mojo: Add promises for python bindings.

mojo/python/tests/promise_unittest.py

+# Copyright 2014 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+import unittest
+
+# pylint: disable=F0401
+from mojo.bindings import promise
+
+
+class PromiseTest(unittest.TestCase):
+
+  def setUp(self):
+    self.accumulated = []
+
+  def _AddToAccumulated(self, res):
+    self.accumulated.append(res)
+    return res
+
+  def testResolve(self):
+    p = promise.Promise.Resolve(0)
+    self.assertEquals(p.state, promise.Promise.STATE_FULLFILLED)
+    p.Then(self._AddToAccumulated)
+    self.assertEquals(self.accumulated, [0])
+
+  def testResolveToPromise(self):
+    p = promise.Promise.Resolve(0)
+    self.assertEquals(p.state, promise.Promise.STATE_FULLFILLED)
+    q = promise.Promise.Resolve(p)
+    self.assertEquals(p.state, promise.Promise.STATE_FULLFILLED)
+    q.Then(self._AddToAccumulated)
+    self.assertEquals(self.accumulated, [0])
+
+  def testReject(self):
+    p = promise.Promise.Reject(0)
+    self.assertEquals(p.state, promise.Promise.STATE_REJECTED)
+    p.Then(onRejected=self._AddToAccumulated)
+    self.assertEquals(self.accumulated, [0])
+
+  def testGeneratorFunctionResolve(self):
+    (p, resolve, _) = _GetPromiseAndFunctions()
+    self.assertEquals(p.state, promise.Promise.STATE_PENDING)
+    p.Then(self._AddToAccumulated)
+    resolve(0)
+    self.assertEquals(p.state, promise.Promise.STATE_FULLFILLED)
+    self.assertEquals(self.accumulated, [0])
+
+  def testGeneratorFunctionReject(self):
+    (p, _, reject) = _GetPromiseAndFunctions()
+    self.assertEquals(p.state, promise.Promise.STATE_PENDING)
+    p.Then(None, self._AddToAccumulated)
+    reject(0)
+    self.assertEquals(p.state, promise.Promise.STATE_REJECTED)
+    self.assertEquals(self.accumulated, [0])
+
+  def testGeneratorFunctionResolveToPromise(self):
+    (p1, resolve, _) = _GetPromiseAndFunctions()
+    p2 = promise.Promise(lambda x, y: x(p1))
+    self.assertEquals(p2.state, promise.Promise.STATE_PENDING)
+    p2.Then(self._AddToAccumulated)
+    resolve(promise.Promise.Resolve(0))
+    self.assertEquals(self.accumulated, [0])
+
+  def testComputation(self):
+    (p, resolve, _) = _GetPromiseAndFunctions()
+    p.Then(lambda x: x+1).Then(lambda x: x+2).Then(self._AddToAccumulated)
+    self.assertEquals(self.accumulated, [])
+    resolve(0)
+    self.assertEquals(self.accumulated, [3])
+
+  def testRecoverAfterException(self):
+    (p, resolve, _) = _GetPromiseAndFunctions()
+    p.Then(_ThrowException).Catch(self._AddToAccumulated)
+    self.assertEquals(self.accumulated, [])
+    resolve(0)
+    self.assertEquals(len(self.accumulated), 1)
+    self.assertIsInstance(self.accumulated[0], RuntimeError)
+    self.assertEquals(self.accumulated[0].message, 0)
+
+  def testMultipleRejectResolve(self):
+    (p, resolve, reject) = _GetPromiseAndFunctions()
+    p.Then(self._AddToAccumulated, self._AddToAccumulated)
+    resolve(0)
+    self.assertEquals(self.accumulated, [0])
+    resolve(0)
+    self.assertEquals(self.accumulated, [0])
+    reject(0)
+    self.assertEquals(self.accumulated, [0])
+
+    self.accumulated = []
+    (p, resolve, reject) = _GetPromiseAndFunctions()
+    p.Then(self._AddToAccumulated, self._AddToAccumulated)
+    reject(0)
+    self.assertEquals(self.accumulated, [0])
+    resolve(0)
+    self.assertEquals(self.accumulated, [0])
+    reject(0)
+    self.assertEquals(self.accumulated, [0])
+
+  def testAll(self):
+    promises_and_functions = [_GetPromiseAndFunctions() for x in xrange(10)]
+    promises = [x[0] for x in promises_and_functions]
+    all_promise = promise.Promise.All(*promises)
+    res = []
+    def AddToRes(values):
+      res.append(values)
+    all_promise.Then(AddToRes, AddToRes)
+    for i, (_, resolve, _) in enumerate(promises_and_functions):
+      self.assertEquals(len(res), 0)
+      resolve(i)
+    self.assertEquals(len(res), 1)
+    self.assertEquals(res[0], [i for i in xrange(10)])
+    self.assertEquals(all_promise.state, promise.Promise.STATE_FULLFILLED)
+
+  def testAllFailure(self):
+    promises_and_functions = [_GetPromiseAndFunctions() for x in xrange(10)]
+    promises = [x[0] for x in promises_and_functions]
+    all_promise = promise.Promise.All(*promises)
+    res = []
+    def AddToRes(values):
+      res.append(values)
+    all_promise.Then(AddToRes, AddToRes)
+    for i in xrange(10):
+      if i <= 5:
+        self.assertEquals(len(res), 0)
+      else:
+        self.assertEquals(len(res), 1)
+      if i != 5:
+        promises_and_functions[i][1](i)
+      else:
+        promises_and_functions[i][2]('error')
+    self.assertEquals(len(res), 1)
+    self.assertEquals(res[0], 'error')
+    self.assertEquals(all_promise.state, promise.Promise.STATE_REJECTED)
+
+  def testRace(self):
+    promises_and_functions = [_GetPromiseAndFunctions() for x in xrange(10)]
+    promises = [x[0] for x in promises_and_functions]
+    race_promise = promise.Promise.Race(*promises)
+    res = []
+    def AddToRes(values):
+      res.append(values)
+    race_promise.Then(AddToRes, AddToRes)
+    self.assertEquals(len(res), 0)
+    promises_and_functions[7][1]('success')
+    self.assertEquals(len(res), 1)
+    for i, (f) in enumerate(promises_and_functions):
+      f[1 + (i % 2)](i)
+    self.assertEquals(len(res), 1)
+    self.assertEquals(res[0], 'success')
+    self.assertEquals(race_promise.state, promise.Promise.STATE_FULLFILLED)
+
+  def testRaceFailure(self):
+    promises_and_functions = [_GetPromiseAndFunctions() for x in xrange(10)]
+    promises = [x[0] for x in promises_and_functions]
+    race_promise = promise.Promise.Race(*promises)
+    res = []
+    def AddToRes(values):
+      res.append(values)
+    race_promise.Then(AddToRes, AddToRes)
+    self.assertEquals(len(res), 0)
+    promises_and_functions[7][2]('error')
+    self.assertEquals(len(res), 1)
+    for i, (f) in enumerate(promises_and_functions):
+      f[1 + (i % 2)](i)
+    self.assertEquals(len(res), 1)
+    self.assertEquals(res[0], 'error')
+    self.assertEquals(race_promise.state, promise.Promise.STATE_REJECTED)
+
+
+def _GetPromiseAndFunctions():
+  functions = {}
+  def GeneratorFunction(resolve, reject):
+    functions['resolve'] = resolve
+    functions['reject'] = reject
+  p = promise.Promise(GeneratorFunction)
+  return (p, functions['resolve'], functions['reject'])
+
+
+def _ThrowException(x):
+  raise RuntimeError(x)