Fix to_s when name is a symbol #381 (#383)

* Fix to_s when name is a symbol

* Add spec for breaking case

lib/daru/dataframe.rb

@@ -1902,7 +1902,7 @@ def to_html_tbody(threshold=30)
     end
 
     def to_s
-      "#<#{self.class}#{': ' + @name if @name}(#{nrows}x#{ncols})>"
+      "#<#{self.class}#{': ' + @name.to_s if @name}(#{nrows}x#{ncols})>"
     end
 
     # Method for updating the metadata (i.e. missing value positions) of the

lib/daru/vector.rb

@@ -938,7 +938,7 @@ def to_html_tbody(threshold=30)
     end
 
     def to_s
-      "#<#{self.class}#{': ' + @name if @name}(#{size})#{':category' if category?}>"
+      "#<#{self.class}#{': ' + @name.to_s if @name}(#{size})#{':category' if category?}>"
     end
 
     # Create a summary of the Vector

spec/dataframe_spec.rb

@@ -3866,6 +3866,11 @@ def create_test(*args, &_proc)
       @data_frame.name = "Test"
       expect(@data_frame.to_s).to eq "#<Daru::DataFrame: Test(5x3)>"
     end
+
+    it 'produces a class, name, size description when the name is a symbol' do
+      @data_frame.name = :Test
+      expect(@data_frame.to_s).to eq "#<Daru::DataFrame: Test(5x3)>"
+    end
   end
 
   context '#to_json' do

spec/vector_spec.rb

@@ -1028,6 +1028,11 @@
           @v.name = "Test"
           expect(@v.to_s).to eq("#<Daru::Vector: Test(2)>")
         end
+
+        it 'produces a class, name, size description when the name is a symbol' do
+          @v.name = :Test
+          expect(@v.to_s).to eq("#<Daru::Vector: Test(2)>")
+        end
       end
 
       context "#uniq" do