bcsc-core Native Unit Testing

Overview

This skill guides creation of native unit tests for the packages/bcsc-core module, which contains Swift (iOS) and Kotlin (Android) implementations of authentication, PIN management, keychain storage, token services, and device authentication.

The codebase already uses protocol-based dependency injection on iOS and interface/class-based injection on Android, making it straightforward to create mock implementations for isolated unit testing.

Test Infrastructure

iOS — XCTest via SPM

Tests are built with Swift Package Manager using the package manifest at packages/bcsc-core/Package.swift. The key concepts:

• BcscCoreTestable target: A subset of production iOS source files compiled for the simulator (without React Native / CocoaPods dependencies). Only files listed in the sources: array are included.
• BcscCoreTests test target: XCTest files under ios/BcscCoreTests/, compiled with @testable import BcscCoreTestable.
• SPM_BUILD flag: A Swift compiler define set in Package.swift via swiftSettings: [.define("SPM_BUILD")]. The file ios/SPMCompat.swift uses #if SPM_BUILD to provide lightweight stubs (e.g., SecureRandom, Data.arrayOfBytes()) for types from JWE files that aren't included in the SPM target.
• Scheme name: xcodebuild uses BcscCoreTests-Package (SPM auto-appends -Package).

Adding a new iOS source file to the test target

If the code under test references types in a file not yet in Package.swift, add it to the sources: array in the BcscCoreTestable target. If that file depends on types from excluded files (e.g., JWE/crypto), add stubs to SPMCompat.swift behind #if SPM_BUILD.

Adding a new iOS test file

1. Create a new .swift file in ios/BcscCoreTests/.
2. Import frameworks and the testable module:

   import LocalAuthentication  // if testing LAPolicy/biometric types
   import XCTest
   @testable import BcscCoreTestable
   

3. Write XCTestCase subclasses. Follow the naming convention {ClassUnderTest}Tests.
4. Run with yarn test:ios or directly:

   xcodebuild test -scheme BcscCoreTests-Package \
     -destination 'platform=iOS Simulator,name=iPhone 16,OS=latest' \
     -skipPackagePluginValidation
   

Android — JUnit 4 + MockK

Tests live under android/src/test/java/com/bcsccore/ mirroring the main source package structure.

Dependencies (in android/build.gradle)

testImplementation 'junit:junit:4.13.2'
testImplementation 'io.mockk:mockk:1.13.8'
testImplementation 'org.robolectric:robolectric:4.11.1'
testImplementation 'androidx.test:core:1.5.0'

Adding a new Android test file

1. Create a Kotlin file in android/src/test/java/com/bcsccore/{subpackage}/, matching the source package.
2. Write standard JUnit 4 test classes with @Test methods.
3. Use io.mockk.mockk<T>() and every { ... } returns ... for mocking.
4. Run with yarn test:android or directly:

   cd android && ./gradlew test
   

Running all tests

yarn test          # runs test:ios then test:android
yarn test:ios      # iOS only
yarn test:android  # Android only

Mocking Strategy

iOS — Protocol Conformance

The codebase defines protocols for all service boundaries. Create mock classes that conform to the protocol and expose controllable properties:

final class MockPINService: PINServiceProtocol {
    var verifyResult: String?        // control return value
    var setPINResult: String = "mock-hash"
    var deletePINCalled = false      // track side effects

    func verifyPINAndGetHash(issuer _: String, accountID _: String, pin _: String) -> String? {
        return verifyResult
    }

    func setPIN(issuer _: String, accountID _: String, pin _: String, isAutoGenerated _: Bool) throws -> String {
        return setPINResult
    }

    func deletePIN(issuer _: String, accountID _: String) throws {
        deletePINCalled = true
    }
    // ... remaining protocol methods
}

Pattern: Use var resultProperty for controlling return values and var methodCalled = false booleans for verifying side effects.

Available iOS protocols for mocking

Android — MockK

Use MockK's mockk<T>() for mocking classes and interfaces:

val mockPinService = mockk<PinService>()
every { mockPinService.validatePIN(any(), "1234") } returns true
every { mockPinService.hasPIN(any()) } returns true

val account = Account(id = "test", issuer = "https://idsit.gov.bc.ca", clientID = "client")
val result = account.verifyPIN("1234", mockPinService)
assertTrue(result.success)

For data classes (e.g., NativeAccount), test serialization round-trips with Gson directly — no mocking needed.

Test Patterns

Time-dependent tests (eg. PIN penalty logic)

The penalty system locks users out after failed PIN attempts. Both platforms accept an injectable "current time" parameter to make tests deterministic.

iOS: Pass verifyDate: parameter:

let start = Date()
for i in 0..<5 {
    _ = account.verifyPIN("wrong", pinService: mock, verifyDate: start.addingTimeInterval(Double(i)))
}
// Advance past penalty before next batch
let afterPenalty = start.addingTimeInterval(65)

Android: Pass timestamp to verifyPIN and isServingPenalty:

val now = System.currentTimeMillis()
account.verifyPIN("wrong", mockPinService, now)
val penalty = account.isServingPenalty(now)

Important: When testing escalating penalties, you must advance time past each penalty tier before triggering the next. Calling verifyPIN while a penalty is active will return "locked" without incrementing the attempt counter.

Penalty tiers: 5 attempts → 1 min, 10 → 10 min, 15 → 1 hour, 20 → 1 day.

NSCoding / Serialization round-trips

iOS — Use NSKeyedArchiver / NSKeyedUnarchiver:

let data = try NSKeyedArchiver.archivedData(withRootObject: original, requiringSecureCoding: true)
let decoded = try NSKeyedUnarchiver.unarchivedObject(ofClass: Account.self, from: data)
XCTAssertEqual(decoded?.id, original.id)

Android — Use Gson:

val json = gson.toJson(original)
val restored = gson.fromJson(json, NativeAccount::class.java)
assertEquals(original.uuid, restored.uuid)

Test naming conventions

iOS: test{Behavior} in camelCase — e.g., testVerifyPINReturnsSuccessOnCorrectPIN Android: Backtick-quoted descriptive names — e.g., `verifyPIN returns success when PIN is correct`

Helper factories

Android — Create a createAccount() helper with defaults to reduce boilerplate:

private fun createAccount(
    id: String = "test-uuid",
    issuer: String = "https://idsit.gov.bc.ca",
    clientID: String = "test-client-id",
    securityMethod: AccountSecurityMethod = AccountSecurityMethod.PIN_NO_DEVICE_AUTH,
): Account = Account(id = id, issuer = issuer, clientID = clientID, securityMethod = securityMethod)

Checklist for adding tests

• Identify the class/struct to test and which platform(s)
• Check if the source file is already in Package.swift sources: (iOS) — add if missing
• Check if new dependencies need stubs in SPMCompat.swift (iOS)
• Create mock(s) for any protocol/interface dependencies
• Place test file in ios/BcscCoreTests/ or android/src/test/java/com/bcsccore/{subpackage}/
• For time-dependent logic, use injectable timestamps rather than Date() / System.currentTimeMillis()
• Run yarn test and verify all tests pass on both platforms

Source: bcgov/bc-wallet-mobile — distributed by TomeVault.