* Use tempdir for tests
* Rename tmp to tempdir
* Update Cargo.lock
* Update expect error message in run_command_and_kill
* Call with .path() rather than creating an string slice
* Call tempdir with arg instead of args
* Update tests/purge_chain_works.rs
Co-authored-by: Bastian Köcher <bkchr@users.noreply.github.com>
Make sure that --dev purge-chain is rejected
```
[0] [11:24:02] ~/r/polkadot master > ./target/debug/polkadot purge-chain --dev -y
"/home/cecile/.local/share/polkadot/chains/dev/db" did not exist.
[0] [11:25:36] ~/r/polkadot cecton-fix-invalid-argument-order > ./target/debug/polkadot --dev purge-chain -y
error: Found argument 'purge-chain' which wasn't expected, or isn't valid in this context
USAGE:
polkadot --dev
For more information try --help
```
pscott