The Messy App

This is a ruby kata exploring coupling & cohesion in a typical messy app. There are two parts. In task 1 we make a change to an app where little consideration to coupling & cohesion has been given. In task 2 we make the same change in a version of the app where coupling is much lower and cohesion higher.

Introduction

Welcome to the Messy Cooperation Kata. Messy Cooperation is a leading provider of financial services. They recently created a new investment portal where people can buy and sell shares.

So far the following is implemented:

Any user can sign up and become an investor on the platform
Any user having a passcode can sign up and become an admin-user
Users can login and logout
Users can manage their profile
Admin-users can generate passcodes
Admin-users can see a list of all registered users
Admin-users can generate passcodes
Investors can buy shares or stocks
Investors can see they value of their portfolio
Investors can see their outstanding fees
Investors can see news regarding investments
Accountants can see outstanding fees

Task 1

Management has now decided, in order to comply with regulations, that a history of all personal data has to be kept in the system. This means, whenever a user changes its name or address a 'valid_from' date is recorded. In most cases the new name or address then is only shown after that date has passed. Because the users are from all over the world, the date of their address change also influences financial calculations, like the conversion rate to the currency where their reside.

Management has spoken about this requirement with the developers of the system but they said that the system has never been designed for such far reaching changes. They just laughed and walked away.

Your team has now been contracted to sort this mess out. Thankfully the developers left a test suite behind which has already been extended to cover the new requirements. Your task is now to make these new tests pass. To start with it make sure you have switched to the branch messy and run the tests. For more help see the section Getting Started below.

Task 2

In an alternative reality the same new requirements were presented to the developers. But in this reality, they said they are happy to implement it, some said they think it will only affect one particular part of the system and it won't take too long.

Because the developers think that it doesn't affect the core logic your team was now brought in to sort it out. To start with it make sure you have switched to the branch modularized and run the tests. For more help see the section Getting Started below.

Getting Started

Prerequisites

If you use asdf and direnv you can just run direnv allow and you are good to go.

Otherwise please ensure:

You have right ruby installed (as listed in .tool-versions).
You set set the SCHEMA environment variable with export SCHEMA=db/schema.rb or add it to all your rake db:* tasks.

Run:

$ bundle install

$ rake db:create db:migrate

$ rspec