Fix commit confirm

Re-implementation of the commit confirm state mechanic.

Description

Commit-confirm state manager for changes uses channels instead of mutexes now. Also some test coverage improvements.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

api/pnd.go

@@ -177,7 +177,7 @@ func (p *PrincipalNetworkDomainAdapter) CommittedChanges() []uuid.UUID {
 }
 
 // GetChange sends an API call to the controller requesting the specified change
-func (p *PrincipalNetworkDomainAdapter) GetChange(uuid.UUID, ...int) (change.Change, error) {
+func (p *PrincipalNetworkDomainAdapter) GetChange(uuid.UUID) (change.Change, error) {
 	return nil, &errors.ErrNotYetImplemented{}
 }
 
@@ -204,7 +204,7 @@ func (p *PrincipalNetworkDomainAdapter) Confirm(cuid uuid.UUID) error {
 func filterChanges(state ppb.Change_State, resp *ppb.GetResponse) []uuid.UUID {
 	changes := make([]uuid.UUID, 0)
 	for _, ch := range resp.Change {
-		if ch.State == ppb.Change_PENDING {
+		if ch.State == state {
 			id, _ := uuid.Parse(ch.Id)
 			changes = append(changes, id)
 		}