Fix xlsx parsing of empty cells with no formatting

lib/roo/excelx/cell/number.rb

@@ -20,14 +20,26 @@ def create_numeric(number)
           return number if Excelx::ERROR_VALUES.include?(number)
           case @format
           when /%/
-            Float(number)
+            cast_float(number)
           when /\.0/
-            Float(number)
+            cast_float(number)
           else
-            (number.include?('.') || (/\A[-+]?\d+E[-+]?\d+\z/i =~ number)) ? Float(number) : Integer(number, 10)
+            (number.include?('.') || (/\A[-+]?\d+E[-+]?\d+\z/i =~ number)) ? cast_float(number) : cast_int(number, 10)
           end
         end
 
+        def cast_float(number)
+          return 0.0 if number == ''
+
+          Float(number)
+        end
+
+        def cast_int(number, base = 10)
+          return 0 if number == ''
+
+          Integer(number, base)
+        end
+
         def formatted_value
           return @cell_value if Excelx::ERROR_VALUES.include?(@cell_value)
 

spec/lib/roo/excelx_spec.rb

@@ -616,6 +616,15 @@
     end
   end
 
+  describe 'empty value cells with no format' do
+    let(:path) { 'test/files/empty_numeric_cell.xlsx' }
+
+    it 'returns 0 for empty numeric cells' do
+      expect(subject.excelx_value(3, 2)).to eq('')
+      expect(subject.cell(3, 2)).to eq(0)
+    end
+  end
+
   describe 'opening a file with a chart sheet' do
     let(:path) { 'test/files/chart_sheet.xlsx' }
     it 'should not raise' do

test/excelx/cell/test_number.rb

@@ -15,6 +15,11 @@ def test_integer
     assert_kind_of(Integer, cell.value)
   end
 
+  def test_blank
+    cell = Roo::Excelx::Cell::Number.new '', nil, ['0'], nil, nil, nil
+    assert_kind_of(Integer, cell.value)
+  end
+
   def test_scientific_notation
     cell = Roo::Excelx::Cell::Number.new '1.2E-3', nil, ['0'], nil, nil, nil
     assert_kind_of(Float, cell.value)