Has anyone used BDD for driving their domain Layer?
Yes, we have found this process to have worked very well and used specflow to deliver this approach fairly easy. We have over 2000+ scenarios implemented in our domain layer alone and we have also used this approach for testing our controllers in our UI layer too(another 2000+ tests).
It's a good idea if working on a large project to put some thought into how to organise the steps before you start as you will quickly start to collect a large amount of steps and finding a step can become a bit of a challenge.
The biggest issue we had was having multiple people on a team writing scenarios, they would often write the same step but with a slightly different wording resulting in the same step being added twice.
Yes, although lately we've been looking at Cuke and Specification by Example as a higher level to start driving from. See http://specificationbyexample.com/
Yes, that's what it's for!
I've found BDD main benefits is how it, in a natural way, lets you;
Drive the design (plan then do)
Discover and emphasize the domains ubiquitous language
Document project progress and current state (specs maps to stories and sprint plans)
If it also results in acceptance or unit tests that's great but I think most value comes out of the above. It also helps new team members get a grip on things and it's very easy to return to projects domain mentally after being away for a while.
I also agree on before mentioned "step-duplication" problems, it's well spent time refactoring and consolidating steps trying to keep them well-structured.
Related
I watched some videos, read some blogs about it. SO has many questions and answers on that subject but I can not find anywhere exact answer for my question.
Almost every question and answer has a lack of usage context.
I have one middle sized, asp.net-mvc, monolith application which is running in one process on IIS. I want to (refactor and) go all the way with DDD (and CQRS without separated storage for reads and writes for now) but for me it looks like impossible mission without breaking some rules/guides/etc.
Bounded Context
For example I have more than one BCs. Each should not cross their boundaries which means should not share their storage. Right?
It is not possible if you use the whole known (everywhere scattered over the web) solution to work with NHibernate session and UoW.
Aggregate Root
Only one AR should be modified in one transaction. When others ARs are involved should introduce eventual consistency (if I remember those are Eric Evans words).
I try to do it but it is not easy in app like that. Pub/Sub not working as desired because if event is published then all subscribers are take their action within one transaction (NSB/MT does that way).
If event handlers wants to modify others ARs they should be executed in separated transactions, right?
Is it possible to deal with it in monolith application (application where whole code works in one process)?
It is not possible if you use the whole known (everywhere scattered
over the web) solution
[...]
if event is published then all subscribers are take their action
within one transaction
I think you're setting yourself useless and harmful constraints by trying to stick to some "state of the art".
Migrating an entire application to DDD + CQRS is a massive undertaking. Some areas of it don't have well-documented beaten paths yet and you'll probably have a fair bit of exploration to do. My best advice would be to stay at a reasonable distance from "the way people do things". Both in traditional ASP.Net web apps because mainstream practices often don't match the way DDD+CQRS works, and in CQRS itself because the case studies out there are few and far between and most probably very domain specific, with a tendency to advocate the use of heavy tools which may not make sense in your context.
You may need to think out of the box, adopt things incrementally and refrain from goldplating everything. You'll be better off starting with very simple implementations that suit your needs exactly than throwing a ton of tools and frameworks at your codebase.
For instance, do you really need a service bus or could a simple Observer pattern suffice ?
Regarding NHibernate, most implementations out there use a (single) Session Per Request approach, but just because it's the most popular doesn't mean it's the only one. Have you tried using multiple ISessions (one for each BC) available at a more programmable level, such as per-action, or managed entirely manually ? Conversely, have you considered sharing a database between Bounded Contexts at first and see for yourself if that's bad or not ?
I have a fairly large MVC3 application, of which I have developed a small first phase without writing any unit tests, targeted especially detecting things like regressions caused by refactoring. I know it's a bit irresponsible to say this, but it hasn't really been necessary so far, with very simple CRUD operations, but I would like to move toward a TDD approach going forward.
I have basically completed phase 1, where I have written actions and views where members can register as authors and create course modules. Now I have more complex phases to implement where consumers of the courses and their trainees must register and complete courses, with academic progress tracking, author feedback and financial implications. I feel it would be unwise to proceed without a solid unit testing strategy, and based on past experience I feel TDD would be quite suitable to my future development efforts here.
Are there any known procedures for 'converting' a development effort to TDD, and for introducing unit tests to already written code? I don't need kindergarten level step by step stuff, but general strategic guidance.
BTW, I have included the web-development and MVC tags on this question as I believe these fields of development can significant influence on the unit testing requirements of project artefacts. If you disagree and wish to remove any of them, please be so kind as to leave a comment saying why.
I don't know of any existing procedures, but I can highlight what I usually do.
