diff --git a/.moban.d/custom_README.rst.jj2 b/.moban.d/custom_README.rst.jj2
index 92002e5..42b8805 100644
--- a/.moban.d/custom_README.rst.jj2
+++ b/.moban.d/custom_README.rst.jj2
@@ -1,7 +1,8 @@
 {%extends 'README.rst.jj2' %}
 
 {%block description%}
-**{{name}}** is a tiny wrapper library to write data in xlsx and xlsm fromat using libxlsxwriter. You are likely to use it with `pyexcel <https://github.com/pyexcel/pyexcel>`__.
+**{{name}}** is a tiny wrapper library to write data in xlsx and xlsm format
+using libxlsxwriter. You are likely to use it with `pyexcel <https://github.com/pyexcel/pyexcel>`__.
 {%endblock%}
 
 
@@ -61,3 +62,6 @@ Let's assume we have data as the following.
 
 {%block read_from_memory_via_pyexcel %}
 {%endblock%}
+
+{% block pyexcel_write_to_memory%}
+{% endblock %}
\ No newline at end of file
diff --git a/README.rst b/README.rst
index ca67d4f..204fe86 100644
--- a/README.rst
+++ b/README.rst
@@ -33,7 +33,8 @@ pyexcel-libxlsxw - Let you focus on data, instead of xlsx format
 .. image:: https://readthedocs.org/projects/pyexcel-libxlsxw/badge/?version=latest
    :target: http://pyexcel-libxlsxw.readthedocs.org/en/latest/
 
-**pyexcel-libxlsxw** is a tiny wrapper library to write data in xlsx and xlsm fromat using libxlsxwriter. You are likely to use it with `pyexcel <https://github.com/pyexcel/pyexcel>`__.
+**pyexcel-libxlsxw** is a tiny wrapper library to write data in xlsx and xlsm format
+using libxlsxwriter. You are likely to use it with `pyexcel <https://github.com/pyexcel/pyexcel>`__.
 
 Support the project
 ================================================================================
@@ -198,23 +199,6 @@ Here is the sample code:
     >>> sheet.save_as("another_file.xlsx")
 
 
-Writing to a StringIO instance
-********************************************************************************
-
-You need to pass a StringIO instance to Writer:
-
-.. code-block:: python
-
-    >>> data = [
-    ...     [1, 2, 3],
-    ...     [4, 5, 6]
-    ... ]
-    >>> io = StringIO()
-    >>> sheet = pe.Sheet(data)
-    >>> io = sheet.save_to_memory("xlsx", io)
-    >>> # then do something with io
-    >>> # In reality, you might give it to your http response
-    >>> # object for downloading
 
 
 License
diff --git a/tests/base.py b/tests/base.py
index 73ea2bf..7250e47 100644
--- a/tests/base.py
+++ b/tests/base.py
@@ -5,17 +5,6 @@
 from nose.tools import eq_
 
 
-def create_sample_file1(file):
-    data = ["a", "b", "c", "d", "e", "f", "g", "h", "i", "j", 1.1, 1]
-    table = []
-    table.append(data[:4])
-    table.append(data[4:8])
-    table.append(data[8:12])
-    pyexcel.save_as(
-        array=table, dest_file_name=file, library="pyexcel-libxlsxw"
-    )
-
-
 class PyexcelHatWriterBase:
     """
     Abstract functional test for hat writers
diff --git a/tests/test_stringio.py b/tests/test_stringio.py
index a5502fa..ef43fc8 100644
--- a/tests/test_stringio.py
+++ b/tests/test_stringio.py
@@ -1,6 +1,5 @@
 import pyexcel
 
-
 from nose.tools import eq_
 
 
diff --git a/tests/test_writer.py b/tests/test_writer.py
index 956db41..b40d2fa 100644
--- a/tests/test_writer.py
+++ b/tests/test_writer.py
@@ -1,4 +1,5 @@
 import os
+from datetime import date, time, datetime
 
 from base import PyexcelWriterBase, PyexcelHatWriterBase
 from pyexcel_xls import get_data
@@ -8,13 +9,29 @@
 
 
 class TestNativeXLWriter:
+    def setUp(self):
+        self.testfile = "xlwriter.xlsx"
+
     def test_write_book(self):
         self.content = {
             "Sheet1": [[1, 1, 1, 1], [2, 2, 2, 2], [3, 3, 3, 3]],
             "Sheet2": [[4, 4, 4, 4], [5, 5, 5, 5], [6, 6, 6, 6]],
             "Sheet3": [[u"X", u"Y", u"Z"], [1, 4, 7], [2, 5, 8], [3, 6, 9]],
         }
-        self.testfile = "xlwriter.xlsx"
+        writer = xlsx.XLSXWriter(self.testfile, "xlsx")
+        writer.write(self.content)
+        writer.close()
+        content = get_data(self.testfile)
+        for key in content.keys():
+            content[key] = list(content[key])
+        eq_(content, self.content)
+
+    def test_write_dates(self):
+        self.content = {
+            "date": [[date(2020, 10, 11)]],
+            "time": [[time(11, 22, 11)]],
+            "datetime": [[datetime(2020, 11, 11, 12, 12, 12)]],
+        }
         writer = xlsx.XLSXWriter(self.testfile, "xlsx")
         writer.write(self.content)
         writer.close()