2 * Copyright 2014 Facebook, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
17 #include <gtest/gtest.h>
18 #include <folly/wangle/futures/detail/FSM.h>
20 using namespace folly::wangle::detail;
22 enum class State { A, B };
25 FSM<State> fsm(State::A);
27 int unprotectedCount = 0;
29 // somebody set up us the switch
30 auto tryTransition = [&]{
31 switch (fsm.getState()) {
33 return fsm.updateState(State::A, State::B, [&]{ count++; });
35 return fsm.updateState(State::B, State::A,
36 [&]{ count--; }, [&]{ unprotectedCount--; });
38 return false; // unreachable
41 // keep retrying until success (like a cas)
42 while (!tryTransition()) ;
43 EXPECT_EQ(State::B, fsm.getState());
45 EXPECT_EQ(0, unprotectedCount);
47 while (!tryTransition()) ;
48 EXPECT_EQ(State::A, fsm.getState());
50 EXPECT_EQ(-1, unprotectedCount);
53 TEST(FSM, magicMacrosExample) {
54 struct MyFSM : public FSM<State> {
56 int unprotectedCount = 0;
57 MyFSM() : FSM<State>(State::A) {}
60 FSM_CASE(State::A, State::B, [&]{ count++; });
61 FSM_CASE2(State::B, State::A,
62 [&]{ count--; }, [&]{ unprotectedCount--; });
70 EXPECT_EQ(State::B, fsm.getState());
71 EXPECT_EQ(1, fsm.count);
72 EXPECT_EQ(0, fsm.unprotectedCount);
75 EXPECT_EQ(State::A, fsm.getState());
76 EXPECT_EQ(0, fsm.count);
77 EXPECT_EQ(-1, fsm.unprotectedCount);
82 FSM<State> fsm(State::A);
83 EXPECT_EQ(State::A, fsm.getState());
87 FSM<State> fsm(State::A);
88 EXPECT_TRUE(fsm.updateState(State::A, State::B, []{}));
89 EXPECT_EQ(State::B, fsm.getState());
92 TEST(FSM, badUpdate) {
93 FSM<State> fsm(State::A);
94 EXPECT_FALSE(fsm.updateState(State::B, State::A, []{}));
97 TEST(FSM, actionOnUpdate) {
98 FSM<State> fsm(State::A);
100 fsm.updateState(State::A, State::B, [&]{ count++; });
104 TEST(FSM, noActionOnBadUpdate) {
105 FSM<State> fsm(State::A);
107 fsm.updateState(State::B, State::A, [&]{ count++; });
111 TEST(FSM, stateTransitionAfterAction) {
112 FSM<State> fsm(State::A);
113 fsm.updateState(State::A, State::B,
114 [&]{ EXPECT_EQ(State::A, fsm.getState()); });