Fix tests / code to work with frozen string literals

1 files changed, 10 insertions, 10 deletions

diff --git a/lib/axlsx/drawing/axis.rb b/lib/axlsx/drawing/axis.rb
index 6ee2b9f4..38e57da5 100644
--- a/lib/axlsx/drawing/axis.rb
+++ b/lib/axlsx/drawing/axis.rb
@@ -148,11 +148,11 @@ module Axlsx
     # Serializes the object
     # @param [String] str
     # @return [String]
-    def to_xml_string(str = '')
-      str << ('<c:axId val="' << @id.to_s << '"/>')
+    def to_xml_string(str = +'')
+      str << (+'<c:axId val="' << @id.to_s << '"/>')
       @scaling.to_xml_string str
-      str << ('<c:delete val="' << @delete.to_s << '"/>')
-      str << ('<c:axPos val="' << @ax_pos.to_s << '"/>')
+      str << (+'<c:delete val="' << @delete.to_s << '"/>')
+      str << (+'<c:axPos val="' << @ax_pos.to_s << '"/>')
       str << '<c:majorGridlines>'
       # TODO: shape properties need to be extracted into a class
       if gridlines == false
@@ -167,21 +167,21 @@ module Axlsx
       # Need to set sourceLinked to 0 if we're setting a format code on this row
       # otherwise it will never take, as it will always prefer the 'General' formatting
       # of the cells themselves
-      str << ('<c:numFmt formatCode="' << @format_code << '" sourceLinked="' << (@format_code.eql?('General') ? '1' : '0') << '"/>')
+      str << (+'<c:numFmt formatCode="' << @format_code << '" sourceLinked="' << (@format_code.eql?('General') ? '1' : '0') << '"/>')
       str << '<c:majorTickMark val="none"/>'
       str << '<c:minorTickMark val="none"/>'
-      str << ('<c:tickLblPos val="' << @tick_lbl_pos.to_s << '"/>')
+      str << (+'<c:tickLblPos val="' << @tick_lbl_pos.to_s << '"/>')
       # TODO: this is also being used for series colors
       # time to extract this into a class spPr - Shape Properties
       if @color
         str << '<c:spPr><a:ln><a:solidFill>'
-        str << ('<a:srgbClr val="' << @color << '"/>')
+        str << (+'<a:srgbClr val="' << @color << '"/>')
         str << '</a:solidFill></a:ln></c:spPr>'
       end
       # some potential value in implementing this in full. Very detailed!
-      str << ('<c:txPr><a:bodyPr rot="' << @label_rotation.to_s << '"/><a:lstStyle/><a:p><a:pPr><a:defRPr/></a:pPr><a:endParaRPr/></a:p></c:txPr>')
-      str << ('<c:crossAx val="' << @cross_axis.id.to_s << '"/>')
-      str << ('<c:crosses val="' << @crosses.to_s << '"/>')
+      str << (+'<c:txPr><a:bodyPr rot="' << @label_rotation.to_s << '"/><a:lstStyle/><a:p><a:pPr><a:defRPr/></a:pPr><a:endParaRPr/></a:p></c:txPr>')
+      str << (+'<c:crossAx val="' << @cross_axis.id.to_s << '"/>')
+      str << (+'<c:crosses val="' << @crosses.to_s << '"/>')
     end
   end
 end