diff --git a/integraality/templates/update_unknown_error.html b/integraality/templates/update_unknown_error.html
index 761a30c..15884f6 100644
--- a/integraality/templates/update_unknown_error.html
+++ b/integraality/templates/update_unknown_error.html
@@ -1,10 +1,10 @@
 {% extends "base.html" %}
 
 {% block content %}
 <div class="alert alert-danger">
-<p>Something catastrophic happened when procesing page <a href="https://wikidata.org/wiki/{{ page }}">{{ page }}</a>.</p>
+<p>Something catastrophic happened when processing page <a href="https://wikidata.org/wiki/{{ page }}">{{ page }}</a>.</p>
 <p>Please report this on Phabricator.</p>
 <p>{{ error_type }}</p>
 <p>{{ error_message }}</p>
 </div>
 {% endblock %}
diff --git a/integraality/tests/test_app.py b/integraality/tests/test_app.py
index 9e33a49..0d04d40 100644
--- a/integraality/tests/test_app.py
+++ b/integraality/tests/test_app.py
@@ -1,21 +1,74 @@
 # -*- coding: utf-8  -*-
 import unittest
+from unittest.mock import patch
 
 from app import app
 
+from pages_processor import ProcessingException
+
 
 class AppTests(unittest.TestCase):
 
     def setUp(self):
         app.config['TESTING'] = True
         self.app = app.test_client()
 
+
+class BasicTests(AppTests):
+
     def test_index_page(self):
         response = self.app.get('/')
         self.assertEqual(response.status_code, 200)
         self.assertIn("<h1>InteGraality</h1>", response.get_data(as_text=True))
 
     def test_404_page(self):
         response = self.app.get('/unexisting_page')
         self.assertEqual(response.status_code, 404)
         self.assertIn("This page does not exist.", response.get_data(as_text=True))
+
+
+class UpdateTests(AppTests):
+
+    def setUp(self):
+        super().setUp()
+        patcher = patch('app.PagesProcessor', autospec=True)
+        self.mock_pages_processor = patcher.start()
+        self.addCleanup(patcher.stop)
+        self.page_title = 'Foo'
+        self.linked_page = '<a href="https://wikidata.org/wiki/{page}">{page}</a>'.format(page=self.page_title)
+
+    def assertSuccessPage(self, response, message):
+        """A custom assertion for a success page."""
+        self.assertEqual(response.status_code, 200)
+        contents = response.get_data(as_text=True)
+        self.assertIn("alert-success", contents)
+        self.assertIn(message, contents)
+
+    def assertErrorPage(self, response, message):
+        """A custom assertion for an error page."""
+        self.assertEqual(response.status_code, 200)
+        contents = response.get_data(as_text=True)
+        self.assertIn("alert-danger", contents)
+        self.assertIn(message, contents)
+
+    def test_update_success(self):
+        response = self.app.get('/update?page=%s' % self.page_title)
+        self.mock_pages_processor.assert_called_once_with()
+        self.mock_pages_processor.return_value.process_one_page.assert_called_once_with(page_title=self.page_title)
+        self.assertSuccessPage(response, 'Updated page ')
+
+    def test_update_error_processing_exception(self):
+        self.mock_pages_processor.return_value.process_one_page.side_effect = ProcessingException
+        response = self.app.get('/update?page=%s' % self.page_title)
+        self.mock_pages_processor.assert_called_once_with()
+        self.mock_pages_processor.return_value.process_one_page.assert_called_once_with(page_title=self.page_title)
+        message = '<p>Something went wrong when updating page {page}.</p>'.format(page=self.linked_page)
+        self.assertErrorPage(response, message)
+
+    def test_update_error_unknown_exception(self):
+        self.mock_pages_processor.return_value.process_one_page.side_effect = ValueError
+        response = self.app.get('/update?page=%s' % self.page_title)
+        self.mock_pages_processor.assert_called_once_with()
+        self.mock_pages_processor.return_value.process_one_page.assert_called_once_with(page_title=self.page_title)
+        message = '<p>Something catastrophic happened when processing page {page}.</p>'.format(page=self.linked_page)
+        self.assertErrorPage(response, message)