I've been playing with ADO.NET Entity Framework lately, and I find that it suits my needs for a project I'm developing. I also find cool its non-invasive nature.
After generating a data model from an existing database you are faced with the task of integrating the generated model and your business logic. More specifically, I'm used to integration-test my classes that interact with the data store via mocks/stubs of the DAL interfaces. The problem is that you cannot do this using the ADO.NET Entity Framework because the entities it generates are simple classes with no interface.
The question is: how do I apply a TDD approach to the development of an application that uses ADO.NET Entity Framework? Is this even possible or should I migrate to another DAL-generation toolset?
One of the big critiques against the Entity Framework has been that it is inherently hard to test, for example in the ALT.Net Vote of No Confidence that gef quoted.
Here is a blog post discussing how to get around this, and be able to test your code without hitting the database, when using Entity Framework.
If testability is a big concern, you might want to look at another ORM framework, such as NHibernate, at least until Entity Framework 2.0 is released.
Although, the original question has been answered, I feel like I might add something:
I am currently using the Entity Framework 4.0 on an intranet site I'm building. I am able to test everything in my business logic and controllers without a database connection using the POCO support that has been added.
Although, the POCO's can be generated from the new t4 template included in VS 2010, something that I haven't been able to find in VS 2010 is a t4 template for generating your object context (the object context basically works as a built in unit of work for EF and is essential for mapping your EF objects to POCOs). Luckily Joachim Lykke Andersen in his blog post Entity Framework 4.0 Beta 1 – POCO, ObjectSet, Repository and UnitOfWork wrote a t4 template for generating it and it has been very helpful. If you pursue a solution using the EF4 that is testable without a database connection I highly recommend implementing something similar to his solution which includes a generic repository, unit of work wrapper, and a unit of work factory. It has been very helpful.
Best of luck.
I agree that version 1 of the Entity Framework is a crime against design and it definitely got my vote of no confidence. I credit the EF product team though for acknowledging the failure and responding by opening up their design process to the community. The next release isn't going to be perfect, it might not even be ready for use in a production level application, but I think they're finally starting to understand what's important to those of use who know that bad design is bad business. That being said... I'm still suspicious. Continuous design-time feedback is new to these guys and I've read quite a few statements on the ADO.NET blog that raise bright, red flags. We'll see how it goes with the release of .NET 4.0.
They appear to be trying though:
Test-Driven Development Walkthrough with the Entity Framework 4.0
"The tight coupling of the persistence
infrastructure to the entity classes
largely eliminates the ability to
efficiently use very tight feedback
cycles on the business logic with
automated testing. In its current
state, EF entity classes cannot be
effectively unit tested independently
of the database.
The efficiency of automated unit
testing of behavioral objects is
largely a matter of how easy the
mechanics of test data setup are and
how quickly the tests can be executed.
Using the actual database will make
test data setup more laborious,
introduce data to satisfy relational
constraints that are not germane to
the test, and make test execution an
order of magnitude slower.
A team’s ability to do evolutionary
design and incremental delivery is
damaged by the Entity Framework’s
inattention to fundamental software
design principles like Separation of
Concerns."
Blatantly stolen from here:
http://efvote.wufoo.com/forms/ado-net-entity-framework-vote-of-no-confidence/
If you're looking specifically at DAL-generation tools you'll have a hard time integrating this with TDD. Most dal generation tools I know also generate your business objects and tightly couple them to the DAL making testing difficult.
You can look at OR-mapping tools like nHibernate and maybe Linq to sql that enable "persistance ignorance", you can define your business objects yourself and they have no links to the DAL or any other infrastructure code. This makes testing your business logic seperately from your database much easier. I found it also enables other scenario's like occasionally connected clients far better.
This answer has changed to "Yes, you can".
You can generate POCO and interfaces using customized T4 templates such as https://entityinterfacegenerator.codeplex.com/, then create mocking objects to test EF in and out without hitting the database.
