     }
 
     func testMultithreadingDiagnostics() throws {
-
-      try assertDriverDiagnostics(args: "swift", "-num-threads", "-1") {
-        $1.expect(.error("invalid value '-1' in '-num-threads'"))
-      }
-
-      try assertDriverDiagnostics(args: "swiftc", "-enable-batch-mode", "-num-threads", "4") {
-        $1.expect(.warning("ignoring -num-threads argument; cannot multithread batch mode"))
-      }
-
       try assertDriverDiagnostics(args: "swiftc", "-j", "0") {
         $1.expect(.error("invalid value '0' in '-j'"))
       }

    }
  }

  func testScanDependenciesOption() throws {
    do {
      var driver = try Driver(args: ["swiftc", "-scan-dependencies", "foo.swift"])

  }

    func testMultithreading() throws {
      XCTAssertNil(try Driver(args: ["swiftc"]).numParallelJobs)

      XCTAssertEqual(try Driver(args: ["swiftc", "-j", "4"]).numParallelJobs, 4)
