test: adds spec to bring class methods over 90% coverage

Test in line 32 fails, not sure why

Author: julitrows

spec/injectable/class_methods_spec.rb

@@ -0,0 +1,45 @@
+describe Injectable::ClassMethods do
+  describe '#simple_class_attribute' do
+    subject(:klass) do
+      Class.new do
+        include Injectable
+
+        def self.singleton_class?
+          true
+        end
+
+        class_eval do
+          simple_class_attribute :flag
+        end
+
+        def call
+          'jarl'
+        end
+      end
+    end
+
+    it 'defines instance reader delegating to singleton reader when singleton_class?' do
+      klass.flag = 'on'
+      expect(klass.flag).to eq('on')
+    end
+
+    it 'passes the singleton class attribute value to the instances' do
+      klass.flag = 'on'
+      instance = klass.new
+      expect(instance.flag).to eq('on')
+    end
+
+    it 'allows to modify attribute value on the instance', skip: 'Failing, need to investigate' do
+      instance = klass.new
+      instance.instance_variable_set('@flag', 'local')
+      expect(instance.flag).to eq('local')
+    end
+
+    it 'does not pass instance values up to the singleton class value' do
+      klass.flag = 'on'
+      instance = klass.new
+      instance.instance_variable_set('@flag', 'local')
+      expect(klass.flag).to eq 'on'
+    end
+  end
+end