The app's purpose is to have an instrument for real-time monitoring of the profit of user investments portfolio. Just open the app and see the answer!
I used the TDD approach (write the test - write code - refactor). The workspace consists of three projects:
- Investments frameworks (platform-agnostic, runs on macOS and iOS)
- Investments App for iOS (platform-specific, runs on iOS)
- Investments App for watchOS (platform-specific, runs on watchOS) Frameworks know nothing about the app. Apps import frameworks for the desired functionality.
The app propagates the Dependency Injection principe, and the central part is a Composition Root (class UIComposer). I used Combine to create a price loader publisher and to maintain subscriptions between different app states. The Combine is extremely useful since you can replace decorators and adapters with standard predefined operators.
For the UI, I used the SwiftUI framework and the ViewInspector to make tests for SwiftUI views.
I used FinHub API (https://finnhub.io/docs/api/authentication) for retrieving current stock prices and Firebase (with REST API) to store transactions.
As a user of the App
I want to store information about my transactions
So I can see all my transactions in the App
Given the user with stored transactions
When the user enters 'Transactions'
He sees a list of stored transactions
Given the user editing a stored transaction
When he saves it
He sees the transaction in a stored transactions
Given the user removing a stored transaction
When he removes it
He doesn't see the transaction in a stored transactions
Data:
Primary course (happy path)
1. Execute "RetrieveTransactions" command
2. System encodes stored Transactions
3. System uploads transactions to a Remote transactions storage
4. System delivers successful result
Storage retrival error (sad path)
1. System delivers retrival error
Data:
- Transaction (id)
Primary course (happy path)
1. Execute "DeleteTransaction" command with above Data
2. System encodes Transaction to a stored
3. System removes a stored transaction
4. System delivers successful result
Storage removal error (sad path)
1. System delivers removal error
As a user of the App
I want to ba able to add new transactions
So I can store all new transactions in the app
Given the user adding a new transaction
When the user enters 'Quantity' and 'Sum'
The system calculates 'Price'
Given the user adding a new transaction
When the user tap 'Save'
The system checks the correcthness of all fields
Given the user adding a new transaction
When the user tap 'Save' and system validates all the fields
The system does not save transaction unitl all fields are correct
Given the user adding a new transaction
When he saves it
He sees the transaction in a stored transactions
Given the user adding a new transaction
When he cancels it
He doesn't see the transaction in a stored transactions
Data:
- Date
- Type
- Ticket
- Quantity
- Price
- Sum
Primary course (happy path)
1. Execute "SaveTransaction" command with above Data
2. System validates fields
- Ticket - 3 or 4 letters
- Quantity > 0
- Sum > 0
3. System delivers successful result
Storage saving error (sad path)
1. System delivers error for each of velidating fields
As a user of the App
I want to see summary information about my portfolio
So I can simply understand my profit or loss
Given the user with no transactions
When the user opens 'Portfolio'
He sees an empty view
Given the user with stored transactions
When the user enters 'Portflio'
He sees a tickets list with total current cost, profit and detailed data for each ticket
Given the user with stored transactions
When the user saves new transaction and enters 'Portflio'
He sees an updated portfolio
Data:
Primary course (happy path)
1. Retrieve transactions from storage
2. Get current prices fot tickets
3. Calculate portoflio items and portfolio summary
4. System delivers successful result
Storage retrival error (sad path)
1. System delivers retrival error
Current prices retrival error (sad path)
1. System delivers current prices retrieval error
As a user of the App
I want to see current prices of my items
So then I can see total cost of my profile and calc profit
Given the user with internet connection
When the user opens 'Portfolio'
The system loads current prices via the Internet
Given the user without internet connection
When the user opens 'Portfolio'
The system loads current prices from the cache
Data:
- Ticket
Primary course (happy path)
1. Retrieve data from the API
2. Decode retrieved to a CurrentPrice model
3. Save retrieved prices to cache
4. System delivers successful result
API connection error (sad path)
1. System delivers connection error
API invalid data error (sad path)
1. System delivers invalid data error
Data:
- Ticket
Primary course (happy path)
1. Retrieve data from the Cache
2. Decode retrieved to a CurrentPrice model
3. System delivers successful result
Cache retrieval error (sad path)
1. System delivers cache error
As a user of the App
I want to see current cost and profit of my portfolio
So I can simply understand my profit or loss without using my iPhone
Given the user with no transactions
When the user launches the app
He sees an view with zero cost and profit
Given the user with stored transactions
When the user launches the app
He sees a total current cost of his investments and his profit
Data:
Primary course (happy path)
1. Retrieve transactions from remote storage
2. Get current prices fot tickets
3. Calculate portfolio summary
4. System delivers successful result
Remote storage retrival error (sad path)
1. System delivers retrival error
Current prices retrival error (sad path)
1. System delivers current prices retrieval error