Related
So, testing with Sitecore. It's a special topic and I've found allot of reading material regarding it already. (Sitecore Development Chapter 8, Alistair Deneys blog, NextDigital blog, iStern blog,...) but in most of these cases they're going with NUnit and custom test runners etc... The most useful (to me in my context) this far was the iStern blog for mocking out Sitecore using Microsoft Fakes. But is this really the way to go?
I'm surprised that with Hedgehog TDS system to integrate so deeply with TFS and be able to do CI in Sitecore development that there isn't more on how to utilize this system for setting up solid testing executed by TFS (yet).
We're gearing up for a large new project now that uses Sitecore to handle front-end user interaction where the data being used is 95% behind a WCF service. So this part can be easily tested and TDD developed. It's the last 5% (which sadly includes like the highest business value, being online payments) that resides within Sitecore that needs to be tested. Can we ever have enough intimate knowledge of sitecore to mock it out? I'd be inclined to think not... if so, how then do we run conclusive tests on our TFS CI build against sitecore?
Last but not least I get the feeling that the information currently to be found is getting a bit out of date perhaps (maily seeing the remarks on the NextDigital blog), does Sitecore 7 open new ways to tackle this issue?
For those who'd see this more as a philosophical rather then a technical question: There can only be one answer to this and that is a technical accurate definition of a method of using the Microsoft test framework that is capable of running in the TFS CI environment to test code written for Sitecore.
Is Microsoft Fakes the way to go? In my opinion, no. Microsoft fakes allows you to test code that is not designed to be testable. If you design you solution properly, a standard mocking framework should be sufficient.
Can we ever have enough intimate knowledge of sitecore to mock it out? This is kind of a trick question. Unless a third-party library was specifically designed for it and is something that you would consider a "stable dependency", you shouldn't try to mock it. Instead, wrap it with your own classes and abstractions and mock those.
Take a look at Synthesis and Glass Mapper. They are object-mapping frameworks that allow you to map Sitecore items to interfaces while maintaining page editor support. Glass, in particular has a wrapper around Sitecore.Context that can be mocked. Synthesis is supposed to be pretty testable as well, but I haven't tried it yet.
Using one of those mapping frameworks and a good SOLID design, you should be able to make most of your code testable. Just remember that the classes on the edges of your solution should be simple enough to not require testing.
I was in the exact same situation as you, IvanL, a few weeks ago. I wanted to test some of my business logic running against Sitecore 7 without a mocking framework. I managed to do it, but only in a very specific scenario. Unfortunately, I haven't published my prototype solution or the slides explaining it yet, but I'll explain the basics of what I did.
In Sitecore 7, the move towards querying against the index with the Sitecore.ContentSearch namespace and using LINQ opened up a way for me to very easily unit test with fake index data.
There are some unit test examples out there, as you've seen, that use mocking frameworks. However, the classes they mock are actually quite simple to fake out yourself. If you implement ISearchIndex, you really only need to implement the CreateSearchContext method in order to start returning an IQueryable to work with in your tests.
To implement CreateSearchContext, you will likely need to create a fake provider search context implementation that will do the GetQueryable implementation.
Once you have those two classes set up, you've essentially got your 'index' covered. Add a property onto it where you can set the data collection from the unit test and then make sure the context returns that data collection.
That will let you build up a fake index with whatever data POCOs you want, and then pass that through to your standard provider implementations that are running your business data.
The big thing to remember is that this only works for any code you may be writing that will use the new Sitecore 7 way of using LINQ and the IQueryable implementation. Older style code that is running using the Sitecore.Data.Item API still works the way it used to, and has the same limitations as before.
Update: The prototype I mentioned is now available for download: http://blog.nonlinearcreations.com/2014/02/sitecore-7-developers-quest-successful-unit-testing/
I currently have a project I've started with EF4, and am going back and adding in unit testing after the fact. I am using the EF4 POCO T4 templates with my model (database) first context. I am using generic repositories for my DAC logic, and unit of work pattern for persistence.
