How to use "Pex and Moles" library with Entity Framework? - unit-testing

This is a tough one because not too many people use Pex & Moles or so I think (even though Pex is a really great product - much better than any other unit testing tool)
I have a Data project that has a very simple model with just one entity (DBItem). I've also written a DBRepository within this project, that manipulates this EF model. Repository has a method called GetItems() that returns a list of business layer items (BLItem) and looks similar to this (simplified example):
public IList<BLItem> GetItems()
{
using (var ctx = new EFContext("name=MyWebConfigConnectionName"))
{
DateTime limit = DateTime.Today.AddDays(-10);
IList<DBItem> result = ctx.Items.Where(i => i.Changed > limit).ToList();
return result.ConvertAll(i => i.ToBusinessObject());
}
}
So now I'd like to create some unit tests for this particular method. I'm using Pex & Moles. I created my moles and stubs for my EF object context.
I would like to write parametrised unit test (I know I've first written my production code, but I had to, since I'm testing Pex & Moles) that tests that this method returns valid list of items.
This is my test class:
[PexClass]
public class RepoTest
{
[PexMethod]
public void GetItemsTest(ObjectSet<DBItem> items)
{
MEFContext.ConstructorString = (#this, name) => {
var mole = new SEFContext();
};
DBRepository repo = new DBRepository();
IList<BLItem> result = repo.GetItems();
IList<DBItem> manual = items.Where(i => i.Changed > DateTime.Today.AddDays(-10));
if (result.Count != manual.Count)
{
throw new Exception();
}
}
}
Then I run Pex Explorations for this particular parametrised unit test, but I get an error path bounds exceeded. Pex starts this test by providing null to this test method (so items = null). This is the code, that Pex is running:
[Test]
[PexGeneratedBy(typeof(RepoTest))]
[Ignore("the test state was: path bounds exceeded")]
public void DBRepository_GetTasks22301()
{
this.GetItemsTest((ObjectSet<DBItem>)null);
}
This was additional comment provided by Pex:
The test case ran too long for these inputs, and Pex stopped the analysis. Please notice: The method Oblivious.Data.Test.Repositories.TaskRepositoryTest.b__0 was called 50 times; please check that the code is not stuck in an infinite loop or recursion. Otherwise, click on 'Set MaxStack=200', and run Pex again.
Update attribute [PexMethod(MaxStack = 200)]
Question
Am I doing this the correct way or not? Should I use EFContext stub instead? Do I have to add additional attributes to test method so Moles host will be running (I'm not sure it does now). I'm running just Pex & Moles. No VS test or nUnit or anything else.
I guess I should probably set some limit to Pex how many items should it provide for this particular test method.

Moles is not designed to test the parts of your application that have external dependencies (e.g. file access, network access, database access, etc). Instead, Moles allows you to mock these parts of your app so that way you can do true unit testing on the parts that don't have external dependencies.
So I think you should just mock your EF objects and queries, e.g., by creating in-memory lists and having query methods return fake data from those lists based on whatever criteria is relevant.

I am just getting to grips with pex also ... my issues surrounded me wanting to use it with moq ;)
anyway ...
I have some methods similar to your that have the same problem. When i increased the max they went away. Presumably pex was satisfied that it had sufficiently explored the branches. I have methods where i have had to increase the timeout on the code contract validation also.
One thing that you should probably be doign though is passing in all the dependant objects as parameters ... ie dont instantiate the repo in the method but pass it in.
A general problem you have is that you are instantiating big objects in your method. I do the same in my DAL classes, but then i am not tryign to unit test them in isolation. I build up datasets and use this to test my data access code against.
I use pex on my business logic and objects.
If i were to try and test my DAL code id have to use IOC to pass the datacontext into the methods - which would then make testing possible as you can mock the data context.

You should use Entity Framework Repository Pattern: http://www.codeproject.com/KB/database/ImplRepositoryPatternEF.aspx

Related

Should I unit test classes which extend Sonata BaseEntityManager class?

