exceptions for set_start_state

yasmin/src/yasmin/state_machine.cpp

@@ -83,6 +83,15 @@ void StateMachine::add_state(std::string name, std::shared_ptr<State> state) {
 }
 
 void StateMachine::set_start_state(std::string state_name) {
+
+  if (state_name.empty()) {
+    throw std::invalid_argument("Initial state cannot be empty");
+
+  } else if (this->states.find(state_name) == this->states.end()) {
+    throw std::invalid_argument("Initial state '" + state_name +
+                                "' is not in the state machine");
+  }
+
   this->start_state = state_name;
 }
 
@@ -117,10 +126,6 @@ void StateMachine::validate() {
   // check initial state
   if (this->start_state.empty()) {
     throw std::runtime_error("No initial state set");
-
-  } else if (this->states.find(this->start_state) == this->states.end()) {
-    throw std::runtime_error("Initial state label: '" + this->start_state +
-                             "' is not in the state machine");
   }
 
   std::set<std::string> terminal_outcomes;
@@ -189,6 +194,8 @@ void StateMachine::validate() {
 std::string
 StateMachine::execute(std::shared_ptr<blackboard::Blackboard> blackboard) {
 
+  this->validate();
+
   this->current_state_mutex->lock();
   this->current_state = this->start_state;
   this->current_state_mutex->unlock();

yasmin/tests/python/test_state_machine.py

@@ -77,6 +77,18 @@ def test_state_machine_get_current_state(self):
     def test_state_call(self):
         self.assertEqual("outcome4", self.sm())
 
+    def test_set_start_state_empty(self):
+        with self.assertRaises(Exception) as context:
+            self.sm.set_start_state("")
+        self.assertEqual(str(context.exception), "Initial state cannot be empty")
+
+    def test_set_start_state_wrong_state(self):
+        with self.assertRaises(Exception) as context:
+            self.sm.set_start_state("FOO1")
+        self.assertEqual(
+            str(context.exception), "Initial state 'FOO1' is not in the state machine"
+        )
+
     def test_add_repeated_state(self):
         with self.assertRaises(Exception) as context:
             self.sm.add_state(

yasmin/yasmin/state_machine.py

@@ -63,6 +63,13 @@ def add_state(
             self._start_state = name
 
     def set_start_state(self, name: str) -> None:
+
+        if not name:
+            raise Exception("Initial state cannot be empty")
+
+        elif name not in self._states:
+            raise Exception(f"Initial state '{name}' is not in the state machine")
+
         self._start_state = name
 
     def get_start_state(self) -> str:
@@ -77,12 +84,8 @@ def cancel_state(self) -> None:
     def validate(self) -> None:
 
         # check initial state
-        if self._start_state is None:
+        if not self._start_state:
             raise Exception("No initial state set")
-        elif self._start_state not in self._states:
-            raise Exception(
-                f"Initial state label: '{self._start_state}' is not in the state machine"
-            )
 
         terminal_outcomes = []