My approach for an existing system would be to attempt writing tests first to reproduce defects and then modify the code to fix it. I say attempt, because not everything is reproducible in a cost effective manner. For example, trying to write a test to reproduce an issue related to CSS3 transitions on a very specific version of IE may be cool, but not a good use of your time. I usually give myself a deadline to write such tests. The only exception may be features that are highly valued or difficult to manually test (like an API).
For any new features you add, first write the test (as if the class under test is an API), verify the test fails and implement the feature to satisfy the test. Repeat. When you done with the feature, run it through something like PEX. It will often highlight things you never thought of. Be sensible about which issues to fix.
For existing code, I'll use code coverage to help me find features I do not have tests for. I comment out the code, write the test (which fails), uncomment the code, verify test passes and repeat. If needed, I'll refactor the code to simplify testing. PEX can also help.
Pay close attention to pain points, as it highlights areas that should be refactored. For example, if you have a controller that uses ObjectContext/IDbCommand/IDbConnection directly for data access, you may find that you require a database to be configured etc just to test business conditions. That is my hint that I need an interface to a data access layer so I can mock it and simulate those business conditions in my controller. The same goes for registry access and so forth.
But be sensible about what you write tests for. The value of TDD diminishes at some point and it may actually cost more to write those tests than it is to give it to someone in India to manually test.
There is Ruby on Rails (1.8, 2.3.2) project. First version of project was made by some organisation. I will implement next versions of this project without any help from this organisation. I will be able to talk with developers from previous development team during meeting (1-3 hours).
Project statistics: ~10k LOC, 1.0/0.6 code to test ratio, rspec
What questions about project can you recommend to ask?
First review the entire project and to figure out as much as possible so you have context and can actually understand what they tell you.
Ask
If you can record the conversation
For an architectural overview
Why they made certain architectural decisions over another
A complete list of dependencies (if you can't figure that out on your own)
What the biggest problems are
Which parts of the projects are always / never being fixed
What the Achilles' Heel of the project is
What will cause the biggest headaches
What security issues are there and what the constraint is to fixing it
What would you do next if you were me?
What you should know that you didn't ask (most important question)
Also, don't be judgemental, you want them to reveal any problems they know about. There are probably tons of things wrong with the app that they are embarassed about, which you need to know sooner rather than later. They're not going to open up to you if they don't trust you.
I would ask for a code walkthrough. Not line-by-line, but more for the overall structure of the project, relationships between individual modules, etc.
Find out the Why's. How is easy enough to see in the codebase, but the why is sometimes impossible to figure out, and will bite you in the ass.
For instance...
Which parts of the application were the biggest performance issues? Which of those issues were resolved? Which are still issues?
Why did you opt for pattern / tool / library x? What other things did you consider? Why?
This will hopefully. (Hit some wood.) Help keep you from having to trudge through the same learning curve and mistakes that the first team had to deal with, and should give you good insight into where the first team actually made a poor choice, instead of making a choice based on factors you have not accounted for yet.
Ask if the new features will cause any major changes to the existing code (architecturally) and what the implication of that will be with other dependent parts of the application.
Also get their emails, as you will have more questions.
One of the most important things, in my opinion, is to get as much technical documentation as you can prior to meeting with them. You should try to go into the meeting as informed as possible, so that you not only know what areas you need to focus on the most, but also to have a preexisting knowledge of how some of the subsystems relate to each other.
Also, do not be afraid to ask what they would have done differently, if given the chance. Some of the best ideas come too late in the development process to be implemented - be it from library availability, change in requirements, change in team, etc.
Bring cookies (or pizza, beer, or wine as appropriate); you will want them to have positive memories of you for when you call with questions.
Edit: to put my answer in the form of a question: "May I offer you a home-baked cookie?"
Perhaps you have done this already, but I would make sure you can:
Checkout the latest version
Run all the migrations
Run all the tests
Deploy (even if to a staging server)
Run the application locally
Before you go to the meeting, so you can make sure you can by the time it is over.
Other things that might be useful
data model
UI wireframes
bug tracker data / issue tracker data
who are the customers / people representing customers
development environment configuration
source control locations, etc.
explanation of special configuration settings
Wow! All great answers, right down to the cookies.
My contribution assumes that this is your one and only chance to access the old dev team, therefore you need to kick it up a notch:
Agenda. Split the meeting into several parts, for instance:
A quick (15 min) introduction and arch overview
One on one with team members.
Design review as a group, etc.
Positive Energy. Especially if the relationship is inherently difficult, keep a positive focus by postulating: what improvements would you put into the next version - (rewrite is not an option, right Joel) - capture every nuance, and drill down past their comfort level only nearer the end.
Facilitator. Use a trained design meeting facilitator. They can help prep for the meeting, conduct pre-meeting interviews, design the agenda. During the meeting they can drive the intensity, and keep the focus. They can also suggest forms of capturing what can be a fair amount of information.
Also, I would try to id all design artifacts beyond the code, if any, and come to an understanding of how accurate it is. This may include doing design reviews of key elements of these documents vis a vis the as-built system.
