Bash, back to the seventies

Yesterday I decided I needed some tests. Overnight, simple curl in a bash script seemed appropriate to test a REST API.

I created a new test configuration in grunt-preprocess. It generates some duplicated code, that I was unable not remove. I added grunt-shell to be able to launch scripts from grunt.

I had it all working in half an hour. Grunt is ok, but the ecosystem looks a bit young, with a lot of extensions providing the same service (grunt-exec, grunt-shell, grunt-run...), some allegedly no longer maintained.

Anyway, now on to my script.

Bash bashing

The shell script first calls mysql to create and populate a test database. I used mysql_config_editor to persist a MySql login configuration and avoid the "Using a password on the command line interface can be insecure" warnings when setting the password from the command line.

I created an assert bash function to check the JSON returned by a query, and an assertError to check the http return code of invalid requests (hint: curl -s -o /dev/null -w "%{http_code}"). A nice DSL with one-liner tests:

assert "POST" "user" "$USER" '{"id":"1","role":"user","token":".."}'
assertError "POST" "user" "$INVALID_USER" 403

But bash was not helping me. One line sums it up:

if [ "$RESULT" != "$EXPECTED" ]; then

where you learn that [ is not just a funny parenthesis, but an alias to the test command, which expects ] as it last argument. This explains why you need this ; at the end to separate the then. And do not try to remove any of the space characters here, they are all required. Same thing for the quotes, which prevent new spaces from appearing.

Bash is a dinosaur, coming from the seventies, when you were so proud you could format your 720k floppy using the command line. I knew it, but my script was short, and all I needed was to get these two assert methods running.

And then a test fails

In this test, I give a new type of header parameter to curl, but it manages to mess with the parameters and their quotes. When I echo the command and then run it in a shell, I get the correct result. But when bash runs it, I can see on the server log that the header parameters are wrong, maybe because it added some quotes this time.

I've spent more than half a day on these tests, and all the bugs I've found so far were in the tests.