1 files changed, 31 insertions, 0 deletions
diff --git a/spec/lib/gitlab/tab_width_spec.rb b/spec/lib/gitlab/tab_width_spec.rb
new file mode 100644
index 00000000000..3b5014d27e4
--- /dev/null
+++ b/spec/lib/gitlab/tab_width_spec.rb
@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+require 'fast_spec_helper'
+
+describe Gitlab::TabWidth, lib: true do
+  describe '.css_class_for_user' do
+    it 'returns default CSS class when user is nil' do
+      css_class = described_class.css_class_for_user(nil)
+
+      expect(css_class).to eq('tab-width-8')
+    end
+
+    it "returns CSS class for user's tab width", :aggregate_failures do
+      [1, 6, 12].each do |i|
+        user = double('user', tab_width: i)
+        css_class = described_class.css_class_for_user(user)
+
+        expect(css_class).to eq("tab-width-#{i}")
+      end
+    end
+
+    it 'raises if tab width is out of valid range', :aggregate_failures do
+      [0, 13, 'foo', nil].each do |i|
+        expect do
+          user = double('user', tab_width: i)
+          described_class.css_class_for_user(user)
+        end.to raise_error(ArgumentError)
+      end
+    end
+  end
+end