Fix missing merged cells.

Merge cell info for all but the last merged cell was missing from XML output.

2 files changed, 3 insertions, 1 deletions

diff --git a/lib/axlsx/workbook/worksheet/worksheet.rb b/lib/axlsx/workbook/worksheet/worksheet.rb
index 7d26b088..7aa38866 100644
--- a/lib/axlsx/workbook/worksheet/worksheet.rb
+++ b/lib/axlsx/workbook/worksheet/worksheet.rb
@@ -403,7 +403,7 @@ module Axlsx
       @rows.each_with_index { |row, index| row.to_xml_string(index, str) }
       str.concat '</sheetData>'
       str.concat "<autoFilter ref='%s'></autoFilter>" % @auto_filter if @auto_filter
-      str.concat "<mergeCells count='%s'>%s</mergeCells>" % [@merged_cells.size, @merged_cells.reduce('') { |memo, obj| "<mergeCell ref='%s'></mergeCell>" % obj } ] unless @merged_cells.empty?
+      str.concat "<mergeCells count='%s'>%s</mergeCells>" % [@merged_cells.size, @merged_cells.reduce('') { |memo, obj| memo += "<mergeCell ref='%s'></mergeCell>" % obj } ] unless @merged_cells.empty?
       page_margins.to_xml_string(str) if @page_margins
       str.concat "<drawing r:id='rId1'></drawing>" if @drawing
       unless @tables.empty?
diff --git a/test/workbook/worksheet/tc_worksheet.rb b/test/workbook/worksheet/tc_worksheet.rb
index 67b11d3c..320561b3 100644
--- a/test/workbook/worksheet/tc_worksheet.rb
+++ b/test/workbook/worksheet/tc_worksheet.rb
@@ -207,8 +207,10 @@ class TestWorksheet < Test::Unit::TestCase
   def test_to_xml_string_merge_cells
     @ws.add_row [1, "two"]
     @ws.merge_cells "A1:D1"
+    @ws.merge_cells "E1:F1"
     doc = Nokogiri::XML(@ws.to_xml_string)
     assert_equal(doc.xpath('//xmlns:worksheet/xmlns:mergeCells/xmlns:mergeCell[@ref="A1:D1"]').size, 1)
+    assert_equal(doc.xpath('//xmlns:worksheet/xmlns:mergeCells/xmlns:mergeCell[@ref="E1:F1"]').size, 1)
   end
 
   def test_to_xml_string_page_margins