Swift Testing Migration & Interoperability Modes

−// SharedTestHelpers.swift — old XCTest-only approach
−import XCTest
+// SharedTestHelpers.swift — works in both XCTest and Swift Testing targets
+import Testing
 
−// Legacy helper using XCTFail with file/line for source attribution
+// Updated helper: replaces XCTFail + file/line with Issue.record + sourceLocation
 func assertAllUnique<T: Hashable>(
     _ values: [T],
−    file: StaticString = #file,
−    line: UInt = #line
+    sourceLocation: SourceLocation = #_sourceLocation
 ) {
     var seen = Set<T>()
     for value in values {
         if seen.contains(value) {
−            XCTFail("Duplicate value found: \(value)", file: file, line: line)
+            Issue.record(
+                "Duplicate value found: \(value)",
+                sourceLocation: sourceLocation
+            )
         }
         seen.insert(value)
     }
 }
 
−// --- XCTest using the shared helper ---
−import XCTest
+// --- Swift Testing test using the shared helper ---
+import Testing
 
−class FruitTests: XCTestCase {
+struct Fruit: Hashable {
+    let name: String
+    let climate: String
+}
 
−    func testAllDeliveredFruitsHaveUniqueNames() {
−        let names = ["Mango", "Apple", "Mango"] // intentional duplicate
−        assertAllUnique(names)
−    }
+@Test("All delivered fruits have unique names")
+func allDeliveredFruitsHaveUniqueNames() {
+    let deliveryBatch: [Fruit] = [
+        Fruit(name: "Mango", climate: "Tropical"),
+        Fruit(name: "Apple", climate: "Temperate"),
+        Fruit(name: "Mango", climate: "Tropical") // intentional duplicate
+    ]
+    // assertAllUnique now reports via Issue.record, so failures are
+    // proper Swift Testing errors under Complete/Strict interop mode.
+    assertAllUnique(deliveryBatch.map(\.name))
+}
 
−    func testFruitClimateIsTropical() throws {
−        // continueAfterFailure = false halts on first failure globally
−        continueAfterFailure = false
−        let fruit = (name: "Lychee", climate: "Tropical")
−        XCTAssertEqual(fruit.climate, "Tropical")
−    }
−
−    func testSkipOnCI() throws {
−        try XCTSkipIf(ProcessInfo.processInfo.environment["CI"] != nil,
−                      "Skipping on CI")
−        // ... test body
−    }
+@Test("Fruit climate is tropical", .enabled(if: Locale.current.region?.identifier == "US"))
+func fruitClimateIsTropical() throws {
+    let fruit = Fruit(name: "Lychee", climate: "Tropical")
+    // #require halts the test on failure — replaces continueAfterFailure = false
+    let climate = try #require(fruit.climate as String?)
+    #expect(climate == "Tropical")
 }