 }
 
 CStringTests.test("String.decodeCString.with.inout.conversion") {
+  guard #available(SwiftStdlib 5.7, *) else { return }
   var c = Unicode.UTF8.CodeUnit.zero
   var result = String.decodeCString(
     &c, as: Unicode.UTF8.self, repairingInvalidCodeUnits: true

}

CStringTests.test("String.validatingUTF8.with.String.input") {
  let (u8p, dealloc) = getASCIIUTF8()
  defer { dealloc() }
  var str = String(validatingUTF8: "ab")

}

CStringTests.test("String.validatingUTF8.with.inout.conversion") {
  guard #available(SwiftStdlib 5.7, *) else { return }
  var c = CChar.zero
  var str = String(validatingUTF8: &c)
  expectNotNil(str)
