A note forward

To say that this exercise has been over-engineered, would probably be the understatement of the year :). It has been purposely done so in order to show the recruiter proof of experience and competence.

Most of the infrastructure code has been brought in from previous projects, but was developed 100% by myself. There was just no sense in re-implementing all the cross cutting concerns such as logging, correlation, start-up task, etc. Of course there are many ways to do it, project requirements matter a lot.

Sample unit-tests can be found in the following classes: DonationControllerTests, DonationHandlerTests, DonationRequestValidatorTests.

In appSettings.json you will find the following settings:

"Donation": {
    "MinDonationAmount": 2,
    "MaxDonationAmount": 1000000,
    "Taxes": [
        {
            "Name": "Default",
            "TaxType": "GiftAid",
            "ProcessorType": "SimplePercent",
            "ProcessorOptions": {
                "TaxRate": 20
            },
            "FromDate": "2010-01-01 00:00",
            "ToDate": "2019-11-01 00:00"
        },
        {
            "Name": "AfterBrexit",
            "TaxType": "GiftAid",
            "ProcessorType": "SimplePercent",
            "ProcessorOptions": {
                "TaxRate": 25
            },
            "FromDate": "2019-11-01 00:00"
        }
    ]
}

You have the ability to define tax configurations and tax processors. Tax configurations are applied based on TaxType and date. For example, if the UK decides to leave EU, the tax rate may increase. You can provision these tax configuration in advanced so there is no need of a re-deployment. These would probably go into a database.

How to build

API

The api uses .Net Core 2.2. To build and run execute the following commands:

cd api
dotnet build
dotnet run --project JG.FinTechTest\JG.FinTechTest.Api.csproj

You can browse the swagger api specification here: https://localhost:5001/swagger. This is generated automatically using swashbuckle.

UI

The front-end has been built using angular 8, you need to have node.js v10.9 or greater. To build and run execute the following commands:

cd ui
npm install
ng serve

How it looks

JustGiving FinTech Test

A big part of what we do at JustGiving is reclaim the Gift Aid on donations made to charities. This saves them a lot of time and processing overheads.

The calculation for gift aid is [Donation Amount] * ( [TaxRate] / (100 - [TaxRate]) ).

• For unit testing we use NUnit and NSubstitute, these are already referenced in the projects, but feel free to use which ever framework you prefer.
• All stories should be completed with an appropriate amount of testing.
• Please create a public repo (GitHub, BitBucket, GitLab etc) and send us the link, make sure to commit regularly so we can see how you came up with the solution.
• Remember to be RESTful.

Story 1 - Gift Aid Calculator

• Create a calculator.
• Gift aid calculated at a tax rate of 20%.

Story 2 - Endpoint

• Create an endpoint so that other services can access the calculation for Gift Aid.
• Use this swagger spec as the basis for your API

swagger: '2.0'
info:
  title: Gift Aid Service
  version: 1.0.0
basePath: /api
schemes:
  - https
paths:
  /giftaid:
    get:
      summary: Get the amount of gift aid reclaimable for donation amount
      parameters:
        - in: query
          name: amount
          type: number
          required: true
      produces:
        - application/json
      responses:
        '200':
          description: OK
          schema:
            $ref: '#/definitions/GiftAidResponse'
definitions:
  GiftAidResponse:
    type: object
    required:
      - donationAmount
      - giftAidAmount
    properties:
      donationAmount:
        type: number
      giftAidAmount: 
        type: number

Story 3 - Validation

• There are two validation rules:
  • Minimum donation amount is £2.00.
  • Maximum donation amount is £100,000.00.
• Add validation for these cases and any other validation / error handling you think is appropriate for this endpoint.
• Add appropriate tests and document the endpoint

Story 4 - Storing Gift Aid Declarations

• When a user makes a donation with Gift Aid, we need to store information about the donor.
• We need to store:
  • Name
  • Post Code
  • Donation Amount
• Add an endpoint for this.
• Mock a database or add a simple in-memory database (maybe LiteDB) to persist this data.
• Produce a unique id for the declaration.
• Return the declaration id and the gift aid amount in the reponse.
• Add appropriate tests and document the endpoint

Thanks for your time, we look forward to hearing from you!