Here is part of the code which extends BaseEntityManager:
namespace Vop\PolicyBundle\Entity;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\Common\Persistence\ObjectRepository;
use Sonata\CoreBundle\Model\BaseEntityManager;
class AdditionalInsuredTypeManager extends BaseEntityManager
{
/**
* #param int $productId
*
* #return ArrayCollection
*/
public function getProductInsuredTypes($productId = null)
{
$repository = $this->getRepository();
$allActiveTypes = $repository->findAllActive();
// other code
}
/**
* #return AdditionalInsuredTypeRepository|ObjectRepository
*/
protected function getRepository()
{
return parent::getRepository();
}
}
And here I am trying to write a unit test:
public function testGetProductInsuredTypes()
{
$managerRegistry = $this->getMockBuilder(\Doctrine\Common\Persistence\ManagerRegistry::class)
->getMock();
$additionalInsuredTypeManager = new AdditionalInsuredTypeManager(
AdditionalInsuredTypeManager::class,
$managerRegistry
);
$additionalInsuredTypeManager->getProductInsuredTypes(null);
}
What are the problems:
I am mocking ManagerRegistry, but I have learned that I should not mock what I do not own. But this is required parameter for constructor.
I am getting error:
Unable to find the mapping information for the class Vop\PolicyBundle\Entity\AdditionalInsuredTypeManager. Please check the 'auto_mapping' option (http://symfony.com/doc/current/reference/configuration/doctrine.html#configuration-overview) or add the bundle to the 'mappings' section in the doctrine configuration.
/home/darius/PhpstormProjects/vop/vendor/sonata-project/core-bundle/Model/BaseManager.php:54
/home/darius/PhpstormProjects/vop/vendor/sonata-project/core-bundle/Model/BaseManager.php:153
/home/darius/PhpstormProjects/vop/src/Vop/PolicyBundle/Entity/AdditionalInsuredTypeManager.php:46
/home/darius/PhpstormProjects/vop/src/Vop/PolicyBundle/Entity/AdditionalInsuredTypeManager.php:21
/home/darius/PhpstormProjects/vop/src/Vop/PolicyBundle/Tests/Unit/Entity/AdditionalInsuredTypeManagerTest.php:22
I do not know how to fix this error, but this really has to do something with extending that BaseEntityManager I assume.
I see the error is caused by this line:
$repository = $this->getRepository();
I cannot even inject the repository from the constructor, because parent constructor has no such parameter.
There is very little amout of information about testing:
https://sonata-project.org/bundles/core/master/doc/reference/testing.html
I can not tell you whether it's useful to test your repositories, neither can I give you pointers for your error other than that you should most likely not extend doctrine's entity manager. If anything use a custom EntityRepository or write a service in which you inject the EntityManager (or better the EntityRegistry):
class MyEntityManager
{
private $entityManager;
public function __construct(EntityManager $entityManager)
{
$this->entityManager = $entityManager;
}
public function getProductInsuredTypes($productId = null)
{
$repository = $this->entityManager->getRepository(Product::class);
$allActiveTypes = $repository->findAllActive();
// other code
}
}
What I can give you is an explanation how I approach testing repositories:
I think unit tests, especially with mocks, seem a bit wasteful. They only tie you to the current implementation and since anything of relevance is mocked out you will most likely not test any behavior.
What might be useful is doing functional tests where you provide a real database connection and then perform a query against the repository to see if it really returns the expected results. I usually do this for more complex queries or when using advanced doctrine features like native queries with a custom ResultsetMap. In this case you would not mock the EntityManager and instead would use Doctrine's TestHelper to create an in memory sqlite-database. This can look something like this:
protected $entityManager;
protected function setUp()
{
parent::setUp();
$config = DoctrineTestHelper::createTestConfiguration();
$config->setNamingStrategy(new UnderscoreNamingStrategy());
$config->setRepositoryFactory(new RepositoryFactory());
$this->entityManager = DoctrineTestHelper::createTestEntityManager($config);
}
The downside is, that you will manually have to register custom types and listeners which means the behavior might differ from your production configuration. Additionally you are still tasked with setting up the schema and providing fixtures for your tests. You will also most likely not use SQLite in production so this is another deviation. The benefit is that you will not have to deal with clearing your database between runs and can easily parallelize running tests, plus it's usually faster and easier than setting up a complete test database.
The final option is somewhat close to the previous one. You can have a test database, which you define in your parameters, environment variables or a config_test.yml, you can then bootstrap the kernel and fetch the entity manager from your DI-container. Symfony's WebTestCase can be used as a reference for this approach.
The downside is, that you will have to boot your kernel and make sure to have separate database setups for development, production and testing to ensure your test data does not mess up anything. You will also have to setup your schema and fixtures and additionally you can easily run into issues where tests are not isolated and start being flakey, e.g. when run in different order or when running only parts of your test suite. Obviously since this is a full integration test through your bootstrapped application the performance footprint compared to a unit test or smaller functional test is noticeably higher and application caches might give you additional headaches.
As a rule of thumb:
I trust Doctrine when doing the most basic kind of queries and therefore do not test repositories for simple find-methods.
When I write critical queries I prefer testing them indirectly on higher layers, e.g. ensure in an acceptance test that the page displays the information.
When I encounter issues with repositories or need tests on lower layers I start with functional tests and then move on to integration tests for repositories.
tl;dr
Unit tests for repositories are mostly pointless (in my opinion)
Functional tests are good for testing simple queries in isolation with a reasonable amount of effort, should you need them.
Integration tests ensure the most production like behavior, but are more painful to setup and maintain

