RunUnitTests.py

import os
import fnmatch
import unittest
import webapp2
import importlib
from time import clock

class RunUnitTests(webapp2.RequestHandler):

    def get(self):        
        self.response.headers['Content-Type'] = 'text/plain'

        suite = unittest.TestSuite()
        loader = unittest.TestLoader()
        testCases = self._findTestCases()
        #print testCases

        for testCase in testCases:
            suite.addTests(loader.loadTestsFromTestCase(testCase))

        startTime = clock()
        result = unittest.TextTestRunner(verbosity=2).run(suite)
        stopTime = clock()

        self.response.out.write(('Test cases (%d):\n' % len(testCases)) + '\n'.join(map(repr, testCases)) + '\n\n')
        self._printTestResultsGroup(result, 'errors')
        self._printTestResultsGroup(result, 'failures')

        self.response.out.write('Total tests: %d\n' % result.testsRun)
        self.response.out.write('Status: %s (%s ms)\n' % ('OK' if result.wasSuccessful() else 'FAILED', (stopTime - startTime) * 1000))

    def _findTestCases(self):
        testCases = []
        for root, dirnames, filenames in os.walk('.'):
            for filename in fnmatch.filter(filenames, 'Test*.py'):
                classPath = os.path.splitext(os.path.join(root, filename)[2:])[0].replace('/', '.')
                className = os.path.splitext(filename)[0]
                testCases.append(getattr(importlib.import_module(classPath), className))

        return testCases        

    def _printTestResultsGroup(self, result, name):
        list = getattr(result, name)
        if len(list):
            self.response.out.write("%s (%d):\n" % (name.capitalize(), len(list)))
            for item in list:
                self.response.out.write('%s\n' % item[0])
            self.response.out.write('\n')

Thanks for the gist! :) Suggestion: on line 36, replace '/' with os.sep for platform compat. There's no pull request for gists (afaik), but I made the change here if you like:
https://gist.github.com/newbyca/ef3aabe5f7712e2bb1ef