one-to-many mapping in grails throwing exception - grails

Question

I am new to Groovy & Grails. I am working on one of the sample one-to-many relationship in Grails.
The below is the code.
class User {
//properties
String login
String password
String role
//constraints and order of display of fields in UI
static constraints = {
login(blank: false, nullable: false, unique: true)
password(blank: false, nullable: false, password: true)
role(inList:["Admin", "Member"])
}
static hasMany = [posts : Post]
}
class Post {
String content
Date dateCreated
static constraints = {
content(blank: true)
}
static belongsTo = [user : User]
}
My Test class in Groovy
#TestFor(User)
class UserTests {
void testUserToPost() {
def user = new User(login: "joe", password: "joe", role:"Admin")
user.addToPosts(new Post(content: "First"));
user.addToPosts(new Post(content: "Second"));
user.addToPosts(new Post(content: "Third"));
user.save(flush: true)
assertEquals 3, User.get(user.id).posts.size()
}
}
While running the test class, getting following exception:
groovy.lang.MissingMethodException: No signature of method: com.library.forum.User.addToPosts() is applicable for argument types: (com.library.forum.Post) values: [com.library.forum.Post : (unsaved)]
Possible solutions: getPosts() at com.library.forum.UserTests.testUserToPost(UserTests.groovy:17)
Can anyone tell me where is the problem in code.

Answer 1

Since Grails 2.1.4, there's a change in mock behavior because of performance issue. So you need to mock all associated entities of the mocked entity.
See GRAILS-9637 - Due to a performance issue, #Mock no longer mocks
associated entities of the mocked entity. These have to be manually
specified. For example the following test will fail in 2.1.4 and
above:
#Mock(Author)
void testAddToBooks() {
def a = new Author()
a.addToBooks(new Book())
}
To correct the above test you need to mock both Author and Book:
#Mock([Author, Book])
void testAddToBooks() {
def a = new Author()
a.addToBooks(new Book())
}
You can check this reference.

Answer 2

You need to mock all related domain classes. Change :
#TestFor(User)
class UserTests {
to
#TestFor(User)
#Mock(Post)
class UserTests {
If you need, the mock annotation support a list of classes, for example: #Mock([Domain1, Domain2, Domain3])