Building a testable MVC3 & EF 4.1 app [closed] - asp.net-mvc

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First, I apologize for the open-ended nature of this question. However, I've been paralyzed by this for months, and in spite of consent searching, still cannot get past this.
I have been working on an MVC/EF app for a while. I'm trying to get an understanding on how to design and build a testable MVC3 application backed by Entity Framework (4.1). You can see a few questions I've asked on the subject here, here, and here.
I'm trying not to over complicate it, but I want it to be a sound, loosely coupled design that can grow. The way I understand it, the following are pretty much bare minimum required components:
MVC app
This is very thin. As little logic as possible goes here. My views have as little conditional logic as possible, my view models are never more than POCOs, and my controllers simply handle the mapping between the view models and domain models, and calling out to services.
Service layer + interfaces (separate assemblies)
This is where all of my business logic goes. The goal of this is to be able to slap any thin client (forms app, mobile app, web service) on top of this to expose the guts of my application. Interfaces for the service layer sits in another assembly.
Core utilities/cross-cutting + interfaces (separate assemblies)
This is stuff I build that is not specific to my application, but is not part of the framework or any third party plugin I'm using. Again, interfaces to these components sit in their own assembly.
Repository (EF context)
This is the interface between my domain models and my database. My service layer uses this to retrieve/modify my database via the domain models.
Domain models (EF POCOs)
The EF4 generated POCOs. Some of these may be extended for convenience to other nested properties or computed properties (such as Order.Total = Order.Details.Sum(d => d.Price))
IoC container
This is what is used for injecting my concrete/fake dependencies (services/utilities) into the MVC app & services. Constructor injection is used exclusively throughout.
Here is where I'm struggling:
1) When integration testing is appropriate vs. unit testing. For example, will some assemblies require a mix of both, or is integration testing mainly for the MVC app and unit testing for my services & utilities?
2) Do I bother writing tests against the repository/domain model code? Of course in the case of POCOs, this is not applicable. But what about when I extend my POCOs w/ computed properties?
3) The proper pattern to use for repositories. I know this is very subjective, as every time I see this discussed, it seems everyone has a different approach. Therefore it makes it hard to figure out which way to go. For example, do I roll my own repositories, or just use EF (DbContext) directly?
4) When I write tests for my services, do I mock my repositories, or do I use SQL Lite to build a mock database and test against that? (See debates here and here).
5) Is this an all-or-nothing affair, as in, if I do any testing at all, I should test everything? Or, is it a matter of any testing is better than no testing? If the latter, where are the more important areas to hit first (I'm thinking service layer)?
6) Are there any good books, articles, or sample apps that would help answer most of these questions for me?
I think that's enough for now. If this ends up being too open ended, let me know and I will gladly close. But again, I've already spent months trying to figure this out on my own with no luck.

This is really complex question. Each of your point is large enough to be a separate question so I will write only short summary:
Integration testing and unit testing don't replace each other. You always needs both if you want to have well tested application. Unit test is for testing logic in isolation (usually with help of mocks, stubs, fakes, etc.) whereas integration test is for testing that your components work correctly together (= no mocks, stubs or fakes). When to use integration test and when to use unit test really depends on the code you are testing and on the development approach you are following (for example TDD).
If your POCOs contains any logic you should write unit tests for them. Logic in your repositories is usually heavily dependent on database so mocking context and test them without database is usually useless so you should cover them with integration tests.
It is really dependent on what you expect from repositories. If it is only stupid DbContext / DbSet wrapper then the value of repository is zero and it will most probably not make your code unit testable as described in some referenced debates. If it wraps queries (no LINQ-to-entites in upper layer), expose access to aggregate roots then the meaning of repository is correct separation of data access and exposing mockable interface.
It is fully dependent on previous point. If you expose IQueryable or methods accepting Expression<Func<>> passed to IQueryable internally you cannot correctly mock the repository (well you can but you still need to pair each unit test with integration test testing the same logic). LINQ-to-entities is "side effect" / leaky abstraction. If you completely wrap the queries inside repository and use your own declarative query language (specification pattern) you can mock them.
Any testing is better then no testing. Many methodologies expects high density coverage. TDD goes even to 100% test coverage because test is written always first and there is no logic without test. It is about the methodology you are following and up to your professional decision to chose if you need a test for piece of code.
I don't think that there is any "read this and you will know how to do that". This is software engineering and software engineering is an art. There is no blue print which works in every case (neither in most cases).

