All files / xstate/test interpreter.test.ts

100% Statements 103/103
100% Branches 2/2
100% Functions 30/30
100% Lines 92/92

Press n or j to go to the next uncovered block, b, p or k for the previous block.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 2471x 1x 1x 1x 1x 1x   1x                                                         1x 1x 1x   1x     1x     1x 1x     1x   1x 1x     1x 1x   1x     1x 1x 1x 1x 4x   4x 4x                 1x     1x 1x   1x 1x           1x 2x   1x 2x   1x 3x           1x 3x           1x 4x                 1x 1x   1x                                 2x 2x           1x 1x   1x   1x     1x 1x   1x   1x   1x   1x       1x   2x   1x     1x 1x   1x 1x   1x 1x 1x             1x 1x   1x   1x   1x     1x 1x 2x   1x 1x 1x   1x 1x 1x     1x 1x   1x                 2x 2x               1x 2x     1x 1x   1x 1x      
import { interpret, Interpreter, SimulatedClock } from '../src/interpreter';
import { assert } from 'chai';
import { machine as idMachine } from './fixtures/id';
import { Machine, actions } from '../src';
import { State } from '../src/State';
import { log, assign } from '../src/actions';
 
const lightMachine = Machine({
  id: 'light',
  initial: 'green',
  states: {
    green: {
      onEntry: [actions.send('TIMER', { delay: 10 })],
      on: {
        TIMER: 'yellow',
        KEEP_GOING: {
          target: 'green',
          actions: [actions.cancel('TIMER')],
          internal: true
        }
      }
    },
    yellow: {
      onEntry: [actions.send('TIMER', { delay: 10 })],
      on: {
        TIMER: 'red'
      }
    },
    red: {
      after: {
        10: 'green'
      }
    }
  }
});
 
describe('interpreter', () => {
  it('creates an interpreter', () => {
    const interpreter = interpret(idMachine);
 
    assert.instanceOf(interpreter, Interpreter);
  });
 
  it('immediately notifies the listener with the initial state', () => {
    let result: State<any> | undefined;
 
    const interpreter = interpret(idMachine).onTransition(
      initialState => (result = initialState)
    );
 
    interpreter.start();
 
    assert.instanceOf(result, State);
    assert.deepEqual(result!.value, idMachine.initialState.value);
  });
 
  it('.initialState returns the initial state', () => {
    const interpreter = interpret(idMachine);
 
    assert.deepEqual(interpreter.initialState, idMachine.initialState);
  });
 
  describe('send with delay', () => {
    it('can send an event after a delay', () => {
      const currentStates: Array<State<any>> = [];
      const listener = state => {
        currentStates.push(state);
 
        if (currentStates.length === 4) {
          assert.deepEqual(currentStates.map(s => s.value), [
            'green',
            'yellow',
            'red',
            'green'
          ]);
        }
      };
 
      const interpreter = interpret(lightMachine, {
        clock: new SimulatedClock()
      }).onTransition(listener);
      const clock = interpreter.clock as SimulatedClock;
      interpreter.start();
 
      clock.increment(5);
      assert.equal(
        currentStates[0]!.value,
        'green',
        'State should still be green before delayed send'
      );
 
      clock.increment(5);
      assert.deepEqual(currentStates.map(s => s.value), ['green', 'yellow']);
 
      clock.increment(5);
      assert.deepEqual(currentStates.map(s => s.value), ['green', 'yellow']);
 
      clock.increment(5);
      assert.deepEqual(currentStates.map(s => s.value), [
        'green',
        'yellow',
        'red'
      ]);
 
      clock.increment(5);
      assert.deepEqual(currentStates.map(s => s.value), [
        'green',
        'yellow',
        'red'
      ]);
 
      clock.increment(5);
      assert.deepEqual(currentStates.map(s => s.value), [
        'green',
        'yellow',
        'red',
        'green'
      ]);
    });
  });
 
  describe('activities', () => {
    let activityState = 'off';
 
    const activityMachine = Machine(
      {
        id: 'activity',
        initial: 'on',
        states: {
          on: {
            activities: 'myActivity',
            on: {
              TURN_OFF: 'off'
            }
          },
          off: {}
        }
      },
      {
        activities: {
          myActivity: () => {
            activityState = 'on';
            return () => (activityState = 'off');
          }
        }
      }
    );
 
    it('should start activities', () => {
      const interpreter = interpret(activityMachine);
 
      interpreter.start();
 
      assert.equal(activityState, 'on');
    });
 
    it('should stop activities', () => {
      const interpreter = interpret(activityMachine);
 
      interpreter.start();
 
      assert.equal(activityState, 'on');
 
      interpreter.send('TURN_OFF');
 
      assert.equal(activityState, 'off');
    });
  });
 
  it('can cancel a delayed event', () => {
    let currentState: State<any>;
    const listener = state => (currentState = state);
 
    const interpreter = interpret(lightMachine, {
      clock: new SimulatedClock()
    }).onTransition(listener);
    const clock = interpreter.clock as SimulatedClock;
    interpreter.start();
 
    clock.increment(5);
    interpreter.send('KEEP_GOING');
 
    assert.deepEqual(currentState!.value, 'green');
    clock.increment(10);
    assert.deepEqual(
      currentState!.value,
      'green',
      'should still be green due to canceled event'
    );
  });
 
  it('should throw an error if an event is sent to an uninitialized interpreter', () => {
    const interpreter = interpret(lightMachine);
 
    assert.throws(() => interpreter.send('SOME_EVENT'));
 
    interpreter.start();
 
    assert.doesNotThrow(() => interpreter.send('SOME_EVENT'));
  });
 
  it('should not update when stopped', () => {
    let state = lightMachine.initialState;
    const interpreter = interpret(lightMachine).onTransition(s => (state = s));
 
    interpreter.start();
    interpreter.send('TIMER'); // yellow
    assert.deepEqual(state.value, 'yellow');
 
    interpreter.stop();
    interpreter.send('TIMER'); // red if interpreter is not stopped
    assert.deepEqual(state.value, 'yellow');
  });
 
  it('should be able to log', () => {
    const logs: any[] = [];
 
    const logMachine = Machine({
      id: 'log',
      initial: 'x',
      context: { count: 0 },
      states: {
        x: {
          on: {
            LOG: {
              actions: [
                assign({ count: ctx => ctx.count + 1 }),
                log(ctx => ctx)
              ]
            }
          }
        }
      }
    });
 
    const interpreter = interpret(logMachine, {
      logger: msg => logs.push(msg)
    }).start();
 
    interpreter.send('LOG');
    interpreter.send('LOG');
 
    assert.lengthOf(logs, 2);
    assert.deepEqual(logs, [{ count: 1 }, { count: 2 }]);
  });
});