https://github.com/timostamm/datafixtures
.NET Datafixtures for Unit Tests
https://github.com/timostamm/datafixtures
dotnet entityframework fixture-loader fixtures unittest
Last synced: 5 months ago
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.NET Datafixtures for Unit Tests
- Host: GitHub
- URL: https://github.com/timostamm/datafixtures
- Owner: timostamm
- License: mit
- Created: 2017-09-26T13:43:48.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2017-09-27T07:28:47.000Z (over 8 years ago)
- Last Synced: 2025-01-03T10:24:27.757Z (about 1 year ago)
- Topics: dotnet, entityframework, fixture-loader, fixtures, unittest
- Language: C#
- Size: 7.52 MB
- Stars: 0
- Watchers: 3
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Datafixtures
.NET Datafixtures for Unit Tests
Test fixtures can be used to setup a certain environment state - usually a database. They make unit testing easier because you can easily enforce a particular state neccessary to test your code.
Fixtures should be able to depend on each other, so that each fixture can focus on its own data.
This library provides a Fixture base class and a fixture loader that takes care of dependencies.
##### Defining and loading simple fixtures
A simple fixture extends `Fixture` and overrides `DoLoad()`:
```C#
class StartOfUnixTime : Fixture
{
protected override DateTime DoLoad()
{
return new DateTime(1970, 1, 1, 0, 0, 0, DateTimeKind.Utc);
}
}
```
To use this fixture, you need to load it:
```C#
var loader = new FixtureLoader();
var unixStart = loader.Add();
loader.Load();
// The data generated by the fixture is available via the property "Result".
Assert.AreEqual(1970, unixStart.Result.Year);
```
To make a fixture depend on another fixture, simply reference it as a constructor argument.
```C#
class UnixStartMessage : Fixture
{
private readonly StartOfUnixTime start;
public UnixStartMessage(StartOfUnixTime start)
{
this.start = start;
}
protected override string DoLoad()
{
// You can access the result of the StartOfUnixTime
// fixture via its Result property
return "hello world, it is " + start.Result.Year;
}
}
```
When loading this fixture, the dependant fixtures are loaded automatically. You just need to load the fixture you are actually using.
```C#
var loader = new FixtureLoader();
var msg = loader.Add();
loader.Load();
Assert.AreEqual("hello world, it is 1970", msg.Result);
```
##### Using fixtures with the EntityFramework
In a fixture, you probably want to add an entity to your db context and save the changes. The db context is just another dependency and can simply be injected as a constructor argument.
```C#
class FirstStudent : Fixture
{
private readonly SchoolDbContext schoolDb;
public UnixStartMessage(SchoolDbContext schoolDb)
{
this.schoolDb = schoolDb;
}
protected override Student DoLoad()
{
var first = new Student()
{
StudentName = "Donald Knuth"
};
schoolDb.Students.AddObject( first );
return first;
}
}
```
##### Clearing and initializing the database
Loading Database fixtures has a few implications. If you want your database to be in a repeatable state, you have to empty it first. You can use the utility class EntityFixtures to drop the entire database, initialize it, and load your fixtures:
```C#
var schoolDb = new SchoolDbContext();
FixtureLoader loader = EntityFixtures.DropCreateDatabase(scoolDb)
var first = loader.add();
loader.load();
// now you have a clean database with the first student
System.Diagnostics.Trace.WriteLine("First student: " + first.Result.StudentName); // => "First student: Donald Knuth"
```
##### Drop the database ?!?
You should use a LocalDB for your unittests. `EntityFixtures.DropCreateDatabase()` actually throws an exception if you do not, but in any case: use your own brain.
##### Injecting other dependencies
If you have a look at `EntityFixtures.DropCreateDatabase()`, it just calls `FixtureLoader.RegisterService()` with your DbContext, and thereby making it available for constructor injection:
```C#
loader.RegisterService(context);
```
You are of course free to register and use other dependencies.