Add tests for I18n.exists? freedom patch

lib/freedom_patches/i18n_fallbacks.rb

@@ -1,3 +1,5 @@
+# This should be used until https://github.com/svenfuchs/i18n/pull/326 is merged into the I18n gem.
+
 module I18n
   module Backend
     module Fallbacks

spec/helpers/i18n_fallbacks_spec.rb

@@ -0,0 +1,52 @@
+require 'spec_helper'
+
+describe 'freedom patch for I18n::Backend::Fallbacks' do
+  before do
+    SiteSetting.default_locale = 'de'
+    I18n.locale = :de
+
+    store_translations(:en, :foo => 'Foo in :en', :bar => 'Bar in :en')
+    store_translations(:de, :bar => 'Bar in :de')
+    store_translations(:'de-AT', :baz => 'Baz in :de-AT')
+  end
+
+  def store_translations(locale, data)
+    I18n.backend.store_translations(locale, data)
+  end
+
+  describe '#exists?' do
+    it 'returns true when a key is given that exists in the default locale' do
+      expect(I18n.exists?(:bar)).to be true
+    end
+
+    it 'returns true when a key is given that exists in a fallback locale of the default locale' do
+      expect(I18n.exists?(:foo)).to be true
+    end
+
+    it 'returns false when a non-existing key is given' do
+      expect(I18n.exists?(:bogus)).to be false
+    end
+
+    it 'returns true when an existing key and an existing locale is given' do
+      expect(I18n.exists?(:foo, :en)).to be true
+      expect(I18n.exists?(:bar, :de)).to be true
+      expect(I18n.exists?(:baz, :'de-AT')).to be true
+    end
+
+    it 'returns false when a non-existing key and an existing locale is given' do
+      expect(I18n.exists?(:bogus, :en)).to be false
+      expect(I18n.exists?(:bogus, :de)).to be false
+      expect(I18n.exists?(:bogus, :'de-AT')).to be false
+    end
+
+    it 'returns true when a key is given which is missing from the given locale and exists in a fallback locale' do
+      expect(I18n.exists?(:foo, :de)).to be true
+      expect(I18n.exists?(:foo, :'de-AT')).to be true
+    end
+
+    it 'returns true when a key is given which is missing from the given locale and all its fallback locales' do
+      expect(I18n.exists?(:baz, :de)).to be false
+      expect(I18n.exists?(:bogus, :'de-AT')).to be false
+    end
+  end
+end