Unit Testing and Integration Testing examples

I have created following four tests in a Test class that tests a findCompany() method of a CompanyService.
#Test
public void findCompany_CompanyIdIsZero() {
exception.expect(IllegalArgumentException.class);
companyService.findCompany(0);
}
#Test
public void findCompany_CompanyIdIsNegative() {
exception.expect(IllegalArgumentException.class);
companyService.findCompany(-100);
}
#Test
public void findCompany_CompanyIdDoesntExistInDatabase() {
Company storedCompany = companyService.findCompany(100000);
assertNull(storedCompany1);
}
#Test
public void findCompany_CompanyIdExistsInDatabase() {
Company company = new Company("FAL", "Falahaar");
companyService.addCompany(company);
Company storedCompany1 = companyService.findCompany(company.getId());
assertNotNull(storedCompany1);
}
My understanding says that the first three of these are unit tests. They test the behavior of the findCompany() method, checking how the method will respond on different inputs.
The fourth test, though placed in the same class, actually seems to be an integration test to me. It requires a Company to be added to the database first, so that it can be found later on. This introduces external dependencies - addCompany() and database.
Am I going right? If yes, then how should I unit test finding an existing object? Just mock the service to "find" one? I think that kills the intent of the test.
I appreciate any guidance here.
I look at it this way: the "unit" you are testing here is the CompanyService. In this sense all of your tests look like unit tests to me. Underneath your service, though, there may be another service (you mention a database) that this test is also exercising? This could start to blur the lines with integration testing a bit, but you have to ask yourself if it matters. You could stub out any such underlying service, and you may want to if:
The underlying service is slow to set up or use, making your unit tests too slow.
You want to be sure the behaviour of this test is unaffected by the underlying service - i.e. this test should only fail if there is a bug in CompanyService.
In my experience, provided the underlying service is fast enough I don't worry too much about my unit test relying on it. I don't mind a bit of integration leaking into my unit tests, as it has benefits (more integration coverage) and rarely causes a problem. If it does cause problems you can always come back to it and add stubbing to improve the isolation.
[1,2,3,4] could be unit-based (mocked | not mocked) and integration-based tests. It depends what you want to test.
Why use mocking? As Jason Sankey said ...test only service tier not underlaying tier.
Why use mocking? Your bussiness logic can have most various forms. So you can write several test for one service method, eg. create person (no address - exception, no bank account - exception, person does not have filled not-null attributes - exception).
Can you imagine that each test requested database in order to test all possibility exception states (no adress, no bank account etc.)? There is too much work to fill database in order to test all exception states. Why not to use mocked objects which eg. act like 'crippled' objects which do not contains expected values. Each test construct own 'crippled' mock object.
Mocking various states === your test will be simply as possible because each test method will be test only one state. These test will be clear and easy to understand and maintance. This is one of goals which I want to reach if I write a test.

