   func testModuleAliasingWithExplicitBuild() throws {
     try withTemporaryDirectory { path in
       try localFileSystem.changeCurrentWorkingDirectory(to: path)
+      let moduleCachePath = path.appending(component: "ModuleCache")
+      try localFileSystem.createDirectory(moduleCachePath)
       let srcBar = path.appending(component: "bar.swift")
       let moduleBarPath = path.appending(component: "Bar.swiftmodule").nativePathString(escaped: true)
       try localFileSystem.writeFileContents(srcBar) {

  func testExplicitModuleBuildEndToEnd() throws {
    try withTemporaryDirectory { path in
      try localFileSystem.changeCurrentWorkingDirectory(to: path)
      let main = path.appending(component: "testExplicitModuleBuildEndToEnd.swift")
      try localFileSystem.writeFileContents(main) {
        $0 <<< "import C;"

                                      "-working-directory",
                                      path.nativePathString(escaped: true),
                                      "-emit-module",
                                      "-emit-module-path", moduleFooPath,
                                      "-module-cache-path", moduleCachePath.nativePathString(escaped: true),
                                      "-module-alias",
                                      "Car=Bar",
                                      srcFoo.nativePathString(escaped: true),