Related

Which layer should DBContext, Repository, and UnitOfWork be in? [closed]

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I want to use Layered Architecture and EF, Repository and UoW Pattern in the project.
Which layer should DBContext, Repository, and UnitOfWork be in?
DAL or BLL?
I would put your DbContext implementation in your DAL (Data Access Layer). You will probably get different opinions on this, but I would not implement the repository or unit of work patterns. Technically, the DBContext is the unit of work and the IDbSet is a repository. By implementing your own, you are adding an abstraction on top of an abstraction.
More on this here and here.
DAL is an acronym for Data Access Layer. DbContext, repositories and Unit Of Work are related to working with data so you should definitely place them in DAL.
"Should" is probably not the correct word here, as there are many views on this subject.
If you want to implement these patterns out of the book, I would check out this link from the ASP.NET guys:
https://www.asp.net/mvc/overview/older-versions/getting-started-with-ef-5-using-mvc-4/implementing-the-repository-and-unit-of-work-patterns-in-an-asp-net-mvc-application
But I actually have started to layer it like this:
Controller / Logic <- Where business logic and boundary objects are created and transformed.
Repository <- Where logic related to persistence and transforming entities and query objects
Store <- Where the actual implementations of storage mechanisms reside. This is abstracted away behind an interface.
This way leverages the fact that both the business logic and repository logic are testable, decoupled and free to use whatever mechanism for persistence - or lack thereof. Without the rest of the application knowing anything about it.
This is offcourse true with other patterns as well, this is just my take on this.
DbContext should never cross beyond the boundary of the DAL, if you want to put your repositories or units of work there, you are free to, just do not let them leak their details or dependencies upwards. The DbContext should in my opinion be scoped to as narrow scopes as possible, to keep it as clean as possible - you never know where that context has been... please wear protection! But jokes aside, if you have a async, multithreaded, multinode, big application, using these DbContexts everywhere passing them around, you will get into general concurrency and data race issues.
What I like to do is start with a InMemory store, that I inject into my controller. As soon as that store starts serving multiple entities, and the persistence logic get's more and more complex - I refactor it into a store with a repository on top. Once all my tests pass and I get it working like I want, I start to create database or file system based implementations of that store.
Again my opinions here, because this is a pretty general question, which has few "true" answers, just a lot of opinions.
Most opinions on this are valid, they just have different strengths and weaknesses, and the important part is to figure out which strengths you need, and how you will work with the weaknesses.
Your repository should have a reference to DbSet<T> objects, and once you add, update or remove, from one or more repositories, you should invoke SaveChanges from the UnitOfWork. Therefore you should place DbContext into Unit of Work implementation.

Which data layer / handling architecture or pattern to choose for a non-enterprise web application? (MVC / EF) [closed]