Unit testing Code which use API

I have this simple method which calls the TFS (Team foundation server) API to get WorkItemCollection object. I have just converted in to an entity class and also added it in cache. As you can see this is very simple.
How should i unit test this method. Only the important bit it does is calls TFS API. Is it worth testing such methods? If yes then how should we test it?
One way I can think is I can mock call to Query.QueryWorkItemStore(query) and return an object of type “WorkItemCollection” and see finally this method converts “WorkItemCollection” to List. And check if it was added to cache or not.
Also as I am using dependency injection pattern her so I am injecting dependency for
cache
Query
Should I only pass dependency of mocked type (Using MOQ) or I should pass proper class type.
public virtual List<Sprint> Sprint(string query)
{
List<Sprint> sprints =
Cache.Get<List<Sprint>>(query);
if (sprints == null)
{
WorkItemCollection items =
Query.QueryWorkItemStore(query);
sprints = new List<Sprint>();
foreach (WorkItem i in items)
{
Sprint sprint = new Sprint
{
ID = i.Id,
IterationPath = i.IterationPath,
AreaPath = i.AreaPath,
Title = i.Title,
State = i.State,
Goal = i.Description,
};
sprints.Add(sprint);
}
Cache.Add(sprints, query,
this.CacheExpiryInterval);
}
return sprints;
}
Should I only pass dependency of mocked type (Using MOQ) or I should pass proper class type.
In your unit tests, you should pass a mock. There are several reasons:
A mock is transparent: it allows you to check that the code under test did the right thing with the mock.
A mock gives you full control, allowing you to test scenarios that are difficult or impossible to create with the real server (e.g. throw IOException)
A mock is predictable. A real server is not - it may not even be available when you run your tests.
Things you do on a mock don't influence the outside world. You don't want to change data or crash the server by running your tests.
A test with mocks is faster. No connection to the server or real database queries have to be made.
That being said, automated integration tests which include a real server are also very useful. You just have to keep in mind that they will have lower code coverage, will be more fragile, and will be more expensive to create/run/maintain. Keep your unit tests and your integration tests separate.
edit: some collaborator objects like your Cache object may also be very unit-test friendly. If they have the same advantages as that of a mock that I list above, then you don't need to create a mock. For example, you typically don't need to mock a collection.

Can I unit test a method that makes Sitecore context calls?

