Application Insights does not support tracking for MySQL dependencies out of the box, so I would like to add it as my project relies heavily on MySQL.EF6.
Per the documentation here: https://azure.microsoft.com/en-us/documentation/articles/app-insights-api-custom-events-metrics/#track-dependency
It is possible to add tracking, however to avoid having to wrap every call I make to my database, I would like to override the MySQL.EF6 Library functions of SaveChanges, SaveChangesAsync, Find, FirstOrDefault, etc.
However I am unsure how to accomplish anymore than the SaveChanges/SaveChangesAsync as they are easily overrideable in my DbContext class.
You can try using EF6 logging - https://msdn.microsoft.com/en-us/data/dn469464.aspx.
TL;DR version:
What's the best way to use the .Net Core IConfiguration framework so values in a single appsettings.json file can be used in multiple projects within the solution? Additionally, I need to be able to access the values without using constructor injection (explanation below).
Long version:
To simply things, lets say we have a solution with 3 projects:
Data: responsible for setting up the ApplicationDbContext, generates migrations
Services: class library with some business logic
WebApi: REST API with a Startup.cs
With this architecture, we have to use a work-around for the "add-migration" issue that remains in Core 1.0.0. Part of this work-around means that we have a ApplicationDbContextFactory class that must have a parameterless constructor (no DI) in order for the migration CLI to use it.
Problem: Right now we have connection strings living in two places;
ApplicationDbContextFactory for the migration work-around
in the WebApi's "appsettings.json" file
Prior to .Net Core, we could use ConfigurationManager to pull connection strings for all solution projects from one web.config file based on the startup project. How do we use this new IConfiguration framework to store connection strings in one place that need to be used all over the solution? Additionally, I can't inject into the ApplicationDbContextFactory class' constructor... so that further complicates things (more-so since they changed how the [FromServices] attribute works).
Side note: I would like to avoid implementing an entire DI middleware just to get attribute injection, since Core includes it's own DI framework. If I can avoid that and still access appsettings.json values, that would be ideal.
If I need to add code let me know, this post was already long enough, so I'll hold off on examples until requested. ;)
I have a question concerning the use of EasyMock in junits. We have configured a framework for junits which uses inmemory derby database and EasyMock to test our service project. We use in memory derby for dao layer completely. The question arises on weather to use EasyMock completely or easymock and derby together in the service layer. Below is the scenario :
//class under test is in user-service project
class ServiceClassUnderTest {
IUserService userService;
IAddressService addressService;
public Address getUsersAddress(String id) {
User user = userService.getUserById(id);
// some logic goes here
Address address = addressService.getAddresdByUser(user);
// some validations goes here
return address;
}
}
The class under test is in user-service project and so is the IUserService interface. While IAddressService interface is in address-service project used as a dependency in user-service project.
Now the problem is in the change of approach suggested by some colleagues.
Approach we used to follow
Prepare test data for userService as its in the same project and mock addressService as its part of a dependency project and we might not have much idea about its behaviour and table structure
Advantage : cleaner approach as we have mimimal code for mocking and test data is in separate sql files
Suggested approach
Mock all services irrespective of its being in the same project or part of a dependency project
Disadvantage : more mocking relevant code then actual test related code, making it difficult to maintain and compromises readability.
The code example given is to only explain the scenario where as in real project we have a lot more complex structure with several service beans in a single class.
Could you please give me your suggestions on which approach is better and why considering the arguments provided by me for both approaches ??
A definitive is hard without have the complete big picture. Assuming you really want unit tests, I usually do this:
Test only the query done to the DB with an actual DB
Mock everything that is used by my tested class.
This "everything" should be no more than 3 or 4 dependencies. Otherwise, I will refactor until I get something that is readable.
Having more test code than production code is normal.
If I end up having trivial code in my tested method, I just don't test it. However, a test can also be used to document. So this is a blurry line.
I've been using cucumber for awhile and I've stumbled upon a problem:
Actual question:
Is there a solution to import the examples from a single file/db using cucumber specifically as examples?
Or alternatively is there a way to define a variable while already in-step to be an example?
Or alternatively again, is there an option to send the examples as variables when I launch the feature file/scenario?
The Problem:
I have a couple of scenarios where I would like to use exactly the same examples, over and over again.
It sounds rather easy, but the examples table is very large (more specifically it contains all the countries in the world and their appropriate continents). Thus repeating it would be very troublesome, especially if the table needs changing (I will need to change all the instances of the table separately)
Complication:
I have a rerun function that knows when a specific example failed and reruns it after the test is done.
Restrictions:
I do not want to edit my rerun file
Related:
I've noticed that there is already an open discussion about importing it from csv here:
Importing CSV as test data in Cucumber?
However that discussion is invalid to me because I have the rerun function that only knows to work only with examples, and the solution suggested there ruins that.
Thank you!
You can use CSV and other external file systems with QAF using different BDD syntax.
If you want to use cucumber steps or cucumber runner, you can use QAF-cucumber and BDD2 (preferred) or Gherkin syntax. QAF-cucumber will enable external test data and other qaf features with cucumber.
Below is the example feature file uses BDD2 syntax can be run using TestNG or Cucumber runner.
Feature: feature uses external data file
#datafie:resources/${env}/testdata.csv
#regression
Scenario: Another scenario exploring different combination using data-provider
Given a "${precondition}"
When an event occurs
Then the outcome should "${be-captured}"
testdata.csv file may look like:
TestcaseId,precondition,be-captured
123461,abc,be captured
123462,xyz,not be captured
You can run using TestNG or Cucumber runner. You can use any of inbuilt data provider or custom as well.
