compute api should throw exception if soft reboot invalid state VM

When user perform soft reboot to a VM which in suspended/paused/
stopped/error state, nova compute api should throw exception for
such state.

Change-Id: Ic365c6360f6b7407d9de0dac6ff1093484692cf4
Closes-Bug: #1236930

nova/compute/api.py

@@ -1983,6 +1983,16 @@ def snapshot_volume_backed(self, context, instance, image_meta, name,
                                       task_states.SUSPENDING])
     def reboot(self, context, instance, reboot_type):
         """Reboot the given instance."""
+        if (reboot_type == 'SOFT' and
+                (instance['vm_state'] in [vm_states.STOPPED,
+                                          vm_states.PAUSED,
+                                          vm_states.SUSPENDED,
+                                          vm_states.ERROR])):
+            raise exception.InstanceInvalidState(
+                attr='vm_state',
+                instance_uuid=instance['uuid'],
+                state=instance['vm_state'],
+                method='reboot')
         if ((reboot_type == 'SOFT' and
                 instance['task_state'] == task_states.REBOOTING) or
             (reboot_type == 'HARD' and

nova/tests/compute/test_compute_api.py

@@ -371,7 +371,16 @@ def test_reboot_soft(self):
         self._test_reboot_type(vm_states.ACTIVE, 'SOFT')
 
     def test_reboot_soft_error(self):
-        self._test_reboot_type(vm_states.ERROR, 'SOFT')
+        self._test_reboot_type_fails('SOFT', vm_state=vm_states.ERROR)
+
+    def test_reboot_soft_paused(self):
+        self._test_reboot_type_fails('SOFT', vm_state=vm_states.PAUSED)
+
+    def test_reboot_soft_stopped(self):
+        self._test_reboot_type_fails('SOFT', vm_state=vm_states.STOPPED)
+
+    def test_reboot_soft_suspended(self):
+        self._test_reboot_type_fails('SOFT', vm_state=vm_states.SUSPENDED)
 
     def test_reboot_soft_rebooting(self):
         self._test_reboot_type_fails('SOFT', task_state=task_states.REBOOTING)