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I need some help in making a design choice for my application. It’s a fairly straightforward web application, definitely not enterprise class or enterprise-anything.
The architecture is standard MVC 5 / EF 6 / C# ASP.NET, and the pages talk to a back-end database that’s in SQL server, and all the tables have corresponding entity objects generated from VS 2013 using the EF designer and I don’t see that changing anytime in the near future. Therefore creating super abstract “what if my database changes” etc. separations is possibly pointless. I am a one-man operation so we're not talking huge teams etc.
What I want is a clean way to do CRUD and query operations on my database, using DbContext and LINQ operations – but I’m not good with database related code design. Here are my approaches
1. Static class with methods - Should I create a static class (my DAL) that holds my datacontext and then provide functions that controllers can call directly
e.g. MyStaticDBLib.GetCustomerById(id)
but this poses problems when we try to update records from disconnected instances (i.e. I create an object that from a JSON response and need to ‘update’ my table). The good thing is I can centralize my operations in a Lib or DAL file. This is also quickly getting complicated and messy, because I can’t create methods for every scenario so I end up with bits of LINQ code in my controllers, and bits handled by these LIB methods
2. Class with context, held in a singleton, and called from controller
MyContext _cx = MyStaticDBLib.GetMyContext(“sessionKey”);
var xx = cx.MyTable.Find(id) ; //and other LINQ operations
This feels a bit messy as my data query code is in my controllers now but at least I have clean context for each session. The other thinking here is LINQ-to-SQL already abstracts the data layer to some extent as long as the entities remain the same (the actual store can change), so why not just do this?
3. Use a generic repository and unitofwork pattern – now we’re getting fancy. I’ve read a bit about this pattern, and there’s so many different advises, including some strongly suggesting that EF6 already builds the repository into its context therefore this is overkill etc. It does feel overkill but need someone here to tell me that given my context
4. Something else? Some other clean way of handling basic database/CRUD
Right now I have the library type approach (1. above) and it's getting increasingly messy. I've read many articles and I'm struggling as there's so many different approaches, but I hope the context I've given can elicit a few responses as to what approach may suit me. I need to keep it simple, and I'm a one-man-operation for the near future.
Absolutely not #1. The context is not thread safe and you certainly wouldn't want it as a static var in a static class. You're just asking for your application to explode.
Option 2 is workable as long as you ensure that your singleton is thread-safe. In other words, it'd be a singleton per-thread, not for the entire application. Otherwise, the same problems with #1 apply.
Option 3 is typical but short-sighted. The repository/unit of work patterns are pretty much replaced by having an ORM. Wrapping Entity Framework in another layer like this only removes many of the benefits of working with Entity Framework while simultaneously increasing the friction involved in developing your application. In other words, it's a lose-lose and completely unnecessary.
So, I'll go with #4. If the app is simple enough, just use your context directly. Employ a DI container to inject your context into the controller and make it request-scoped (new context per request). If the application gets more complicated or you just really, really don't care for having a dependency on Entity Framework, then apply a service pattern, where you expose endpoints for specific datasets your application needs. Inject your context into the service class(es) and then inject your service(s) into your controllers. Hint: your service endpoints should return fully-formed data that has been completely queried from the database (i.e. return lists and similar enumerables, not queryables).
While Chris's answer is a valid approach, another option is to use a very simple concrete repository/service façade. This is where you put all your data access code behind an interface layer, like IUserRepository.GetUsers(), and then in this code you have all your Entity Framework code.
The value here is separation of concerns, added testability (although EF6+ now allows mocking directly, so that's less of an issue) and more importantly, should you decide someday to change your database code, it's all in one place... Without a huge amount of overhead.
It's also a breeze to inject via dependency injection.

Unit Test in MVC [closed]

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I've used mvc5 and Entity Framework 6 in my project. I decided to use MSTest in my project, but I have several questions.
For example I have a class that i called Employee, this class has several dependency to other classes in project for instance company,organization,user.
If i want create test method for an action in Employee controller that return an Employee regard to current user, company and organization in test method I have to create object for employee, user, company and organization then I'll can test this action.
If I want create all objects for test, I have to create a lot of object in each test method this task is very time consumer also I have more complicated object with more dependency to the other object in my project.
I had research in this case, some people recommended to create a database with specific data in it for test purpose, but I know one of the principle in unit test that is that have not been used a database and all test should be able run in memory.
If I want mock up all class is time consumer and possibility of error is high.
What is the best approach to test in this situation ?
Is a unit testing a good choice?
In the web most example is about write unit test for example phone number format or ... somethings like that where can I find proper sample ?
I think you are confusing unit testing your controller with your repository classes.
If you want to do unit testing to your controllers, first you must make its dependencies to services "loosely coupled" using Dependency Injection.
Now, to load all Employee associated objects is a responsibility of the repository service, not the controller. So you must not test that in your controller tests.
You must mock the repository service with a fake repository that returns an object with just the properties your controller need to do work.
Then, in your controllers test, you must check that it does with this data what it has to do.
Of course, you can have multiple test to the same action testing different behavior for different types of data received.
See "Iteration #4 – Make the application loosely coupled" for an
explanation with examples on how to use dependency injection with
controllers.
See "Iteration #5 – Create unit tests", for how to unit test
your controllers. Also here you will find some tools to mock
session and request data to unit test your controllers.
Testing the repository is a completely different task. This is more difficult because to really test it you need a real database.
It depends on your situation, but what I use is a "Test database" that is cleaned and filled with some basic data (or regenerated if the schema has changed) each time some tests are started.
By the way, repository services only responsibility is to load classes from a database, so they don't need dependencies to other services and their tests never will use mocking.
By your question details I can say that not only unit testing should be involved, but actually the entire testing process must be set. My answer will be too broad, so I'll try to boil it down to these couple of suggestions:
in order to gain proper testing activities, you need Test environments (at least one)
unit testing is just one of the (test) levels that must be performed. As you know Unit testing is all about the smallest testable part of an application and nothing more. If you need to cover complex objects creation, usage etc., maybe you need to consider another test level. For example Integration Testing will help you with combined parts of your application and to determine if they function correctly together.
About the part with
mock up all class
In many cases is inevitable to use such approach and even can improve performance. By proper combination of yours
class has several dependency to other classes
For example I use such mocked Test object and cached it, so it can be reused in other test executions. Here very useful is the Flyweight-design-pattern.
An year ago I had to work on such project (ASP .Net, Entity framework etc.) and as an answer to
What is the best approach to test in this situation ?
To establish a serious Test process, that will help you with the reliability of your software.

