Adding some testing around updating notes

internal/repository/notestore_test.go

@@ -11,18 +11,36 @@ type mockNoteStore struct {
 }
 
 func (m *mockNoteStore) SaveNote(note models.Note) (models.Note, error) {
-	note.ID = len(m.Notes) + 1
-	m.Notes = append(m.Notes, note)
+	// Save a note
+	if note.ID == 0 {
+		note.ID = len(m.Notes) + 1
+		m.Notes = append(m.Notes, note)
+		return note, nil
+	}
+	// Update a note
+	_, index, err := m.getNoteAndIndexByID(note.ID)
+	if err != nil {
+		return models.Note{}, err
+	}
+	m.Notes[index] = note
 	return note, nil
 }
 
 func (m *mockNoteStore) GetNoteByID(id int) (models.Note, error) {
-	for _, note := range m.Notes {
+	note, _, err := m.getNoteAndIndexByID(id)
+	if err != nil {
+		return models.Note{}, err
+	}
+	return note, nil
+}
+
+func (m *mockNoteStore) getNoteAndIndexByID(id int) (models.Note, int, error) {
+	for i, note := range m.Notes {
 		if note.ID == id {
-			return note, nil
+			return note, i, nil
 		}
 	}
-	return models.Note{}, fmt.Errorf("note with ID %d not found", id)
+	return models.Note{}, -1, fmt.Errorf("note with ID %d not found", id)
 }
 
 func (m *mockNoteStore) GetAllNotes() ([]models.Note, error) {