Add rspec for output deprecation warning to non string example descri…

…ption

spec/rspec/core/example_group_spec.rb

@@ -637,6 +637,26 @@ def define_and_run_group(define_outer_example = false)
         group = RSpec.describe(Object, "my desc") { }
         expect(group.description).to eq(group.metadata[:description])
       end
+
+      it "does not output deprecation warning when description is a string" do
+        expect_no_deprecation
+        RSpec.describe.it('hoge')
+      end
+
+      it "does not output deprecation warning when description is nil" do
+        expect_no_deprecation
+        RSpec.describe.it
+      end
+
+      it "outputs deprecation warining when description is a symbol" do
+        expect_deprecation_with_call_site(__FILE__, __LINE__ + 1, /Symbol object `:symbol` as example doc string/)
+        RSpec.describe.it(:symbol)
+      end
+
+      it "outputs deprication warning when description is a hash" do
+        expect_deprecation_with_call_site(__FILE__, __LINE__ + 1, /Hash object `{"foo"=>"bar"}` as example doc string/)
+        RSpec.describe.it({ "foo" => "bar" })
+      end
     end
 
     describe '#metadata' do