Rewrote form widget tests as proper unittests.

This is preparation for landing the template-based widget rendering
patch and goes a long way to making these tests more useful for future
development. The old doctest heritage is strong here.

tests/forms_tests/widget_tests/test_splitdatetimewidget.py

@@ -0,0 +1,51 @@
+from datetime import date, datetime, time
+
+from django.forms import SplitDateTimeWidget
+
+from .base import WidgetTest
+
+
+class SplitDateTimeWidgetTest(WidgetTest):
+    widget = SplitDateTimeWidget()
+
+    def test_render_empty(self):
+        self.check_html(self.widget, 'date', '', html=(
+            '<input type="text" name="date_0" /><input type="text" name="date_1" />'
+        ))
+
+    def test_render_none(self):
+        self.check_html(self.widget, 'date', None, html=(
+            '<input type="text" name="date_0" /><input type="text" name="date_1" />'
+        ))
+
+    def test_render_datetime(self):
+        self.check_html(self.widget, 'date', datetime(2006, 1, 10, 7, 30), html=(
+            '<input type="text" name="date_0" value="2006-01-10" />'
+            '<input type="text" name="date_1" value="07:30:00" />'
+        ))
+
+    def test_render_date_and_time(self):
+        self.check_html(self.widget, 'date', [date(2006, 1, 10), time(7, 30)], html=(
+            '<input type="text" name="date_0" value="2006-01-10" />'
+            '<input type="text" name="date_1" value="07:30:00" />'
+        ))
+
+    def test_constructor_attrs(self):
+        widget = SplitDateTimeWidget(attrs={'class': 'pretty'})
+        self.check_html(widget, 'date', datetime(2006, 1, 10, 7, 30), html=(
+            '<input type="text" class="pretty" value="2006-01-10" name="date_0" />'
+            '<input type="text" class="pretty" value="07:30:00" name="date_1" />'
+        ))
+
+    def test_formatting(self):
+        """
+        Use 'date_format' and 'time_format' to change the way a value is
+        displayed.
+        """
+        widget = SplitDateTimeWidget(
+            date_format='%d/%m/%Y', time_format='%H:%M',
+        )
+        self.check_html(widget, 'date', datetime(2006, 1, 10, 7, 30), html=(
+            '<input type="text" name="date_0" value="10/01/2006" />'
+            '<input type="text" name="date_1" value="07:30" />'
+        ))