Swift Testing Essentials: A Practical Guide

Learn how to add unit and UI testing targets to a SwiftUI app by using the project editor, selecting Swift testing or XC test, and configuring test bundles.

Explore the starter project and learn to add unit and UI testing in Swift. Understand the app’s structure, including social security number validation and the credit score service for tests.

Demonstrates test-driven development for bank deposits by check or cash, verifying that deposits increase balance, and introduces parameterized tests to cover both deposit types in Swift.

Adopt the arrange, act and assert pattern to structure tests, arranging setup, using a single line for the act, and allowing multiple assertions.

Explore test driven development by verifying transfer deposits incur a 2% fee, calculate the net balance, and update tests as fees may change.

Enable audible cues for test results by configuring Xcode to play sounds on success and failure, using breeze for success and an error tone for failures.

Explore how depositing a negative amount triggers an invalid amount error, and implement tests that expect the error and update the deposit function accordingly.

Explore implementing withdrawal with insufficient balance that incurs a penalty, calculating overdraft amounts, and adding tests to verify balance updates and penalty logic.

Explore how depositing an amount updates the bank account's transaction history and ledger, and learn to unit test deposits, amounts, and transaction types (deposit vs withdrawal) to ensure correctness.

Develop and test an APR service that uses a third-party credit score to determine APR ranges from a valid SSN, and learn to replace calls with a stub or mock.

Implement a credit score protocol and a mock credit score service to replace the real third-party dependency in unit tests, enabling fast, network-independent testing with stubbed responses.

Implement APR calculation validation by ensuring the API throws a no credit score found error for SSNs with no credit score, via unit tests and a mock credit score service.

Learn to write Swift integration tests that verify the API service calls get credit score on the credit score service using mocks, confirmations, and expected counts to avoid false positives.

Learn how to prevent the API service from calling the credit score service for invalid SSN by validating the SSN format, using mocks and confirmations in integration tests.

Explore writing UI and end-to-end tests to verify APR results for a valid SSN using a UI test target and accessibility identifiers, with mocked API services.

Configure a credit score service via a factory that switches between mock and production based on a UI test launch argument, enabling reliable UI tests.

Demonstrates how to implement a UI test that displays an error message when a credit score is not found for a given SSN, including setup, input, and verification steps.

Set up a separate unit test target to validate the credit score service via its QA URL, testing valid and invalid SSNs and a 720 score, without mocks.

Test the logic inside views, including UI validation like SSN checks, and extract UI logic into a testable struct such as product filter state for unit tests.

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