Testing commands after parsing option but before running

[sschuberth]

While reading through https://ajalt.github.io/clikt/testing/#custom-testing I was wondering whether it's easily possible to test the state of a command after parsing has happened and all options have been initialized, but before run() is called. On a related note, in this context it seems a bit odd that parse() does not actually just parse, but also calls run() underneath.

[ajalt]

There is no state in between parsing and running. A command is run as soon as a subcommand token is encountered (before parsing the subcommand's tokens). That way a parent command can print some output or a custom usage error etc. even if there are parse errors further down the line.

[sschuberth]

There is no state in between parsing and running.

Not right now, yes 😀 But I was implying that a refactoring (e.g. something that exposes the canRun parameter to callers) could introduce such a state. But I'm completely fine if you deem this to not be feasible, and close this issue!

[ajalt]

What's the use case? If you disable running for tests, it seems like you aren't testing your app, you're just testing Clikt.

[sschuberth]

I guess you're half-right, I'd be testing the configuration of clikt within my app. The concrete use-case arose when fixing this bug in our app where a default value for the rulesFile option was always applied, but that should only happen if rulesResource is not given. In a test that has access to the options but does not run the command I could have simply verified that rulesFile is null if rulesResource is set.

[pedroteixeira]

Also would like to re-use an existing command class in tests, but calling a different method instead of run, but using the same state option values.

Basically, if it's possible to instantiate the command class and set the option values by code? instead of using .parse

Any hints how to achieve? thanks

[ajalt]

@pedroteixeira no, I would suggest using parse

[pedroteixeira]

Ok, I think one way is to actually add an option such as "dryRun" and handle in the run() method.

But please let us know if there any tricks (perhaps with .context { } ?) that would allow one to override / define values for the option delegates by code :pray: (without need to using current parse) -- but I understand I am probably just thinking about the simple option cases (no sub commands, etc)

[ajalt]

If you need to set values from test code without changing your commands or writing a command line, you can set a valueSource in your tests. Something like:

val testValues = MapValueSource(mapOf("my-option" to "value"))
MyCommand().context { valueSource = testValues }.parse(emptyList())

I don't plan on building in a dry-run capability, so I'll close this issue.