Skip to content

Commit

Permalink
Lightly touch EntityFramework article (#129)
Browse files Browse the repository at this point in the history
  • Loading branch information
@ivo-stoilov
ivo-stoilov authored Nov 7, 2024
1 parent 1599f26 commit 3a2fda3
Showing 1 changed file with 115 additions and 117 deletions.
232 changes: 115 additions & 117 deletions advanced-usage/entity-framework-mocking.md
View file
Original file line number Diff line number Diff line change
Expand Up @@ -17,36 +17,35 @@ __Telerik® JustMock__ allows you to perform unit testing in conjunctions with t

With __Microsoft Entity Framework__, you develop data access applications by using a conceptual application model instead of a relational storage schema.

__JustMock__ supports the Microsoft Entity Framework thanks to the [Telerik.JustMock.EntityFramework](https://github.com/tailsu/Telerik.JustMock.EntityFramework) package. This package allows you to easily create in-memory mocks of the DbSet and DbContext types. It also provides additional mocking amenities for JustMock.

In this topic, we will cover some scenarios in unit testing Microsoft Entity Framework. In the examples below, we use the `DbContext` class along with the following methods:

#### __[C#]__

{{region EntityFramework#Samples}}
public class NerdDinners : DbContext
{
public DbSet<Dinner> Dinners { get; set; }
public DbSet<RSVP> RSVPs { get; set; }
}

public class Dinner
{
public int DinnerID { get; set; }
public string Title { get; set; }
public DateTime EventDate { get; set; }
public string Address { get; set; }
public string HostedBy { get; set; }
}

public class RSVP
{
public int RSVPID { get; set; }
public int DinnerID { get; set; }
public string AtendeeEmail { get; set; }
}

{{endregion}}
__JustMock__ supports both EntityFramework and EntityFrameworkCore thanks to the extension packages respectively [Telerik.JustMock.EntityFramework](https://github.com/telerik/Telerik.JustMock.EntityFramework) and [Telerik.JustMock.EntityFrameworkCore](https://github.com/telerik/Telerik.JustMock.EntityFrameworkCore). The packages allows you to easily create in-memory mocks of the DbSet and DbContext types. It also provides additional mocking amenities for JustMock.

In this topic, we will cover some common scenarios in the EntityFramework unit testing. In the examples below, we use the `DbContext` class along with the following methods:

#### __[C#]__

{{region EntityFramework#Samples}}
public class NerdDinners : DbContext
{
public DbSet<Dinner> Dinners { get; set; }
public DbSet<RSVP> RSVPs { get; set; }
}

public class Dinner
{
public int DinnerID { get; set; }
public string Title { get; set; }
public DateTime EventDate { get; set; }
public string Address { get; set; }
public string HostedBy { get; set; }
}

public class RSVP
{
public int RSVPID { get; set; }
public int DinnerID { get; set; }
public string AtendeeEmail { get; set; }
}
{{endregion}}


## Returning A Fake Collection
Expand All @@ -55,19 +54,19 @@ The following steps demonstrate how to return a fake collection:

1. Create a method that returns a fake collection of `Dinner`s. For this example, we use the code below:

#### __[C#]__
#### __[C#]__

{{region EntityFramework#FakeDinnersReturn}}
{{region EntityFramework#FakeDinnersReturn}}
public IList<Dinner> FakeDinners()
{
List<Dinner> fakeDin = new List<Dinner>
{
new Dinner { Address = "1 Microsoft way", DinnerID = 1, EventDate =DateTime.Now, HostedBy = "Telerik" , Title = "Telerik Dinner"}
};
return fakeDin;
}
{{endregion}}
{
List<Dinner> fakeDin = new List<Dinner>
{
new Dinner { Address = "1 Microsoft way", DinnerID = 1, EventDate =DateTime.Now, HostedBy = "Telerik" , Title = "Telerik Dinner"}
};

return fakeDin;
}
{{endregion}}

1. Create a new instance of the `NerdDinners` class.

Expand All @@ -81,101 +80,100 @@ The following steps demonstrate how to return a fake collection:
>
> Note that when you use `ReturnsCollection()` you must be using the `Telerik.JustMock.Helpers;`.
#### __[C#]__

{{region EntityFramework#MockingCollectionReturn}}
[TestMethod]
public void ShouldReturnFakeCollectionWhenExpected()
{
NerdDinners nerdDinners = new NerdDinners();

// Arrange
Mock.Arrange(() => nerdDinners.Dinners).ReturnsCollection(FakeDinners());

// Act
var query = from d in nerdDinners.Dinners
where d.DinnerID == 1
select d;

// Assert
Assert.AreEqual(1, query.Count());
Assert.AreEqual(1, query.First().DinnerID);

}
{{endregion}}
#### __[C#]__

{{region EntityFramework#MockingCollectionReturn}}
[TestMethod]
public void ShouldReturnFakeCollectionWhenExpected()
{
NerdDinners nerdDinners = new NerdDinners();

// Arrange
Mock.Arrange(() => nerdDinners.Dinners).ReturnsCollection(FakeDinners());

// Act
var query = from d in nerdDinners.Dinners
where d.DinnerID == 1
select d;

// Assert
Assert.AreEqual(1, query.Count());
Assert.AreEqual(1, query.First().DinnerID);
}
{{endregion}}

## Returning A Fake Collection with Future Mocking

In this example we will return the same fake collection.

