
+end
+
+class I18nControllerTest < Minitest::Test
+  include TestSupport
+
+  def setup
+    Prism::I18n.reset!
+    Prism::I18n.store_translations(:en, 'hello' => 'Hello')
+    Prism::I18n.store_translations(:pl, 'hello' => 'Czesc')
+  end
+
+  def teardown
+    Prism::I18n.reset!
+  end
+
+  def call(method, path, **opts)
+    GreetingsApp.call(env_for(method, path, **opts))
+  end
+
+  def test_defaults_to_default_locale_with_no_hints
+    _, _, body = call('GET', '/greet')
+    assert_equal 'Hello', body.join
+  end
+
+  def test_locale_query_param_overrides_default
+    _, _, body = call('GET', '/greet?locale=pl')
+    assert_equal 'Czesc', body.join
+  end
+
+  def test_unknown_locale_query_param_is_ignored
+    _, _, body = call('GET', '/greet?locale=de')
+    assert_equal 'Hello', body.join
+  end
+
+  def test_accept_language_header_is_used_when_no_param_given
+    _, _, body = call('GET', '/greet', headers: { 'Accept-Language' => 'pl,en;q=0.5' })
+    assert_equal 'Czesc', body.join
+  end
+
+  def test_locale_param_wins_over_accept_language_header
+    _, _, body = call('GET', '/greet?locale=en', headers: { 'Accept-Language' => 'pl' })
+    assert_equal 'Hello', body.join
+  end
+
+  def test_session_locale_is_sticky_across_requests
+    status, headers, body = call('GET', '/greet/remember?locale=pl')
+    assert_equal 200, status
+    assert_equal 'Czesc', body.join
+    line = headers['Set-Cookie'].split("\n").find { |c| c.start_with?('prism.session=') }
+    cookie = line.split(';').first
+
+    _, _, body = call('GET', '/greet', cookies: cookie)
+    assert_equal 'Czesc', body.join
+  end
+
+  def test_localize_helper_formats_time_in_view
+    _, _, body = call('GET', '/greet/stamp')
+    assert_equal '2026-03-05 08:30:00', body.join
+  end
+end