7 files changed, 13 insertions, 15 deletions
diff --git a/examples/example.rb b/examples/example.rb
index 1ef2ab24..609096b5 100644
--- a/examples/example.rb
+++ b/examples/example.rb
@@ -9,7 +9,7 @@ if ARGV.size == 0 || ARGV.include?("1")
       p = Axlsx::Package.new
       p.workbook.add_worksheet do |sheet|
         sheet.add_row ["First", "Second", "Third"]
-        sheet.add_row [1, 2, 3]
+        sheet.add_row [1, 2, Time.now]
       end
       p.serialize("example1.xlsx")
 end
diff --git a/lib/axlsx/stylesheet/styles.rb b/lib/axlsx/stylesheet/styles.rb
index 6b64fb30..de5835dd 100644
--- a/lib/axlsx/stylesheet/styles.rb
+++ b/lib/axlsx/stylesheet/styles.rb
@@ -286,6 +286,8 @@ module Axlsx
       @cellXfs = SimpleTypedList.new Xf, "cellXfs"
       @cellXfs << Xf.new(:borderId=>0, :xfId=>0, :numFmtId=>0, :fontId=>0, :fillId=>0)
       @cellXfs << Xf.new(:borderId=>1, :xfId=>0, :numFmtId=>0, :fontId=>0, :fillId=>0)
+      # default date formatting
+      @cellXfs << Xf.new(:borderId=>0, :xfId=>0, :numFmtId=>14, :fontId=>0, :fillId=>0)
       @cellXfs.lock
 
       @dxfs = SimpleTypedList.new(Xf, "dxfs"); @dxfs.lock
diff --git a/lib/axlsx/util/constants.rb b/lib/axlsx/util/constants.rb
index 50dd6f27..4f1cb561 100644
--- a/lib/axlsx/util/constants.rb
+++ b/lib/axlsx/util/constants.rb
@@ -199,6 +199,9 @@ module Axlsx
   # cellXfs id for thin borders around the cell
   STYLE_THIN_BORDER = 1
 
+  # cellXfs id for default date styling
+  STYLE_DATE = 2
+
   # error messages RestrictionValidor
   ERR_RESTRICTION = "Invalid Data: %s. %s must be one of %s." 
 
diff --git a/lib/axlsx/workbook/worksheet/cell.rb b/lib/axlsx/workbook/worksheet/cell.rb
index 1b1b60cc..a9b4a704 100644
--- a/lib/axlsx/workbook/worksheet/cell.rb
+++ b/lib/axlsx/workbook/worksheet/cell.rb
@@ -169,6 +169,7 @@ module Axlsx
     def cast_value(v)
       if (@type == :time && v.is_a?(Time)) || (@type == :time && v.respond_to?(:to_time))
         v = v.respond_to?(:to_time) ? v.to_time : v
+        self.style = STYLE_DATE if self.style == 0
         # Using hardcoded offsets here as some operating systems will not except a 'negative' offset from the ruby epoc.
         # (1970)
         epoc1900 = -2209021200 #Time.local(1900, 1, 1) 
diff --git a/test/rels/tc_relationships.rb b/test/rels/tc_relationships.rb
index fb3795c3..c6b4860d 100644
--- a/test/rels/tc_relationships.rb
+++ b/test/rels/tc_relationships.rb
@@ -3,7 +3,6 @@ require 'axlsx.rb'
 
 class TestRelationships < Test::Unit::TestCase
 
-
   def test_valid_document
     @rels = Axlsx::Relationships.new
     schema = Nokogiri::XML::Schema(File.open(Axlsx::RELS_XSD))
diff --git a/test/stylesheet/tc_styles.rb b/test/stylesheet/tc_styles.rb
index 0c9b3fba..15020608 100644
--- a/test/stylesheet/tc_styles.rb
+++ b/test/stylesheet/tc_styles.rb
@@ -49,16 +49,4 @@ class TestStyles < Test::Unit::TestCase
 
   end
 
-
-  #:numFmts, :fonts, :fills, :borders, :cellStyleXfs, :cellXfs, :dxfs, :tableStyles
-  def test_ensure_locking
-    assert_equal(@styles.numFmts.locked_at, 2, "numFmts should be locked at 2")
-    assert_equal(@styles.fonts.locked_at, 1, "fonts should be locked at 1" )
-    assert_equal(@styles.fills.locked_at, 2, "fills should be locked at 2" )
-    assert_equal(@styles.borders.locked_at, 2, "borders should be locked at two" )
-    assert_equal(@styles.cellStyleXfs.locked_at, 1, "cellStyleXfs should be locked at two" )
-    assert_equal(@styles.cellXfs.locked_at, 2, "cellXfs should be locked at 2" )
-    assert_equal(@styles.dxfs.locked_at, 0, "dxfs should be locked at 0" )
-    assert_equal(@styles.tableStyles.locked_at, 0, "tableStyles should be locked at 0" )
-  end
 end
diff --git a/test/workbook/worksheet/tc_cell.rb b/test/workbook/worksheet/tc_cell.rb
index 6cc9a2c8..58c76bbc 100644
--- a/test/workbook/worksheet/tc_cell.rb
+++ b/test/workbook/worksheet/tc_cell.rb
@@ -18,6 +18,11 @@ class TestCell < Test::Unit::TestCase
     assert_equal(@c.value, 1.0, "type option is applied and value is casted")
   end
 
+  def test_style_date_data
+    c = Axlsx::Cell.new(@c.row, Time.now)
+    assert_equal(Axlsx::STYLE_DATE, c.style)
+  end
+
   def test_index
     assert_equal(@c.index, @row.cells.index(@c))
   end
@@ -31,7 +36,7 @@ class TestCell < Test::Unit::TestCase
   end
 
   def test_style
-    assert_raise(ArgumentError, "must reject invalid style indexes") { @c.style=3 }
+    assert_raise(ArgumentError, "must reject invalid style indexes") { @[email protected] }
     assert_nothing_raised("must allow valid style index changes") {@c.style=1} 
     assert_equal(@c.style, 1)
   end