Added tests for MySQL's SchemaEditor.quote_value().

tests/backends/mysql/test_schema.py

+import unittest
+
+from django.db import connection
+from django.test import TestCase
+
+
+@unittest.skipUnless(connection.vendor == 'mysql', 'MySQL tests')
+class SchemaEditorTests(TestCase):
+    def test_quote_value(self):
+        editor = connection.schema_editor()
+        tested_values = [
+            (42, '42'),
+            (1.754, '1.754'),
+            (False, '0'),
+        ]
+        for value, expected in tested_values:
+            with self.subTest(value=value):
+                self.assertEqual(editor.quote_value(value), expected)