Don
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.
In FogBugz 6, how do I represent the concepts of a "feature" versus a "task"? As defined by Joel Spolsky, the owner of Fog Creek Software (which makes FogBugz), a feature is essentially a user-visible capability. To estimate the time to implement a feature, the developer should break the implementation into short tasks (2 days max) to ensure they think about each step.
FogBugz has only cases. I can't tell whether they're supposed to correspond to features or tasks. Some FogBugz documentation indicates that each case is a task, which is fine except there is no way to group all the tasks for a given feature together. This is especially odd given that, before FogBugz 6, Joel advocated using a spreadsheet with that grouped all the tasks for each feature. But his own software doesn't appear to meaningfully support that grouping.
I realize that the Joel article I reference includes a disclaimer pointing to a later article. However, the later article does not settle this issue, in fact it doesn't discuss features versus tasks at all, which is surprising given how well Joel advocates for those concepts in the first article.
For FogBugz 6.0 and earlier:
Make a case for each work item (task). FogBugz calls them "Features," only to distinguish them from bugs, but you do want one case for each task.
The best way to group a bunch of tasks is to make a Release (Fix-For) and assign all of the tasks to that release.
Responding to AviD's comment/question to Joel:
So, if you have 10 new features coming
in the next version, with each feature
needing 5 tasks to implement, you
recommend creating 10 releases? And
how do I define that these are the
features/"releases" that are to be
included in the upcoming release?
Here is how we dealt with this specific problem in our development process:
First, we made a regular release schedule: monthly internal releases and quarterly external releases. This schedule never changes but task assignment / feature completion does. This is hugely important in terms of simplifying our inter-human communication: don't try to argue with the calendar.
Major features ("10 new features" in your example) are turned into cases (e.g., case 101 to case 110).
Each task that is a sub-component of a major feature also gets created as a sub-case with a description of what makes this chunk of work an important part of the larger picture. Previously, in Fogbugz 6, we used the "See also" feature by allowing it to search the text for us ("This is a sub-component of case 101" for example). This was effectively the same thing but less aesthetic.
Now that we've broken down the work to its finest level of usefulness, we bring the actual developers into the discussion. Each task and major feature is individually assigned to a particular developer.
The developer determines when they can get their assigned work done by picking the appropriate internal release date that they think they can commit to.
At this point, we have a rough sketch of what will get done for each release. Further refinements continue as the working people actually estimate the hours that they'll need to do the work, enabling evidence-based scheduling, etc.
For AviD's question, though, he would have the release-assignment problem solved by step 5 above.
However, I think point 6 is the most interesting as that's where you really get a solid schedule. For example, if developers are having trouble estimating a larger task, they break it down into sub-cases even further. Notice how my assessment of "finest level of usefulness" can differ (perhaps greatly) from the person who really needs to get the work done.
This is also a time when a developer can reach out to someone else and say "I can do most of this but it would really help if person X could help me with this little piece Y." This is actually where I get most of my development tasking: I personally sit in multiple places during this process, from large-scale planning meetings to little fiddly tasks that no-one else has time to do.
PS: Making it a personal goal to get this answer rated higher than Joel's.... ;-)
PPS: My original response is now overcome by events since Fogbugz 7 has lovely sub-tasks. Program managers love those reports.
You may have better luck asking your questions in the FogBugz Discussion Forum
We use a combination of projects in order to accomplish your grouping goals. We also commonly setup a project "parking" Wiki where links to development cases, technical documentation, systems requirements, user documentation, external links to resources etc. can all be placed. It provides a good "one-stop-shop" for everything related to that project.
As part of that Wiki, we would then setup two specific projects. One in relation to the large overall goals/outlines similar to what might correspond to your Project Management charts/whatnot. One in relation to the development tasks of each feature as they are broken down into the smaller and more manageable chunks. You can then, as was mentioned use case linking to both reference the "master" cases in the other project as well as reference the project Wiki itself so that you can quickly and easily get back to all of your project related information which is conveniently in one spot.
You can accomplish a pile of different organizational structures using FogBugz, you just have to approach things a little differently sometimes in order to hit each and every situation.
Hope that helps.
haha, that article has a disclaimer, but I understand what you are saying.
We use Fogbugz and the only 'Feature' that I am aware of is under category and I don't think you can associated it with sub-tasks.
You can type in 'Case N' is the feature for this task if you just wanted to reference it in the case text.
That kind of stuff sound like is lies more in the project management domain instead of software used to track bugs.
thats a good question, i have asked that myself, too..
we currently test-drive fogbugz for 45 days in a group of 5 developers, and we currently create a "release" for major features. in fact we do not release it, but multiple releases together when something is ready.
there should definately be some sort of advanced task grouping in fogbugz.