11. Serialized vs Parallel Execution

// Semua test ini berjalan paralel (default)
@Suite("Kalkulasi Paralel")
struct CalculationTests {
    @Test func testAddition() { #expect(1 + 1 == 2) }
    @Test func testSubtraction() { #expect(5 - 3 == 2) }
    @Test func testMultiplication() { #expect(3 * 4 == 12) }
    // Ketiga test bisa berjalan bersamaan
}

// Database test yang share koneksi
@Suite(.serialized)
struct DatabaseIntegrationTests {
    static var db: TestDatabase!

    // Karena serialized, setup/teardown predictable
    @Test func testInsert() async throws {
        try await Self.db.insert(User(name: "Alice"))
        let count = try await Self.db.count(User.self)
        #expect(count == 1)
    }

    @Test func testDelete() async throws {
        // Berjalan setelah testInsert selesai (serialized)
        try await Self.db.deleteAll(User.self)
        let count = try await Self.db.count(User.self)
        #expect(count == 0)
    }
}

// Suite luar paralel, sub-suite tertentu serialized
@Suite("Mixed Execution")
struct MixedExecutionTests {
    // Test-test ini paralel
    @Test func fastTest1() { #expect(true) }
    @Test func fastTest2() { #expect(true) }

    // Ini serialized karena share resource
    @Suite(.serialized, "File System Tests")
    struct FileSystemTests {
        @Test func testCreate() throws { /* ... */ }
        @Test func testRead() throws { /* ... */ }
        @Test func testDelete() throws { /* ... */ }
    }
}