Fix tests / code to work with frozen string literals

1 files changed, 11 insertions, 11 deletions

diff --git a/lib/axlsx/workbook/worksheet/pivot_table.rb b/lib/axlsx/workbook/worksheet/pivot_table.rb
index 8c6cb83e..e97b8119 100644
--- a/lib/axlsx/workbook/worksheet/pivot_table.rb
+++ b/lib/axlsx/workbook/worksheet/pivot_table.rb
@@ -186,13 +186,13 @@ module Axlsx
     # Serializes the object
     # @param [String] str
     # @return [String]
-    def to_xml_string(str = '')
+    def to_xml_string(str = +'')
       str << '<?xml version="1.0" encoding="UTF-8"?>'
 
-      str << ('<pivotTableDefinition xmlns="' << XML_NS << '" name="' << name << '" cacheId="' << cache_definition.cache_id.to_s << '"' << (data.size <= 1 ? ' dataOnRows="1"' : '') << ' applyNumberFormats="0" applyBorderFormats="0" applyFontFormats="0" applyPatternFormats="0" applyAlignmentFormats="0" applyWidthHeightFormats="1" dataCaption="Data" showMultipleLabel="0" showMemberPropertyTips="0" useAutoFormatting="1" indent="0" compact="0" compactData="0" gridDropZones="1" multipleFieldFilters="0">')
+      str << (+'<pivotTableDefinition xmlns="' << XML_NS << '" name="' << name << '" cacheId="' << cache_definition.cache_id.to_s << '"' << (data.size <= 1 ? ' dataOnRows="1"' : '') << ' applyNumberFormats="0" applyBorderFormats="0" applyFontFormats="0" applyPatternFormats="0" applyAlignmentFormats="0" applyWidthHeightFormats="1" dataCaption="Data" showMultipleLabel="0" showMemberPropertyTips="0" useAutoFormatting="1" indent="0" compact="0" compactData="0" gridDropZones="1" multipleFieldFilters="0">')
 
-      str << ('<location firstDataCol="1" firstDataRow="1" firstHeaderRow="1" ref="' << ref << '"/>')
-      str << ('<pivotFields count="' << header_cells_count.to_s << '">')
+      str << (+'<location firstDataCol="1" firstDataRow="1" firstHeaderRow="1" ref="' << ref << '"/>')
+      str << (+'<pivotFields count="' << header_cells_count.to_s << '">')
 
       header_cell_values.each do |cell_value|
         subtotal = !no_subtotals_on_headers.include?(cell_value)
@@ -205,12 +205,12 @@ module Axlsx
         str << '<rowFields count="1"><field x="-2"/></rowFields>'
         str << '<rowItems count="2"><i><x/></i> <i i="1"><x v="1"/></i></rowItems>'
       else
-        str << ('<rowFields count="' << rows.size.to_s << '">')
+        str << (+'<rowFields count="' << rows.size.to_s << '">')
         rows.each do |row_value|
-          str << ('<field x="' << header_index_of(row_value).to_s << '"/>')
+          str << (+'<field x="' << header_index_of(row_value).to_s << '"/>')
         end
         str << '</rowFields>'
-        str << ('<rowItems count="' << rows.size.to_s << '">')
+        str << (+'<rowItems count="' << rows.size.to_s << '">')
         rows.size.times do |i|
           str << '<i/>'
         end
@@ -229,16 +229,16 @@ module Axlsx
           str << '<colItems count="1"><i/></colItems>'
         end
       else
-        str << ('<colFields count="' << columns.size.to_s << '">')
+        str << (+'<colFields count="' << columns.size.to_s << '">')
         columns.each do |column_value|
-          str << ('<field x="' << header_index_of(column_value).to_s << '"/>')
+          str << (+'<field x="' << header_index_of(column_value).to_s << '"/>')
         end
         str << '</colFields>'
       end
       unless pages.empty?
-        str << ('<pageFields count="' << pages.size.to_s << '">')
+        str << (+'<pageFields count="' << pages.size.to_s << '">')
         pages.each do |page_value|
-          str << ('<pageField fld="' << header_index_of(page_value).to_s << '"/>')
+          str << (+'<pageField fld="' << header_index_of(page_value).to_s << '"/>')
         end
         str << '</pageFields>'
       end