Agile with Yii 1.1 and PHP5: The TrackStar Application

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(For more resources on Agile, see here.)

Introducing TrackStar

TrackStar is a Software Development Life Cycle (SDLC) issue management application. Its main goal is to help keep track of all the many issues that arise throughout the course of building software applications. It is a user-based application that allows the creation of user accounts and grants access to the application features, once a user has been authenticated and authorized. It allows a user to add and manage projects.

Projects can have users associated with them (typically the team members working on the project) as well as issues. The project issues will be things such as development tasks and application bugs. The issues can be assigned to members of the project and will have a status such as not yet started, started, and finished. This way, the tracking tool can give an accurate depiction of projects with regard to what has been accomplished, what is currently in progress, and what is yet to be started.

Creating user stories

Simple user stories are a great way to identify the required features of your application. User stories, in their simplest form, state what a user can do with a piece of software. They should start simple, and grow in complexity as you dive into more and more of the details around each feature. Our goal here is to begin with just enough complexity to allow us to get started. If needed, we’ll add more detail and complexity later.

We briefly touched on the three main entities that play a large role in this application: users, projects, and issues. These are our primary domain objects, and are extremely important items in this application. So, let’s start with them.

Users

TrackStar is a user-based web application. There will be two high-level user types:

  • Anonymous
  • Authenticated

An anonymous user is any user of the application that has not been authenticated through the login process. Anonymous users will only have access to register for a new account or to log in. All other functionality will be restricted to authenticated users.

An authenticated user is any user that has provided valid authentication credentials through the login process. In other words, authenticated users are logged-in users. They will have access to the main features of the application such as creating and managing projects, and project issues.

Projects

Managing the project is the primary purpose of the TrackStar application. A project represents a general, high-level goal to be achieved by one or more users of the application. The project is typically broken down into more granular tasks (or issues) that represent the smaller steps that need to be taken to achieve the overall goal.

As an example, let’s take what we are going to be doing throughout this book, that is, building a project and issue tracking management application. Unfortunately, we can’t use our yet-to-be-created application as a tool to help us track its own development. However, if we were using a similar tool to help track what we are building, we might create a project called Build The TrackStar Project/Issue Management Tool. This project would be broken down into more granular project issues such as ‘Create the login screen’ or ‘Design database schema for issues’, and so on.

Authenticated users can create new projects. The creator of the project within an account has a special role within that project, called the project owner. Project owners have the ability to edit and delete these projects as well as add new members to the project. Other users associated with the project—besides the project owner—are referred to simply as project members. They have the ability to add new issues, as well as edit existing ones.

Issues

Project issues can be classified into one of the following three categories:

  • Features: Items that represent real features to be added to the application. For example, ‘Implement the login functionality’
  • Tasks: Items that represent work that needs to be done, but is not an actual feature of the software. For example, ‘Set up the build and integration server’
  • Bugs: Items that represent application behaviors that are not working as expected. For example, ‘The account registration form does not validate the format of input e-mail addresses’

Issues can have one of the following three statuses:

  • Not yet started
  • Started
  • Finished

Project members can add new issues to a project, as well as edit and delete them. They can assign issues to themselves or other project members.

For now, this is enough information on these three main entities. We could go into a lot more detail about what exactly account registration entails’ and how exactly one adds a new task to a project’, but we have outlined enough specifications to begin on these basic features. We’ll nail down the more granular details as we proceed with the implementation.

However, before we start, we should jot down some basic navigation and application workflow. This will help everyone to better understand the general layout and flow of the application we are building.

Navigation and page flow

It is always good to outline the main pages within an application, and how they fit together. This will help us quickly identify some needed Yii controllers, actions and views as well as help to set everyone’s expectations as to what we’ll be building towards at the onset of our development.

The following figure shows the basic idea of the application flow from logging in, through the project details listing:

Agile Web Application Development with Yii 1.1 and PHP5

When users first come to the application, they must log in to authenticate themselves before accessing any functionality. Once successfully logged-in, they will be presented with a list of his current projects along with the option to create a new project. Choosing a specific project will take them to the project details page. The project details page will present a list of the issues by type. There will also be the option to add a new issue as well as edit any of the listed issues.

This is all pretty basic functionality, but the figure gives us a little more information on how the application is stitched together and allows us to better identify our needed models, views, and controllers. It also allows something visual to be shared with others so that everyone involved has the same ‘picture’ of what we are working towards. In my experience, almost everyone prefers pictures over written specifications when first thinking through a new application.

Defining a data scheme

We still need to think a little more about the data we will be working with as we begin to build toward these specifications. If we pick out all the main nouns from our system, we may end up with a pretty good list of domain objects and, by extension of using Active Record, the data we want to model. Our previously outlined user stories seem to dictate the following:

  • A User
  • A Project
  • An Issue

Based on this and the other details provided in the user stories and application workflow diagram, a first attempt at the needed data is shown in the following figure.

Agile Web Application Development with Yii 1.1 and PHP5

This is a basic object model that outlines our primary data entities, their respective attributes, and some of the relationships between them. The 1..* on either side of the line between the Project and User objects represents a many-to-many relationship between them. A user can be associated with one or more projects, and a project has one or more users. Similarly we have represented the fact that a project can have zero or more issues associated with it, whereas an issue belongs to just one specific project. Also, a user can be the owner of (or requester of) many issues, but an issue has just one owner (and also just one requester).

