Some questions about the process of BDD from a beginner

Question

These days I've read several articles about BDD to find what it is talking about. Now I get a basic understandings, but still not clear about the whole process.

The following is what I think to do in a BDD process:

All the stakeholders(BA, customer, Dev, QA) are sitting together to discuss the requirements, and write the agreed features on story cards. Here I take a "user registeration" feature as example:
```
As a user,
I want to register on the system,
so that I can use its services
```

Create several scenarios in Given/When/Then format, and here is one of them:

Scenario: user successfully register
    Given an register page
    And an un-registered user
    When the user fills username "Jeff" and password "123456"
    And click on "Register"
    Then the user can see a "Success" message
    And the user "Jeff" is created in the system

Implement this scenario with some BDD testing framework, say cucumber-jvm, like:

import cucumber.api.java.en.Given;

public class Stepdefs {
    @Given("an register page")
    public void an_register_page throws Throwable {
        // ...
    }
    @Given("an un-registered user")
    public void an_register_page throws Throwable {
        // ...
    }
    // ...
}

for the steps one by one.

But I soon find myself in trouble: there are pages, models, maybe databases need for this scenario, seems a lot of thing to do.

What should I do now?

What should I do now? Do I need to discuss this scenario with all the stakeholders? For BA/Customer/QA, I don't think they really care about the implementations, is it a good idea to discuss it with some other developers?

Suppose after I discuss it with some other developers, we agree to split it to several small parts. Can we make these small parts as "scenario"s with Scenario/Given/When/Then format as what we just did with cucumber-jvm, or can we use JUnit as we normally do in TDD?

1. If choose "cucumber-jvm", it seems a little heavy for small part
2. If choose JUnit, we need to involve more than one testing framework in a project
3. Is it the best if there is a single testing framework to do both things (not sure if there is)

Suppose I choose option 2, using JUnit for the small tasks

The following is what I will do after this decision:

Now we create new small tests to drive implementations, like creating user in database, as we normally do in TDD. (red->green->refactoring). And we don't care the cucumber test Scenario: user successfully register (which is failed) for now, just leave it there. Right?
We develop more small tests with JUnit, made them red -> green -> refactored. (And the imcomplete cucumber test is always failed)
Until all the small tests are passed, we turn to the cucumber test Scenario: user successfully register. Completed it and make sure it turn green at last.
Now develop another scenario, if it's easy, we can implement it just with cucumber, otherwise we will have to split it and write several jUnit test

There are definitely a lot of mis-understandings, even very basic ones. Because I don't find myself gain much value from BDD except the "discuss with all stakeholders" part.

Where is my mistake? Appreciate for any sugguestions!

Lunivore Lunivore · Accepted Answer · 2015-12-01T08:39:33

Don't start with logging in; start with the thing that's different to the other systems out there. Why is someone logging in? Why do they want to use the service? Hard-code a user, pretend they're logged in, focus on the value.
If you focus on UI details you tie yourself to the UI very strongly, and it makes the UI hard to change. Instead, look at what capabilities the system is delivering. I don't recommend using a login scenario anyway, but if I did, I'd expect it to look more like:
```
Given Jeff isn't registered with the site
When he registers with the username "Jeff" and password "123456"  
Then his account creation should be confirmed  
And he should be invited to log in for the first time.
```
Look up "declarative vs. imperative" here to see more on this.
If your UI is really in flux, try out the scenario manually until the UI has settled down a bit. It will be easier to automate then. As you move into more stable scenarios it will be better to automate first (TDD-style).
What should you do now? Well, most people don't write class-level tests for the UI, so don't worry about it until you start driving out the controller and presenter layers. It's normally easier to have frameworks in the same language, but two different frameworks is fine. Cucumber / RSpec, JBehave / JUnit, SpecFlow / NUnit are pretty typical combinations. Do the smallest amount you need to get that first scenario working. It won't be much, because you can hard-code a lot of it. The second scenario will start introducing more interesting behaviour, and then you'll start to see your class-level tests emerge.

BTW, BDD started at a class level, so you can do the same thing with the classes; think of an example of how you might use it, write "Given, When, Then" in comments if your framework doesn't work that way already, and then fill in the gaps!

Yes, your Cucumber scenario will be red throughout, until it isn't.
Ideally you'll be making one last unit test and the Cucumber scenario pass at the same time, rather than just writing a bit of extra code. It's very satisfying to see it finally go green.
The original point of BDD was to get rid of the word "test", since it causes people to think of things like TDD as being about testing. TDD's really about clean design; understanding the responsibilities and behaviour of your code, in the same way that scenarios help you understand the capabilities and behaviour of your system. It should be normal to write both system-level scenarios and class-level tests too.

You're already ahead of all the people who forget to discuss the scenarios before they start coding, though! The conversations with stakeholders are the most important part. You might get value out of including a tester in those conversations. Testers are very good at spotting scenarios that other people miss.

It looks like you're pretty much on the right track where the rest of the process is concerned. You might find some of the other BDD answers in my profile helpful for you too. Congrats and good luck!

Some questions about the process of BDD from a beginner

The following is what I think to do in a BDD process:

What should I do now?

2 Answers