Unit tests for date handling. Because pyshp doctests are currently …

…failing, and because the README is getting very unwieldy, I've used the Python 2.1+ stdlib 'unittest' framework. It would be nice to start building a robust unit testing suite anyway!

tests/date_tests.py

@@ -0,0 +1,41 @@
+"""
+Unit tests for Pythonic `datetime.date` object handling.
+"""
+
+import unittest
+import datetime
+try:
+    from StringIO import StringIO
+except ImportError:
+    from io import BytesIO as StringIO
+
+import shapefile
+
+
+class TestDateHandling(unittest.TestCase):
+
+    def testDateReadWrite(self):
+        """Round-trip read and write Python `date` as value for 'D' field"""
+        today = datetime.date.today()
+
+        # Write a one-field, one-record shp to memory; use `date` obj as value
+        writer = shapefile.Writer()
+        writer.field('DATEFIELD', 'D', 8)
+        writer.null()
+        writer.record(today)
+        shp, shx, dbf = StringIO(), StringIO(), StringIO()
+        writer.save(shp=shp, shx=shx, dbf=dbf)
+
+        # Read our in-memory shp to verify that Reader gives us a `date` obj
+        reader = shapefile.Reader(shp=shp, shx=shx, dbf=dbf)
+        self.assertEqual(reader.fields[-1][1], 'D')
+        self.assertEqual(len(reader.records()), 1)
+        record = reader.record(0)
+        d = record[0]
+        self.assertTrue(isinstance(d, datetime.date),
+                        "Expected a `date` object back from Reader (we got a %s)" % type(d))
+        self.assertEqual(d, today)
+
+
+if __name__ == '__main__':
+    unittest.main()