However, I'm running into some issues understanding how to mock up the ObjectContext/ObjectSet. I looked at using the FakeObjectSet<T> sample from this article, but it still leaves a few things out, such as auto-incrementing identities and transaction rollbacks.
So, I'm trying to find a good EF design that will still be fully unit testable.
My question is, does EF4.1 DbSet solve a lot of the issues w/ unit testing EF4? Are there any good comprehensive articles for designing EF4.1 solutions that are fully testable?
Also, keep in mind that I need a model-first solution.
Thanks in advance.
Fully simulating behavior of mocked layer is not point of unit testing. The point of unit testing is believing that mocked layer simply works. Unit test verifies the tested method not the mock. You will just verify that correct method on the mock were called and perhaps you will set up some callbacks for modifying passed data if your business logic expects some values. Example:
You have a business method inserting the record to the database and using the entity and its Id after insertion. The IObjectSet mock will be configured to:
Set expectation that AddObject was called only once - you can set the expected instance in the verification
You can define callback for AddObject to set Id to some value and use it later in the test
DbSet will not make any difference - it is just wrapper around ObjectSet with similar behavior. In my opinion there is no efficient way to make mocks behave as real EF. The effort needed for creating mock with behavior simulating EF + database will be much bigger then effort for your whole application! That will not be mock anymore it will be fake EF provider.
If you want to test your EF code (mapping, querying, persisting) and database behavior (like auto-increment, transactions, etc) you have to write integration tests. Here you have some related questions discussing repositories, unit of work and challenges with testing:
ASP.NET MVC3 and Entity Framework Code first architecture
Organizationally, where should I put common queries when using Entity Framework Code First?
If I'm having Data Access Layer (nHibernate) for example a class called UserProvider
and a Business Logic class UserBl, should I both test their methods SaveUser or GetUserById, or any other public method in DA layer which is called from BL layer. Is this a redundancy or a common practice to do?
Is it common to unit test DA layer, or that belongs to Integration test domain?
Is it better to have test database, or create database data during test?
Any help is appreciated.
There's no right answer to this, it really depends. Some people (e.g Roy Osherove) say you should only test code which has conditional logic (IF statements etc), which may or may not include your DAL. Some people (often those doing TDD) will say you should test everything, including the DAL, and aim for 100% code coverage.
Personally I only test it if it has logic in, so end up with some DAL methods tested and some not. Most of the time you just end up checking that your BL calls your DAL, which has some merit but I don't find necessary. I think it makes more sense to have integration tests which cover the app end-to-end, including the database, which covers things like GetUserById.
Either way, and you probably know this already, but make sure your unit tests don't touch an actual database. (No problem doing this, but that's an integration test not a unit test, as it takes a lot longer and involves complex setup, and should be run separately).
It is a good practice to write unit test for every layer, even the DAL.
I don't think running tests on the real db is a good idea, you might ruin important data. We used to set up a copy of the db for tests with just enough data in it to run tests on.
In our test project we had a special web.config file with test settings, like a ConnectionString to our test db.
In my experience it was helpful to test each layer on its own. Integrating it and test again. Integration test normally does not test all aspects. Sometimes if the Data Access Layer (I don't know nHibernate) is generated code or sort of generic code it looks like overkill. But I have seen it more than once that systematic testing pays off.
Is it redundancy? In my opinion it is not.
Is it common practice? Hard to tell. I would say no. I have seen it in some projects but not in all projects I worked in. Was often dependend on time/resources and mentality of the team / individiual developer.
Is it better to have test database, or create database data during test? This is quite a different question. Cannot be answered easily. Depends on your project. Create a new one is good but sometimes throws up unreal bugs (although bugs). It is depending on your project (product development or a proprietary development). Usually in an proprietary on site development a database gets migrated into from somewhere. So a second test is definitely needed with the migrated data. But this is rather at a system test level.
