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_textinput.py

@@ -0,0 +1,78 @@
+# -*- coding: utf-8 -*-
+from __future__ import unicode_literals
+
+from django.forms import TextInput
+from django.utils.safestring import mark_safe
+
+from .base import WidgetTest
+
+
+class TextInputTest(WidgetTest):
+    widget = TextInput()
+
+    def test_render(self):
+        self.check_html(self.widget, 'email', '', html='<input type="text" name="email" />')
+
+    def test_render_none(self):
+        self.check_html(self.widget, 'email', None, html='<input type="text" name="email" />')
+
+    def test_render_value(self):
+        self.check_html(self.widget, 'email', 'test@example.com', html=(
+            '<input type="text" name="email" value="test@example.com" />'
+        ))
+
+    def test_render_boolean(self):
+        """
+        Boolean values are rendered to their string forms ("True" and
+        "False").
+        """
+        self.check_html(self.widget, 'get_spam', False, html=(
+            '<input type="text" name="get_spam" value="False" />'
+        ))
+        self.check_html(self.widget, 'get_spam', True, html=(
+            '<input type="text" name="get_spam" value="True" />'
+        ))
+
+    def test_render_quoted(self):
+        self.check_html(
+            self.widget, 'email', 'some "quoted" & ampersanded value',
+            html='<input type="text" name="email" value="some &quot;quoted&quot; &amp; ampersanded value" />',
+        )
+
+    def test_render_custom_attrs(self):
+        self.check_html(
+            self.widget, 'email', 'test@example.com', attrs={'class': 'fun'},
+            html='<input type="text" name="email" value="test@example.com" class="fun" />',
+        )
+
+    def test_render_unicode(self):
+        self.check_html(
+            self.widget, 'email', 'ŠĐĆŽćžšđ', attrs={'class': 'fun'},
+            html=(
+                '<input type="text" name="email" '
+                'value="\u0160\u0110\u0106\u017d\u0107\u017e\u0161\u0111" class="fun" />'
+            ),
+        )
+
+    def test_constructor_attrs(self):
+        widget = TextInput(attrs={'class': 'fun', 'type': 'email'})
+        self.check_html(widget, 'email', '', html='<input type="email" class="fun" name="email" />')
+        self.check_html(
+            widget, 'email', 'foo@example.com',
+            html='<input type="email" class="fun" value="foo@example.com" name="email" />',
+        )
+
+    def test_attrs_precedence(self):
+        """
+        `attrs` passed to render() get precedence over those passed to the
+        constructor
+        """
+        widget = TextInput(attrs={'class': 'pretty'})
+        self.check_html(
+            widget, 'email', '', attrs={'class': 'special'},
+            html='<input type="text" class="special" name="email" />',
+        )
+
+    def test_attrs_safestring(self):
+        widget = TextInput(attrs={'onBlur': mark_safe("function('foo')")})
+        self.check_html(widget, 'email', '', html='<input onBlur="function(\'foo\')" type="text" name="email" />')