I'm working on a web application that is built over Sitecore CMS. I was wondering if we could unit test for example a method that takes some data from Sitecore makes some processing with it and spits out a result. I would like to test all the logic within the method via a unit test.
I pretty confused after searching the internet wide and deep. Some say that this kind of testing is actually integration testing and not unit testing and I should test only the code that has no Sitecore calls, others say that this is not possible because the Sitecore context would be missing.
I would like to ask for your help experienced fellow programmers:
Can I unit test a method that contains Sitecore calls ? If YES, how ? If NO, why ? Is there any workaround ?
The project is at its beginning, so there will be no problem in choosing between unit testing frameworks such as MSTest or Nunit, if it is the case that the solution is related to the unit testing framework of choice.
It's pretty hard to find out anything about Sitecore without providing email and living through the sales pitch, so I'll just provide a generic approach on how to do something like this.
First and foremost, you assume that the Sitecore API is guaranteed to work - i.e. it's a framework - and you don't unit test it. You should be unit testing your interactions with it.
Then, download MOQ and read the quick start on how to use it. This is my preferred mocking framework. Feel free to use other frameworks if you wish.
Hopefully, Sitecore API provides a way for you to create data objects without dealing with persistence - i.e. to simply create a new instance of whatever it is you are interested in. Here is my imaginary API:
public class Post {
public string Body {get;set;}
public DateTime LastModified {get;set;}
public string Title {get;set;}
}
public interface ISiteCorePosts {
public IEnumerable<Post> GetPostsByUser(int userId);
}
In this case unit testing should be fairly easy. With a bit of Dependency Injection, you can inject the SiteCore interfaces into your component and then unit test it.
public class MyPostProcessor {
private readonly ISiteCorePosts m_postRepository;
public MyPostProcessor(ISiteCorePosts postRepository) {
m_postRepository = postRepository;
}
public void ProcessPosts(int userId) {
var posts = m_postRepository.GetPostsByUser(userId);
//do something with posts
}
}
public class MyPostProcessorTest {
[TestMethod]
ProcessPostsShouldCallGetPostsByUser() {
var siteCorePostsMock = new Mock<ISiteCorePosts>();
//Sets up the mock to return a list of posts when called with userId = 5
siteCorePostsMock.Setup(m=>m.GetPostsByUser(5)).Returns(new List<Post>{/*fake posts*/});
MyPostProcessor target = new MyPostProcessor(siteCorePostsMock.Object);
target.ProcessPosts(5);
//Verifies that all setups are called
siteCorePostsMock.VerifyAll();
}
}
If ISiteCorePosts is not, in fact, an interface and is a concrete class whose methods are not virtual and thus cannot be mocked, you will need to use Facade pattern to wrap the SiteCore interaction to make it more testing friendly.
public class SiteCorePostsFacade {
SiteCorePosts m_Posts = new SiteCorePosts();
//important - make this method virtual so it can be mocked without needing an interface
public virtual IEnumerable<Post> GetPostsByUser(int userId) {
return m_Posts.GetPostsByUser(userId);
}
}
You then proceed to use SiteCorePostsFacade as though it was an interface in the previous example. Good thing about MOQ is that it allows you to mock concrete classes with virtual methods, not just interfaces.
With this approach, you should be able to inject all sorts of data into your application to test all interactions with SiteCore API.
we have used a custom WebControl placed on a WebForm for our integration tests some years now, which wraps the NUnit Test Suite runner functionality much like the NUnit GUI. It show a pretty grid of executed tests with links to fixtures and categories to execute specific tests. Its created much like described here http://adeneys.wordpress.com/2010/04/13/new-technique-for-unit-testing-renderings-in-sitecore/ (the custom test runner part). Our implementation can also return raw NUnit xml for further processing by for example a build server.
I've tried MSTest a while back and it also works when specified that it should launch a WebDev / IIS site to test. It works but is extremely slow compared to above solution.
Happy testing!
Short answer:
You need to mock calls to SiteCore CMS.
Long answer:
I am not aware about SiteCore CMS. But, from your question looks like it is something that is external to your application. Components external to your system should always be used via interface. This has two benefits:
If you want to use another CMS system, you can easily do as your application is just talking to an interface.
It helps you with behavior testing by mocking the interface.
The code you write is your responsibility and hence you should only unit test that piece of code. Your unit tests should ensure that your code calls appropriate SiteCode CMS methods in various scenarios (behavior tests). You can do this using mocking. I use moq for mocking.
As tugga said, it depends upon how tightly the code you want to test is coupled to SiteCore. If it's something like:
SomeSiteCoreService siteCoreDependency = new SomeSiteCoreService()
Then this would be very difficult to test. If SiteCore provides you an interface, then you have more flexibility to unit test it. You could pass the implementation into your method either (contstructor, class property, or method parameter) and then you can send in a fake implementation of that service.
If they do not provide you with an interface, then you have to do a little more work. You would write an adapter interface of your own and the default implementation would delegate to the 3rd party dependency.
public interface ICMSAdapter{
void DoSomethingWithCMS()
}
public class SiteCoreCMSAdapter: ICMSAdapter{
SiteCoreService _cms = new SiteCoreService();
public void DoSomethingWithCMS(){
_cms.DoSomething();
}
That keeps your 3rd party dependencies at arms length and provides seams to all sorts of cool things, like unit tests and you do interception style architecture and do your own thing before and after the call.
}
I was able to get unit tests to interact with sitecore api in VS 2015. The same test throws a StackOverflow exception when run in VS 2012.
For example, this method call runs fine in VS2015 but not VS2015:
Context.SetActiveSite("mysite");
quick note: this assumes you have a site named mysite setup in your config file