Structuring an MVC Application wityh Entity Framework and building using TDD

Background
I am about to start the process of creating a new application with MVC 5 and EF6 and building it out with TDD. This is my first MVC application so i have decided to use it as a bit of a learning platform to better understand a whole range of patterns and methodologies that i have been exposed to but have only used in passing up until this point.
I started with this in my head:
EF - Model
Repositories
Services
UI (controllers views)
Removing the Repositories
I shifted this thinking to remove one layer, repositories simply as my understanding has grown i can see the EF (specifically IDbSet) implements a repository pattern or sorts and the context itself is a unit of work, so wrapping it around a further abstraction, for this application at least seems pointless, at that level anyway.
EF will be abstracted at the Service Layer
Removing the Repo's doesn't mean EF will be directly exposed to the controllers as in most cases i will use the services to expose certain methods and business logic to the controllers, but not exclusively exclude EF as i can use it outside of services to do things like building specific queries which could be used at a service level and a controller level, the service layer will simply be a simpler way of mapping specifics from the controller to the EF and data concerns.
This is where it gets a bit ropey for me
Service Layer
My services feel a little bit like repositories in the way they will map certain functions (getById etc), which i am not sure is just naturally the way they are or if my understanding of them is way off and there is more information that i can't find to better my knowledge.
TDD & EF
I have read a ton of stuff about the EF and how you can go about testing with unit wise, how you shouldn't bother as the leakyness of IQueryable and the fact that Linq-to-entities and Linq-to-objects means that you won't get the results that you intend all of the time, but this has led to simply confusing the hell out of me to the point where i have an empty test file and my head is completely blank because i am now over thinking the process.
Update on TDD the reason the TDD tag was included as i thought maybe someone would have an idea on how they approach something like this without a repository because that is an abstraction for abstractions sake. Would they not unit test against it and use other tests to test the query-able behavior like a integration test or end to end test? but from my limited understanding that wouldn't be TDD as the tests would not be driving my design in this instance?
Finally, To The Point
Is the:
EF
Service
UI
architecture a good way to go, initially at least?
Are there any good examples of a well defined service layer out there so i can learn, and are they in the main a way to map certain business operations that have data connotations to some for of persistence mechanic (in this case an ORM and EF) without having the persistence requirements of say a repository?
With the TDD stuff, is it ok to forgo unit tests for service methods that are basically just calling EF and returning data and just opting for slower integration tests (probably in a seperate project so they are not part of the main test flow and can be run on a more ad-hoc basis?
Having one of those weeks and my head feels like it is about to explode.
Lol I've had one of those weeks myself for sure. ;)
I've had the same kind of internal discussions over how to structure MVC projects, and my conclusion is find what's most comfortable to you.
What I usually do is create the following projects:
Core/Domain - here I have my entities/domain model, and any
other thing that may be shared among layers: interfaces, for
example, configuration, settings, and so on.
Data/EF - here
I have all my EF-dependent code: DataContext and Mappings
(EntityTypeConfiguration). Ideally I could create another
version of this using, say NHibernate and MySQL, and the rest of the
solution will stay the same.
Service - this depends on Core
and Data. I agree in the beginning it will look like a simple facade
to your Data, but as soon as you start adding features, you'll find
this is the place to add your "servicemodels". I'm not saying
ViewModel as this is quite Web-ui related. What i mean with
"ServiceModel" is creating a simpler version of your domain objects.
Real example: hide your CreatedOn, CreatedBy properties, for
example. Also, whenever one of your controller's actions grow to
anything over quite simplistic, you should refactor and move that
logic to the service and return to the controller what you really
need.
Web/UI This will be your webApp. It will depend on Core and Service.
You didn't mention dependency injection but you have to definitely look at it.
For testing, you can test your Data using a SqlCompact provider that re-creates the database for each test instead of using a full SqlExpress. This means your DataContext should accept a connectionString parameter. ;)
I've learned a lot seeing big projects source code, like http://www.nopcommerce.com. You could also have a look at http://sharparchitecture.net/ although I bet you already saw that.
Be prepared to have some nightmares with complex object graphs in EntityFramework. ;)
My final advice is: find something specific to do and dive in. Too much abstraction will keep you from starting, and starting is key to practice and understanding.

