Stock Price Tracker App

This project is a Clean Architecture case study for a real-time stock tracker built with three modules:

• StockPriceTracker: feature, presentation, shared presentation, and websocket API
• StockPriceTrackeriOS: SwiftUI rendering layer
• StockPriceTrackerApp: composition root, app services, and navigation

The app tracks 25 seeded stocks, streams live price updates through a websocket echo server, supports list sorting and detail navigation, and handles connection loss with retry flows on both screens.

Model Specs

Stock

Property	Type	Description
symbol	String	Unique stock ticker used as the primary identity
name	String	Company display name
description	String	Company description shown on the detail screen
price	Double	Latest known stock price
previousPrice	Double	Previous stock price used to compute change
history	[Double]	Sliding window of recent prices for the sparkline

Payload contract

The app connects to:

wss://ws.postman-echo.com/raw

The websocket feed uses JSON arrays of stock price updates:

[
  {
    "symbol": "AAPL",
    "price": 182.50
  },
  {
    "symbol": "MSFT",
    "price": 405.12
  }
]

Postman Echo returns the same frame payload, which the app maps into StockMessageMapper.StockPriceUpdate values before merging into the current stock state.

Module Breakdown

StockPriceTracker

• Domain model for Stock
• Feed abstractions such as StockFeedLoader and StockFeedController
• Stock presentation layer with presenters, view models, sorting, and localization
• Shared presentation layer for loading and error presentation
• Websocket infrastructure boundary with WebSocketStockFeedLoader, URLSessionWebSocketClient, and StockMessageMapper

StockPriceTrackeriOS

• SwiftUI screens for the stock list and detail flows
• UI-specific observable state stores
• Reusable rendering components such as connection, price change, and sparkline views

StockPriceTrackerApp

• Composition root and navigation setup
• App-layer composers and adapters that bridge feature APIs into the SwiftUI state stores

Build Instructions

Requirements

• Clone the repository and check out the develop branch
• Xcode 16+ installed (default path: /Applications/Xcode.app)
• iOS Simulator runtimes installed
• macOS can reach wss://ws.postman-echo.com/raw for end-to-end websocket tests

Quick Start (Xcode)

1. Open StockPriceTrackerApp/StockPriceTrackerApp.xcworkspace
2. Select scheme StockPriceTrackerApp
3. Select an iOS Simulator (for example, iPhone 17 Pro)
4. Run (Cmd + R)

Run Tests (Xcode)

• iOS CI-equivalent suite: scheme CI-iOS (workspace: StockPriceTrackerApp/StockPriceTrackerApp.xcworkspace)
• macOS CI-equivalent suite: scheme CI-macOS (project: StockPriceTracker/StockPriceTracker.xcodeproj)
• WebSocket E2E suite: scheme StockWebSocketAPIEndToEndTests (project: StockPriceTracker/StockPriceTracker.xcodeproj)

Build and Test from CLI

From repo root:

xcodebuild clean build test \
  -workspace StockPriceTrackerApp/StockPriceTrackerApp.xcworkspace \
  -scheme "CI-iOS" \
  CODE_SIGN_IDENTITY="" \
  CODE_SIGNING_REQUIRED=NO \
  -sdk iphonesimulator \
  -destination "platform=iOS Simulator,name=iPhone 17 Pro,OS=latest" \
  ONLY_ACTIVE_ARCH=YES

xcodebuild clean build test \
  -project StockPriceTracker/StockPriceTracker.xcodeproj \
  -scheme "CI-macOS" \
  CODE_SIGN_IDENTITY="" \
  CODE_SIGNING_REQUIRED=NO \
  -sdk macosx \
  -destination "platform=macOS" \
  ONLY_ACTIVE_ARCH=YES

Build App Only (without tests)

xcodebuild build \
  -workspace StockPriceTrackerApp/StockPriceTrackerApp.xcworkspace \
  -scheme "StockPriceTrackerApp" \
  -sdk iphonesimulator \
  -destination "platform=iOS Simulator,name=iPhone 17 Pro,OS=latest"

Run WebSocket End-to-End Tests Only

xcodebuild test \
  -project StockPriceTracker/StockPriceTracker.xcodeproj \
  -scheme "StockWebSocketAPIEndToEndTests" \
  -sdk macosx \
  -destination "platform=macOS"

Testing Strategy

The test suite follows the same general direction as the Essential Feed case study:

• framework unit tests focus on public feature, presentation, shared presentation, localization, and websocket seams
• app integration tests exercise the composed list and detail flows through public composition interfaces
• websocket end-to-end coverage lives in a dedicated target and shared scheme so it does not get mixed into the regular unit suite

Current testing layers include:

• StockPriceTrackerTests
• StockPriceTrackeriOSTests
• StockPriceTrackerAppTests
• StockWebSocketAPIEndToEndTests

Flow Diagram

Architecture Diagram