After reading the nice answers in this question, I watched the screencasts by Justin Etheredge. It all seems very nice, with a minimum of setup you get DI right from your code.
Now the question that creeps up to me is: why would you want to use a DI framework that doesn't use configuration files? Isn't that the whole point of using a DI infrastructure so that you can alter the behaviour (the "strategy", so to speak) after building/releasing/whatever the code?
Can anyone give me a good use case that validates using a non-configured DI like Ninject?
I don't think you want a DI-framework without configuration. I think you want a DI-framework with the configuration you need.
I'll take spring as an example. Back in the "old days" we used to put everything in XML files to make everything configurable.
When switching to fully annotated regime you basically define which component roles yor application contains. So a given
service may for instance have one implementation which is for "regular runtime" where there is another implementation that belongs
in the "Stubbed" version of the application. Furthermore, when wiring for integration tests you may be using a third implementation.
When looking at the problem this way you quickly realize that most applications only contain a very limited set of component roles
in the runtime - these are the things that actually cause different versions of a component to be used. And usually a given implementation of a component is always bound to this role; it is really the reason-of-existence of that implementation.
So if you let the "configuration" simply specify which component roles you require, you can get away without much more configuration at all.
Of course, there's always going to be exceptions, but then you just handle the exceptions instead.
I'm on a path with krosenvold, here, only with less text: Within most applications, you have a exactly one implementation per required "service". We simply don't write applications where each object needs 10 or more implementations of each service. So it would make sense to have a simple way say "this is the default implementation, 99% of all objects using this service will be happy with it".
In tests, you usually use a specific mockup, so no need for any config there either (since you do the wiring manually).
This is what convention-over-configuration is all about. Most of the time, the configuration is simply a dump repeating of something that the DI framework should know already :)
In my apps, I use the class object as the key to look up implementations and the "key" happens to be the default implementation. If my DI framework can't find an override in the config, it will just try to instantiate the key. With over 1000 "services", I need four overrides. That would be a lot of useless XML to write.
With dependency injection unit tests become very simple to set up, because you can inject mocks instead of real objects in your object under test. You don't need configuration for that, just create and injects the mocks in the unit test code.
I received this comment on my blog, from Nate Kohari:
Glad you're considering using Ninject!
Ninject takes the stance that the
configuration of your DI framework is
actually part of your application, and
shouldn't be publicly configurable. If
you want certain bindings to be
configurable, you can easily make your
Ninject modules read your app.config.
Having your bindings in code saves you
from the verbosity of XML, and gives
you type-safety, refactorability, and
intellisense.
you don't even need to use a DI framework to apply the dependency injection pattern. you can simply make use of static factory methods for creating your objects, if you don't need configurability apart from recompiling code.
so it all depends on how configurable you want your application to be. if you want it to be configurable/pluggable without code recompilation, you'll want something you can configure via text or xml files.
I'll second the use of DI for testing. I only really consider using DI at the moment for testing, as our application doesn't require any configuration-based flexibility - it's also far too large to consider at the moment.
DI tends to lead to cleaner, more separated design - and that gives advantages all round.
If you want to change the behavior after a release build, then you will need a DI framework that supports external configurations, yes.
But I can think of other scenarios in which this configuration isn't necessary: for example control the injection of the components in your business logic. Or use a DI framework to make unit testing easier.
You should read about PRISM in .NET (it's best practices to do composite applications in .NET). In these best practices each module "Expose" their implementation type inside a shared container. This way each module has clear responsabilities over "who provide the implementation for this interface". I think it will be clear enough when you will understand how PRISM work.
When you use inversion of control you are helping to make your class do as little as possible. Let's say you have some windows service that waits for files and then performs a series of processes on the file. One of the processes is to convert it to ZIP it then Email it.
public class ZipProcessor : IFileProcessor
{
IZipService ZipService;
IEmailService EmailService;
public void Process(string fileName)
{
ZipService.Zip(fileName, Path.ChangeFileExtension(fileName, ".zip"));
EmailService.SendEmailTo(................);
}
}
Why would this class need to actually do the zipping and the emailing when you could have dedicated classes to do this for you? Obviously you wouldn't, but that's only a lead up to my point :-)
In addition to not implementing the Zip and email why should the class know which class implements the service? If you pass interfaces to the constructor of this processor then it never needs to create an instance of a specific class, it is given everything it needs to do the job.
Using a D.I.C. you can configure which classes implement certain interfaces and then just get it to create an instance for you, it will inject the dependencies into the class.
var processor = Container.Resolve<ZipProcessor>();
So now not only have you cleanly separated the class's functionality from shared functionality, but you have also prevented the consumer/provider from having any explicit knowledge of each other. This makes reading code easier to understand because there are less factors to consider at the same time.
Finally, when unit testing you can pass in mocked dependencies. When you test your ZipProcessor your mocked services will merely assert that the class attempted to send an email rather than it really trying to send one.
//Mock the ZIP
var mockZipService = MockRepository.GenerateMock<IZipService>();
mockZipService.Expect(x => x.Zip("Hello.xml", "Hello.zip"));
//Mock the email send
var mockEmailService = MockRepository.GenerateMock<IEmailService>();
mockEmailService.Expect(x => x.SendEmailTo(.................);
//Test the processor
var testSubject = new ZipProcessor(mockZipService, mockEmailService);
testSubject.Process("Hello.xml");
//Assert it used the services in the correct way
mockZipService.VerifyAlLExpectations();
mockEmailService.VerifyAllExceptions();
So in short. You would want to do it to
01: Prevent consumers from knowing explicitly which provider implements the services it needs, which means there's less to understand at once when you read code.
02: Make unit testing easier.
Pete