Unit testing the DAL is worth it as mentioned if there is logic in there, for example if using the same StoredProc for insert & update its worth knowing that an insert works, a subsequent call updates the previous and a select returns it and not a list. In your case SaveUser method probably inserts first time around and subsequently updates, its nice to know that this is whats being done at unit test stage.
If you're using a framework like iBatis or Hibernate where you can implement typehandlers its worth confirming that the handlers handle values in a way that's acceptable to your underlying DB.
As for testing against an actual DB if you use a framework like Spring you can avail of the supported database unit test classes with auto rollback of transactions so you run your tests and the DB is unaffected afterwards. See here for information. Others probably offer similiar support.
I'm working on a very large, data-intensive legacy application. Both the code base & database are massive in scale. A great deal of the business logic is spread across all of the tiers including in stored procedures.
Does anybody have any suggestions on how to begin applying "unit" tests (technically integration tests because they need to test across tiers for a single aspect of almost any given process) into the application in an efficient way? The current architecture does not easily support any type of injection or mocking. New code is being written to facilitate testing, but what about the legacy code? Because of the strong dependency on the data itself and business logic in the database, I'm currently using inline sql to find data to use for testing but these are time consuming. Creating views and/or stored procedures will not suffice.
What approaches have you taken (if applicable)? What worked? What didn't & why? Any suggestions would be appreciated. Thanks.
Get a copy of Working Effectively with Legacy Code by Michael Feathers. It is full of useful advice for working with large, untested codebases.
Another good book is Object Oriented Reengineering Patterns. Most of the book is not specific to object-oriented software. The full text is available for free download in PDF format.
From my own experience: try to...
Automate the build and deployment
Get the database schema into version control, if it isn't yet. Usually databases include reference data that the transactional code needs to exist before it can work. Get this under version control too. Tools like dbdeploy can help you easily rebuild a schema and reference data from a sequence of deltas.
Install a version of the database (and any other infrastructure services) onto your development workstation. This will let you work on the database without continually having to go through DBAs. It's also faster than using a schema on a shared server in a remote datacentre. All major commercial database servers have free (as in beer) development versions that work on Windows (if you're stuck in the unenviable situation of developing on Windows and deploying on Unix).
Before starting work on an area of the code, write end-to-end tests that roughly cover the behaviour of the area you're working on. An end-to-end test should exercise the system from outside -- by controlling its user interface or interacting through network services -- so you won't need to change the code to put it into place. It will act as an (imperfect) regression test and give you more confidence to refactor the internals of the system towards a structure that is easier to unit test.
If there are manual test plans, read them and see what can be automated. Most manual test plans are almost entirely scripted and so are low-hanging fruit for automation
Once you've got end-to-end tests coverage, refactor the code into more loosely coupled units as you modify and/or extend it. Surround those units with unit tests.
Things to avoid:
Copying data from the production database into the environment you use for automated testing. This will make your tests unpredictable. Sure, run the system against a copy of production data, but use that for exploratory testing, not regression testing.
Rolling back transactions at the end of tests to isolate tests from one another. This will not test behaviour that only happens when transactions are committed, and will throw away data that is valuable for diagnosing test failures. Instead, tests should ensure the database is in a known initial state when they start.
Creating a "tiny" data set for tests to run against. This makes tests hard to understand because they cannot be read as a single unit. The "tiny" data set soon grows very large as you add tests for different scenarios. Instead, tests can insert data into the database to set up the test-fixture.
“Testing Legacy Application Modernization,” highlights:
High level overview of how tests are created in AscentialTest
Ways to convert the legacy objects to the new platform Components of Object definition
How to ensure that the modernized version of the application produces the same results
For more details on usage of testing legacy application, do check here:
http://application-management.cioreview.com/whitepaper/testing-legacy-application-modernization-wid-529.html
As mentioned before, there are some very good books out there. Highly recommended to take a look at Working Effectively with Legacy Code.
