how to generate fake data using moq for unit test? - unit-testing

Question

I need to generate some data to unit test my repositories. i was using a loop to generate a list of objects, see codes below. I learned moq is a great mocking library, Can I use moq to generate that and how do I do it?
public IQueryable<Category> GetCategories()
{
IList<Category> result = new List<Category>();
for (int i = 1; i <= 2; i++)
{
Category c = new Category();
c.ID = i;
c.Name = "Parent" + i.ToString();
c.ParentID = 0;
for (int x = i*10; x < i*10+5; x++)
{
Category sub = new Category();
sub.ID = x;
sub.Name = "Sub" + x.ToString();
sub.ParentID = i;
result.Add(sub);
}
result.Add(c);
}
return result.AsQueryable<Category>();
}

Answer 1

You can't use Moq to create the data, but you can use AutoFixture:
public IQueryable<Category> GetCategories()
{
return fixture.CreateMany<Category>().AsQueryable();
}
However, this will not give you a hierarchical tree. It will return objects like this:
Object 1:
- ID = 0
- ParentID = 1
Object 2:
- ID = 2
- ParentID = 3
etc.
If you really need to have this hierarchical data, you would need to use the following code:
public IQueryable<Category> GetCategories()
{
var result = new List<Category>();
// Create the parents
var parents = fixture.Build<Category>()
.Without(x => x.ParentID)
.CreateMany());
result.AddRange(parents);
result.AddRange(parents.SelectMany(p => fixture.Build<Category>()
.With(x => x.ParentID, p.ID)
.CreateMany()));
return result.AsQueryable();
}
This will add multiple parents with multiple subs for each parent.

Answer 2

You can use faker.net to generate fake data. for Example: for dotnet core project its Faker.NETCore.
dotnet add package Faker.NETCore -v 1.0.1
and then use the same in your code in the following manner:-
public void GetStudent()
{
var st = new Student()
st.FirstName = Faker.Name.First();
st.LastName = Faker.Name.Last();
st.Mobile = Faker.Phone.Number();
}