Add tests for validate

wp1/selection/models/petscan_test.py

@@ -105,3 +105,24 @@ def test_build_non_200(self, mock_requests_get):
       actual = self.builder.build(
           'text/tab-separated-values',
           url='https://petscan.wmflabs.org.fake/?psid=42')
+
+  def test_validate(self):
+    actual = self.builder.validate(
+        url='https://petscan.wmflabs.org.fake/?psid=42&format=wiki')
+    self.assertEqual(('', '', []), actual)
+
+  def test_validate_missing_url(self):
+    actual = self.builder.validate()
+    self.assertEqual(('', '', ['Missing URL parameter']), actual)
+
+  def test_validate_not_a_url(self):
+    afctual = self.builder.validate(url='http:// foo bar [baz]')
+    self.assertEqual(
+        ('', 'http:// foo bar [baz]', ['That doesn\'t look like a valid URL.']),
+        actual)
+
+  def test_validate_not_a_petscan_url(self):
+    afctual = self.builder.validate(url='http://en.wikipedia.org/')
+    self.assertEqual(
+        ('', 'http://en.wikipedia.org/',
+         ['Only URLs that lead to petscan.wmflabs.org are allowed.']), actual)