Return Set instead of List from acceptedEvents

Author: mantono

lib/src/main/kotlin/io/nexure/fsm/StateMachine.kt

@@ -39,7 +39,7 @@ interface StateMachine<S : Any, E : Any> {
      * Return a list of events that are accepted by the state machine in the given state. The returned list will be an
      * empty list if the state is a terminal state.
      */
-    fun acceptedEvents(state: S): List<E>
+    fun acceptedEvents(state: S): Set<E>
 
     companion object {
         fun <S : Any, E : Any> builder(): StateMachineBuilder.Uninitialized<S, E> = StateMachineBuilder()

lib/src/main/kotlin/io/nexure/fsm/StateMachineImpl.kt

@@ -28,8 +28,8 @@ internal class StateMachineImpl<S : Any, E : Any>(
         return Accepted(next)
     }
 
-    override fun acceptedEvents(state: S): List<E> =
-        allowedTransitions.getOrDefault(state, emptySet()).map { it.second }
+    override fun acceptedEvents(state: S): Set<E> =
+        allowedTransitions.getOrDefault(state, emptySet()).map { it.second }.toSet()
 
     private fun nextState(source: S, event: E): S? {
         val targets: Set<Pair<S, E>> = allowedTransitions.getOrDefault(source, emptySet())

lib/src/test/kotlin/io/nexure/fsm/StateMachineTest.kt

@@ -289,19 +289,19 @@ class StateMachineTest {
             .connect(State.S3, State.S4, Event.E3)
             .build()
 
-        assertEquals(listOf(Event.E1, Event.E2), fsm.acceptedEvents(State.S1))
+        assertEquals(setOf(Event.E1, Event.E2), fsm.acceptedEvents(State.S1))
     }
 
     @Test
-    fun `test acceptedEvents on terminal state`() {
+    fun `test acceptedEvents is empty on terminal state`() {
         val fsm = StateMachine.builder<State, Event>()
             .initial(State.S1)
             .connect(State.S1, State.S2, Event.E1)
             .connect(State.S1, State.S3, Event.E2)
             .connect(State.S3, State.S4, Event.E3)
             .build()
 
-        assertEquals(emptyList<Event>(), fsm.acceptedEvents(State.S4))
+        assertEquals(emptySet<Event>(), fsm.acceptedEvents(State.S4))
     }
 }