2 * Copyright 2016 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>
19 #include <folly/futures/detail/FSM.h>
21 using namespace folly::detail;
23 enum class State { A, B };
26 FSM<State> fsm(State::A);
28 int unprotectedCount = 0;
30 // somebody set up us the switch
31 auto tryTransition = [&]{
32 switch (fsm.getState()) {
34 return fsm.updateState(State::A, State::B, [&]{ count++; });
36 return fsm.updateState(State::B, State::A,
37 [&]{ count--; }, [&]{ unprotectedCount--; });
39 return false; // unreachable
42 // keep retrying until success (like a cas)
43 while (!tryTransition()) ;
44 EXPECT_EQ(State::B, fsm.getState());
46 EXPECT_EQ(0, unprotectedCount);
48 while (!tryTransition()) ;
49 EXPECT_EQ(State::A, fsm.getState());
51 EXPECT_EQ(-1, unprotectedCount);
54 TEST(FSM, magicMacrosExample) {
58 int unprotectedCount = 0;
59 MyFSM() : fsm_(State::A) {}
62 FSM_CASE(fsm_, State::A, State::B, [&]{ count++; });
63 FSM_CASE2(fsm_, State::B, State::A,
64 [&]{ count--; }, [&]{ unprotectedCount--; });
72 EXPECT_EQ(State::B, fsm.fsm_.getState());
73 EXPECT_EQ(1, fsm.count);
74 EXPECT_EQ(0, fsm.unprotectedCount);
77 EXPECT_EQ(State::A, fsm.fsm_.getState());
78 EXPECT_EQ(0, fsm.count);
79 EXPECT_EQ(-1, fsm.unprotectedCount);
84 FSM<State> fsm(State::A);
85 EXPECT_EQ(State::A, fsm.getState());
89 FSM<State> fsm(State::A);
90 EXPECT_TRUE(fsm.updateState(State::A, State::B, []{}));
91 EXPECT_EQ(State::B, fsm.getState());
94 TEST(FSM, badUpdate) {
95 FSM<State> fsm(State::A);
96 EXPECT_FALSE(fsm.updateState(State::B, State::A, []{}));
99 TEST(FSM, actionOnUpdate) {
100 FSM<State> fsm(State::A);
102 fsm.updateState(State::A, State::B, [&]{ count++; });
106 TEST(FSM, noActionOnBadUpdate) {
107 FSM<State> fsm(State::A);
109 fsm.updateState(State::B, State::A, [&]{ count++; });
113 TEST(FSM, stateTransitionAfterAction) {
114 FSM<State> fsm(State::A);
115 fsm.updateState(State::A, State::B,
116 [&]{ EXPECT_EQ(State::A, fsm.getState()); });