MEF and unit testing with NUnit

A few weeks ago I jumped on the MEF (ComponentModel) bandwagon, and am now using it for a lot of my plugins and also shared libraries. Overall, it's been great aside from the frequent mistakes on my part, which result in frustrating debugging sessions.
Anyhow, my app has been running great, but my MEF-related code changes have caused my automated builds to fail. Most of my unit tests were failing simply because the modules I was testing were dependent upon other modules that needed to be loaded by MEF. I worked around these situations by bypassing MEF and directly instantiating those objects.
In other words, via MEF I would have something like
[Import]
public ICandyInterface ci { get; set; }
and
[Export(typeof(ICandyInterface))]
public class MyCandy : ICandyInterface
{
[ImportingConstructor]
public MyCandy( [Import("name_param")] string name) {}
...
}
But in my unit tests, I would just use
CandyInterface MyCandy = new CandyInterface( "Godiva");
In addition, the CandyInterface requires a connection to a database, which I have worked around by just adding a test database to my unit test folder, and I have NUnit use that for all of the tests.
Ok, so here are my questions regarding this situation:
Is this a Bad Way to do things?
Would you recommend composing parts in [SetUp]
I haven't yet learned how to use mocks in unit testing -- is this a good example of a case where I might want to mock the underlying database connection (somehow) to just return dummy data and not really require a database?
If you've encountered something like this before, can you offer your experience and the way you solved your problem? (or should this go into the community wiki?)
It sounds like you are on the right track. A unit test should test a unit, and that's what you do when you directly create instances. If you let MEF compose instances for you, they would tend towards integration tests. Not that there's anything wrong with integration tests, but unit tests tend to be more maintainable because you test each unit in isolation.
You don't need a container to wire up instances in unit tests.
I generally recommend against composing Fixtures in SetUp, as it leads to the General Fixture anti-pattern.
It is best practice to replace dependencies with Test Doubles. Dynamic mocks is one of the more versatile ways of doing this, so definitely something you should learn.
I agree that creating the DOCs manually is much better than using MEF composition container to satisfy imports, but regarding the note 'compositing fixtures in setup leads to the general fixture anti pattern' - I want to mention that that's not always the case.
If you’re using the static container and satisfy imports via CompositionInitializer.SatisfyImports you will have to face the general fixture anti pattern as CompositionInitializer.Initialize cannot be called more than once. However, you can always create CompositionContainer, add catalogs, and call SatisyImportOnce on the container itself. In that case you can use a new CompositionContainer in every test and get away with facing the shared/general fixture anti pattern
I blogged on how to do unit tests (not nunit but works just the same) with MEF.
The trick was to use a MockExportProvider and i created a test base for all my tests to inherit from.
This is my main AutoWire function that works for integration and unit tests:
protected void AutoWire(MockExportProvider mocksProvider, params Assembly[] assemblies){
CompositionContainer container = null;
var assCatalogs = new List<AssemblyCatalog>();
foreach(var a in assemblies)
{
assCatalogs.Add(new AssemblyCatalog(a));
}
if (mocksProvider != null)
{
var providers = new List<ExportProvider>();
providers.Add(mocksProvider); //need to use the mocks provider before the assembly ones
foreach (var ac in assCatalogs)
{
var assemblyProvider = new CatalogExportProvider(ac);
providers.Add(assemblyProvider);
}
container = new CompositionContainer(providers.ToArray());
foreach (var p in providers) //must set the source provider for CatalogExportProvider back to the container (kinda stupid but apparently no way around this)
{
if (p is CatalogExportProvider)
{
((CatalogExportProvider)p).SourceProvider = container;
}
}
}
else
{
container = new CompositionContainer(new AggregateCatalog(assCatalogs));
}
container.ComposeParts(this);
}
More info on my post: https://yoavniran.wordpress.com/2012/10/18/unit-testing-wcf-and-mef/