Why Fit/FitNesse?

What's the point of using Fit/FitNesse instead of xUnit-style integration tests? It has really strange and very unclear syntax in my opinion.
Is it really only to make product owners write tests? They won't! It's too complicated for them. So why should anyone Fit/FitNesse?
Update So it's totally suitable for business-rules tests only?
The whole point is to work with non-programmers, often even completely non-technical people like prospect users of a business application, on what application should do and then put it into tests. While making tests work is certainly too complicated for them, they should be able to discuss tables of sample data filled out in e.g. Word. And the great thing is, unlike traditional specification, those documents live with your application because automated tests force you to update them.
See Introduction To Fit and Fit Workflow by James Shore and follow links to the rest of documentation if you want.
Update: Depends on what you mean by business rules? ;-) Some people would understand it very narrowly (like in business rules engines etc), others---very broadly.
As I see it, Fit is a tool that allows you to write down business (as in domain) use cases with rich realistic examples in a document, which the end users or domain experts (in some domains) can understand, verify and discuss. At the same time these examples are in machine readable form so they can be used to drive automated testing, You neither write the document entirely by yourself, nor requre them to do it. Instead it's a product of callaboration and discussion that reflects growing understanding of what application is going to do, on both sides. Examples get richer as you progress and more corner cases are resolved.
What application will do, not how, is important. It's a form of functional spec. As such it's rather broad and not really organized by modules but rather usage scenarios.
The tests that come out of examples will test external behavior of application in aspects important from business point of view. Yes, you might call it business rules. But lets look at Diego Jancic's example of credit scoring, just with a little twist. What if part of fit document is 1) listing attributes and their scores and then 2) providing client data and checking results, Then which are the actual business rules: scoring table (attributes and their scores) or application logic computing the score for each client (based on scoring table)? And which are tested?
Fit/FitNesse tests seem more suitable for acceptance testing. Other tests (when you don't care about cooperation with clients, users, domain experts, etc., you just want to automate testing) probably will be easier to write and maintain in more traditional ways. xUnit is nice for unit testing and api tests. Each web framework should have some tool for web app/service testing integrated in its modify-build-test-deploy cycle, eg. django has its little test client. You've lots to chose from.
And you always can write your own tool (or preferably tweak some existing) to better fit (pun intended) some testing in your particular domain of interest.
One more general thought. It's often (not always!!!) better to encode your tests, "business rules" and just about anything, in some form of well defined data that is interpreted by some simple, generic piece of code. Then it's easy to use the data in some other way: generate documentation, migrate to new testing framework, port application to new environment/programming language, use to check conformance with some external rules or other system (just use your imagination). It's much harder to pull such information out from code, eg. simple hardcoded unit tests or business rules.
Fit stores test cases as data. In very specific format because of how it's intended to be used, but still. Your domain specific tests may use different formats like simple CSV, JSON or YAML.
The idea is that you (the programmer) defines an easy to understand format, such as an excel sheet. Then, the product owner enters information that is hard to understand for people that is not in the business... and you just validate that your code works as the PO expects running Fit.
The way used in xUnit, can be used for programmers as an input for easy to understand or simple information.
If you're going to need to enter a lot of weird examples with multiple fields in your xUnit test, it will became hard to read.
Imagine a case where you have to decide whether to give a loan to a customer, based on the Age, Married/Single, Amount of Childrens, Wage, Activity, ...
As a programmer, you cannot write that information; and a risk manager cannot write a xUnit test.
Helps reduce redundancy in regression and bug testing. Build manageable repository of test cases. Its like build once and use for ever.
It is very useful during cooperation of the QA and devs teams: QA could show to developer the result of the failed test and a developer will easyly help to solve an environment issue and will understand steps for reproducing a bug.
It is suitable for UI and even for API testing.

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