1 files changed, 53 insertions, 0 deletions
diff --git a/spec/lib/gitlab/i18n/pluralization_spec.rb b/spec/lib/gitlab/i18n/pluralization_spec.rb
new file mode 100644
index 00000000000..857562d549c
--- /dev/null
+++ b/spec/lib/gitlab/i18n/pluralization_spec.rb
@@ -0,0 +1,53 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+require 'rspec-parameterized'
+require 'gettext_i18n_rails'
+
+RSpec.describe Gitlab::I18n::Pluralization, feature_category: :internationalization do
+  describe '.call' do
+    subject(:rule) { described_class.call(1) }
+
+    context 'with available locales' do
+      around do |example|
+        Gitlab::I18n.with_locale(locale, &example)
+      end
+
+      where(:locale) do
+        Gitlab::I18n.available_locales
+      end
+
+      with_them do
+        it 'supports pluralization' do
+          expect(rule).not_to be_nil
+        end
+      end
+
+      context 'with missing rules' do
+        let(:locale) { "pl_PL" }
+
+        before do
+          stub_const("#{described_class}::MAP", described_class::MAP.except(locale))
+        end
+
+        it 'raises an ArgumentError' do
+          expect { rule }.to raise_error(ArgumentError,
+            /Missing pluralization rule for locale "#{locale}"/
+          )
+        end
+      end
+    end
+  end
+
+  describe '.install_on' do
+    let(:mod) { Module.new }
+
+    before do
+      described_class.install_on(mod)
+    end
+
+    it 'adds pluralisation_rule method' do
+      expect(mod.pluralisation_rule).to eq(described_class)
+    end
+  end
+end