unit test fails in edit _get action - asp.net-mvc

Question

i wrote a unit test for edit_get action
My controller action is
public class GroupController : Controller
{
private readonly IGroupService groupService;
public GroupController(IGroupService groupService)
{
this.groupService = groupService;
}
public ActionResult EditGroup(int id)
{
var group = groupService.GetGroup(id);
CreateGroupFormModel editGroup = Mapper.Map<Group, CreateGroupFormModel>(group);
if (group == null)
{
return HttpNotFound();
}
return View("_EditGroup", editGroup);
}
the controller actionis working fine.
but when i am writing my unit test it get failed
my test is
[Test]
public void Edit_Get_ReturnsView()
{
//Arrange
CreateGroupFormModel group = new CreateGroupFormModel()
{
GroupId = 2,
GroupName = "Test",
Description = "test" };
GroupController controller = new GroupController();
var fake = groupService.GetGroup(2);
groupRepository.Setup(x => x.GetById(2)).Returns(fake);
Mapper.CreateMap<CreateGroupFormModel, Group>().ForAllMembers(opt => opt.Ignore());
Mapper.AssertConfigurationIsValid();
ViewResult actual = controller.EditGroup(2) as ViewResult;
Assert.IsNotNull(actual, "View Result is null");
}
can any one help me. the test fails as
Expected Not Null
actual Null

Answer 1

In your controller action you are calling var group = groupService.GetGroup(id); and it is not very clear where this groupService is coming from. In your unit test you must mock it. For this to be possible your GroupController must take this dependency as constructor injection.
Also in your unit test you seem to have declared some group variable which is never used.
For example:
public class GroupController: Controller
{
private readonly IGroupService groupService;
public GroupController(IGroupService groupService)
{
this.groupService = groupService;
}
public ActionResult EditGroup(int id)
{
var group = this.groupService.GetGroup(id);
CreateGroupFormModel editGroup = Mapper.Map<Group, CreateGroupFormModel>(group);
if (group == null)
{
return HttpNotFound();
}
return View("_EditGroup", editGroup);
}
}
and now in your unit test you could mock this group service and provide expectations on the result of the GetGroup method:
[Test]
public void Edit_Get_ReturnsView()
{
// arrange
var group = new CreateGroupFormModel
{
GroupId = 2,
GroupName ="Test",
Description ="test"
};
var groupServiceMock = new Mock<IGroupService>();
groupServiceMock.Setup(x => x.GetGroup(group.GroupId)).Returns(group);
var sut = new GroupController(groupServiceMock.Object);
Mapper.CreateMap<CreateGroupFormModel, Group>().ForAllMembers(opt => opt.Ignore());
Mapper.AssertConfigurationIsValid();
// act
var actual = sut.EditGroup(group.GroupId) as ViewResult;
// assert
Assert.IsNotNull(actual);
Assert.IsInstanceOfType(typeof(ViewResult), actual);
}