func addRU(c *gc.C, svc *state.Service, rel *state.Relation, principal *state.Unit) (*state.Unit, *state.RelationUnit) {
// Given the service svc in the relation rel, add a unit of svc and create
// a RelationUnit with rel. If principal is supplied, svc is assumed to be
// subordinate and the unit will be created by temporarily entering the
// relation's scope as the principal.
var u *state.Unit
if principal == nil {
unit, err := svc.AddUnit()
c.Assert(err, gc.IsNil)
u = unit
} else {
origUnits, err := svc.AllUnits()
c.Assert(err, gc.IsNil)
pru, err := rel.Unit(principal)
c.Assert(err, gc.IsNil)
err = pru.EnterScope(nil) // to create the subordinate
c.Assert(err, gc.IsNil)
err = pru.LeaveScope() // to reset to initial expected state
c.Assert(err, gc.IsNil)
newUnits, err := svc.AllUnits()
c.Assert(err, gc.IsNil)
for _, unit := range newUnits {
found := false
for _, old := range origUnits {
if unit.Name() == old.Name() {
found = true
break
}
}
if !found {
u = unit
break
}
}
c.Assert(u, gc.NotNil)
}
preventUnitDestroyRemove(c, u)
ru, err := rel.Unit(u)
c.Assert(err, gc.IsNil)
return u, ru
}
func assertAllUnits(c *gc.C, service *state.Service, expected int) {
units, err := service.AllUnits()
c.Assert(err, gc.IsNil)
c.Assert(units, gc.HasLen, expected)
}