message: Test creation of .cargo/registry/CACHEDIR.TAG
diff: @@ -93,6 +93,8 @@ fn simple(cargo: fn(&Project, &str) -> Execs) {
  cargo(&p, "clean").run();
  + assert!(paths::home().join(".cargo/registry/CACHEDIR.TAG").is_file());
  +
  // Don't download a second time
  cargo(&p, "build")
  .with_stderr(
  @@ -150,6 +152,8 @@ fn deps(cargo: fn(&Project, &str) -> Execs) {
  ",
  )
  .run();
  +
  + assert!(paths::home().join(".cargo/registry/CACHEDIR.TAG").is_file());
  }
  #[cargo_test]
  @@ -1231,6 +1235,7 @@ fn updating_a_dep(cargo: fn(&Project, &str) -> Execs) {
  ",
  )
  .run();
  + assert!(paths::home().join(".cargo/registry/CACHEDIR.TAG").is_file());
  p.change_file(
  "a/Cargo.toml",
  