We have kept the attributes as simple as possible at this state. A User is going to need a username and a password in order to get past the login screen. The Project has only a name

Issues have the most associated information based on what we currently know about them. As discussed briefly in the user stories above, they will have a type attribute to distinguish the general category (bug, feature, or task). They will also have a status attribute to indicate the progress of the issue being worked on. A user in the system will initially create the issue, this is the requester. Once a user in the system has been assigned to work on the issue, they will be the owner of the issue. We have also defined the description attribute to allow for some descriptive text of the issue to be entered.

Notice that we have not explicitly talked about schemas or databases yet. The fact is, until we think through what is really needed from a data perspective, we won’t know the right tool to use to house this data. Would flat files on the filesystem work just as well as a relational database? Do we need a persistent data at all?

 

The answers to these questions are not needed in this early planning state. It is better to focus more on the features that we want and the type of data needed to support these features. We can turn to the explicit technology implementation details after we have had a chance to discuss these ideas with other project stakeholders to ensure we are on the right track. Other project stakeholders include anyone and everyone involved in this development project. This can include the client, if building an application for someone else, as well as other development team members, product/project managers, and so on. It is always a good idea to get some feedback from “the team” to help validate the approach and any assumptions being made.

However, before we dive right into building our application, we need to cover our development approach. We will be employing some specific development methodologies and principles, and it makes sense to go over these prior to getting started with coding.

Defining our development methodology

We will be employing an agile inspired process of iterative and incremental development as we build this application. ‘Agile’ is certainly a loaded term in modern software development and can have varied meanings among developers. Our process will focus on the aspects of an agile methodology that embrace transparent and open collaboration, constant feedback loops, and a strong ability to respond quickly to changing requirements.

We will work incrementally in that we won’t wait until every detail of the application has been specified before we start coding. Once the details of a particular feature have been finalized, we can begin work on implementing that feature, even though other features or application details are still in the design/planning stage.

The process surrounding this feature implementation will follow an iterative model. We will do some initial iteration planning, engage in analysis and design, write the code to try out these ideas, test the code, and gather feedback. We then repeat this cycle of design->code->test->evaluation, until everyone is happy. Once everyone is happy, we can deploy the application with the new feature, and then start gathering the specifications on the next feature(s) to be implemented in the next iteration.

Automated software testing

Gathering feedback is of fundamental importance to agile development. Feedback from the users of the application and other project stakeholders, feedback from the development team members, and feedback directly from the software itself. Developing software in a manner that will allow it to tell you when something is broken can turn the fear associated with integrating and deploying applications into boredom. The method by which you empower your software with this feedback mechanism is writing unit and functional tests, and then executing them repeatedly and often.

Unit and functional testing

Unit tests are written to provide the developer with verification that the code is doing the right things. Functional tests are written to provide the developer, as well as other project stakeholders, that the application, as a whole, is doing things the right way.

Unit tests

Unit tests are tests that focus on the smallest units within a software application. In an object-oriented application, (such as a Yii web application) the smallest units are the public methods that make up the interfaces to classes. Unit tests should focus on one single class, and not require other classes or objects to run. Their purpose is to validate that a single unit of code is working as expected.

Functional tests

Functional tests focus on testing the end-to-end feature functionality of the application. These tests exist at a higher level than the unit tests and typically do require multiple classes or objects to run. Their purpose is to validate that a given feature of the application is working as expected.

Benefits of testing

There are many benefits to writing unit and functional tests. For one, they are a great way to provide documentation. Unit tests can quickly tell the exact story of why a block of code exists. Similarly, functional tests document what features are implemented within an application. If you stay diligent in writing these tests, then the documentation continues to evolve naturally as the application evolves.

They are also invaluable as a feedback mechanism to constantly reassure the developer and other project stakeholders that the code and application is working as expected. You run your tests every time you make changes to the code and get immediate feedback on whether or not something you altered inadvertently changed the behavior of the system. You then address these issues immediately. This really increases the confidence that developers have in the application’s behavior and translates to fewer bugs and more successful projects.

This immediate feedback also helps to facilitate change and improving the design of the code base. A developer is more likely to make improvements to existing code if a suite of tests are in place to immediately provide feedback as to whether the changes made altered the application behavior. The confidence provided by a suite of unit and functional tests allows developers to write better software, release a more stable application, and ship quality products.

Test-driven development

Test-driven development (TDD) is a software development methodology that helps to create an environment of comfort and confidence by ensuring your test suite grows organically with your application, and is always up-to-date. It does this by stipulating that you begin your coding by first writing a test for the code you are about to write. The following steps sum up the process:

  1. Begin by writing a test that will quickly fail.
  2. Run the test to ensure it does, indeed, fail.
  3. Quickly add just enough code to the class you are testing to get the test to pass.
  4. Run the test again to ensure it does, indeed, pass.
  5. Refactor the code to remove any repetitive logic or improve any corners cut while you were just trying to get the test to pass.

These steps are then repeated throughout the entire development process.

Even with the best intentions, if you wait to write your tests until after the code is completed, you probably won’t. Writing your tests first and injecting the test writing process directly into the coding process will ensure the best test coverage. This depth of coverage will help minimize the stress and fear that can accompany complex software applications and build confidence by constantly providing positive feedback as additions and changes are made.

In order to embrace a TDD process, we need to understand how to test within a Yii application.

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