#### __[C#]__
#### __[C#]__

{{region EntityFramework#FakeDinnersReturn}}
{{region EntityFramework#FakeDinnersReturn}}
public IList<Dinner> FakeDinners()
{
List<Dinner> fakeDin = new List<Dinner>
{
new Dinner { Address = "1 Microsoft way", DinnerID = 1, EventDate =DateTime.Now, HostedBy = "Telerik" , Title = "Telerik Dinner"}
};
return fakeDin;
}
{{endregion}}
{
List<Dinner> fakeDin = new List<Dinner>
{
new Dinner { Address = "1 Microsoft way", DinnerID = 1, EventDate =DateTime.Now, HostedBy = "Telerik" , Title = "Telerik Dinner"}
};

return fakeDin;
}
{{endregion}}

To assure that the instance does not matter during the __Act__ phase we will make a repository class:

#### __[C#]__

{{region EntityFramework#DinnersRepository}}
public class DinnerRepository
{
public Dinner GetById(int dinnerId)
{
NerdDinners nerdDinners = new NerdDinners();
var query = from d in nerdDinners.Dinners
where d.DinnerID == 1
select d;
return query.First();
}
}
{{endregion}}
#### __[C#]__

{{region EntityFramework#DinnersRepository}}
public class DinnerRepository
{
public Dinner GetById(int dinnerId)
{
NerdDinners nerdDinners = new NerdDinners();
var query = from d in nerdDinners.Dinners
where d.DinnerID == 1
select d;

return query.First();
}
}
{{endregion}}

As you see, in the test below we are acting with a `new DinnerRepository()`, but still we are meeting the expectations and the test passes. This behavior is known and expected in [Future Mocking]({%slug justmock/advanced-usage/future-mocking%}).

> Note that when you use `ReturnsCollection()` you must be using the `Telerik.JustMock.Helpers;` namespace.
#### __[C#]__
#### __[C#]__

{{region EntityFramework#FutureMockingCollectionReturn}}
[TestMethod]
public void ShouldReturnFakeCollectionForFutureInstance()
{
NerdDinners nerdDinners = new NerdDinners();

{{region EntityFramework#FutureMockingCollectionReturn}}
[TestMethod]
public void ShouldReturnFakeCollectionForFutureInstance()
{
NerdDinners nerdDinners = new NerdDinners();

Mock.Arrange(() => nerdDinners.Dinners).IgnoreInstance().ReturnsCollection(FakeDinners());

Assert.AreEqual(1, new DinnerRepository().GetById(1).DinnerID);
}
{{endregion}}
Mock.Arrange(() => nerdDinners.Dinners).IgnoreInstance().ReturnsCollection(FakeDinners());

Assert.AreEqual(1, new DinnerRepository().GetById(1).DinnerID);
}
{{endregion}}

## Faking the Add of an Entity

In the next example we will __Arrange__ the calling of the `Add()` method to actually add an item to a previously created local collection.

#### __[C#]__
{{region EntityFramework#FakingAdd}}
[TestMethod]
public void ShouldReturnFakeCollectionForFutureInstance()
{
NerdDinners nerdDinners = new NerdDinners();
Mock.Arrange(() => nerdDinners.Dinners).IgnoreInstance().ReturnsCollection(FakeDinners());
Assert.AreEqual(1, new DinnerRepository().GetById(1).DinnerID);
}
{{endregion}}
#### __[C#]__

{{region EntityFramework#FakingAdd}}
[TestMethod]
public void ShouldReturnFakeCollectionForFutureInstance()
{
NerdDinners nerdDinners = new NerdDinners();

Mock.Arrange(() => nerdDinners.Dinners).IgnoreInstance().ReturnsCollection(FakeDinners());

Assert.AreEqual(1, new DinnerRepository().GetById(1).DinnerID);
}
{{endregion}}

Here are the steps:

Expand All @@ -185,5 +183,5 @@ Here are the steps:
1. Arrange that the `SaveChanges()` method is doing nothing.
1. Act by calling `Add(dinner)` and `SaveChanges()`.
1. Verify that:
* the collection has exactly *one* item
* this item is exactly the object from *step 2.*
* the collection has exactly *one* item
* this item is exactly the object from *step 2.*

0 comments on commit 3a2fda3

Please sign in to comment.