Fix zero-padded numbers for Excelx

Fixes roo-rb#139 for Excelx documents.

lib/roo/excelx.rb

@@ -194,6 +194,13 @@ def excelx_value(row, col, sheet = nil)
       safe_send(sheet_for(sheet).cells[key], :cell_value)
     end
 
+    # returns the internal value of an excelx cell
+    # Note: this is only available within the Excelx class
+    def formatted_value(row, col, sheet = nil)
+      key = normalize(row, col)
+      safe_send(sheet_for(sheet).cells[key], :formatted_value)
+    end
+
     # returns the internal format of an excel cell
     def excelx_format(row, col, sheet = nil)
       key = normalize(row, col)

lib/roo/excelx/cell/number.rb

@@ -34,6 +34,8 @@ def formatted_value
           formatter = formats[@format]
           if formatter.is_a? Proc
             formatter.call(@cell_value)
+          elsif zero_padded_number?
+            "%0#{@format.size}d"% @cell_value
           else
             Kernel.format(formatter, @cell_value)
           end
@@ -80,6 +82,12 @@ def formats
             '@' => proc { |number| number }
           }
         end
+
+        private
+
+        def zero_padded_number?
+          @format[/0+/] == @format
+        end
       end
     end
   end

spec/lib/roo/excelx_spec.rb

@@ -283,6 +283,16 @@
     end
   end
 
+  describe '#formatted_value' do
+    context 'contains zero-padded numbers' do
+      let(:path) { 'test/files/zero-padded-number.xlsx' }
+
+      it 'returns a zero-padded number' do
+        expect(subject.formatted_value(4, 1)).to eq '05010'
+      end
+    end
+  end
+
   describe '#excelx_format' do
     let(:path) { 'test/files/style.xlsx' }