Something you could do is following a data driven approach, observe your application and introduce tests where you have more “pain”. A semi-deterministic approach you might find useful: https://link.medium.com/zY9Tysfne9
Unit testing and ASP.NET web applications are an ambiguous point in my group. More often than not, good testing practices fall through the cracks and web applications end up going live for several years with no tests.
The cause of this pain point generally revolves around the hassle of writing UI automation mid-development.
How do you or your organization integrate best TDD practices with web application development?
Unit testing will be achievable if you separate your layers appropriately. As Rob Cooper implied, don't put any logic in your WebForm other than logic to manage your presentation. All other stuff logic and persistence layers should be kept in separate classes and then you can test those individually.
To test the GUI some people like selenium. Others complain that is a pain to set up.
I layer out the application and at least unit test from the presenter/controller (whichever is your preference, mvc/mvp) to the data layer. That way I have good test coverage over most of the code that is written.
I have looked at FitNesse, Watin and Selenium as options to automate the UI testing but I haven't got around to using these on any projects yet, so we stick with human testing. FitNesse was the one I was leaning toward but I couldn't introduce this as well as introducing TDD (does that make me bad? I hope not!).
This is a good question, one that I will be subscribing too :)
I am still relatively new to web dev, and I too am looking at a lot of code that is largely untested.
For me, I keep the UI as light as possible (normally only a few lines of code) and test the crap out of everything else. At least I can then have some confidence that everything that makes it to the UI is as correct as it can be.
Is it perfect? Perhaps not, but at least it as still quite highly automated and the core code (where most of the "magic" happens) still has pretty good coverage..
I would generally avoid testing that involves relying on UI elements. I favor integration testing, which tests everything from your database layer up to the view layer (but not the actual layout).
Try to start a test suite before writing a line of actual code in a new project, since it's harder to write tests later.
Choose carefully what you test - don't mindlessly write tests for everything. Sometimes it's a boring task, so don't make it harder. If you write too many tests, you risk abandoning that task under the weight of time-consuming maintenance.
Try to bundle as much functionality as possible into a single test. That way, if something goes wrong, the errors will propagate anyway. For example, if you have a digest-generating class - test the actual output, not every single helper function.
Don't trust yourself. Assume that you will always make mistakes, and so you write tests to make your life easier, not harder.
If you are not feeling good about writing tests, you are probably doing it wrong ;)
A common practice is to move all the code you can out of the codebehind and into an object you can test in isolation. Such code will usually follow the MVP or MVC design patterns. If you search on "Rhino Igloo" you will probably find the link to its Subversion repository. That code is worth a study, as it demonstrate one of the best MVP implementations on Web Forms that I have seen.
Your codebehind will, when following this pattern, do two things:
Transit all user actions to the presenter.
Render data provided by the presenter.
Unit testing the presenter should be trivial.
Update: Rhino Igloo can be found here: https://svn.sourceforge.net/svnroot/rhino-tools/trunk/rhino-igloo/
There have been tries on getting Microsoft's free UI Automation (included in .NET Framework 3.0) to work with web applications (ASP.NET). A german company called Artiso happens to have written a blog entry that explains how to achieve that (link).
However, their blogpost also links an MSDN Webcasts that explains the UI Automation Framework with winforms and after I had a look at this, I noticed you need the AutomationId to get a reference to the respecting controls. However, in web applications, the controls do not have an AutomationId.
I asked Thomas Schissler (Artiso) about this and he explained that this was a major drawback on InternetExplorer. He referenced an older technology of Microsoft (MSAA) and was hoping himself that IE8 will do this better.
However, I was also giving Watin a try and it seems to work pretty well. I even liked Wax, which allows to implement simple testcases via Microsoft Excel worksheets.
Ivonna can unit test your views. I'd still recommend moving most of the code to other parts. However, some code just belongs there, like references to controls or control event handlers.