println! in steps is not working as expected.

[antonkol]

i have few println! inside steps and when i am executing tests information in println! appears before all Cucumber log.

Something like this:

some info 1
some info 2

 Feature: Some feature
   Scenario Outline: Some scenario outline
       Given
       And
   Scenario Outline: Some scenario outline
      Given
       And

Is there a way to output println! below appropriate step ?

Something like this:

 Feature: Some feature
   Scenario Outline: Some scenario outline
       Given
          some info 1
       And
   Scenario Outline: Some scenario outline
      Given
          some info 2
       And

[ilslv]

@antonkol unfortunately this is feature isn't supported. The main reason behind it is a concurrent Scenario execution. So to support this feature we somehow need to come up with mechanism to intercept output of the println! macro, somehow understand which step it belongs to from the context of the Step function, store all this data and only when the time is right output it.
Maybe this is possible with custom println! and dbg! macros, but I believe that it's not possible with default ones.

I'll leave this issue open with a rfc tag and give it a thought a bit more.

[tyranron]

@ilslv may be a clear explanation of how to run tests, so the custom output will appear naturally, will do the job?

Is --concurrency=1 will be enough? Or we should also remove writer::Normalized from pipeline? Could you provide an example? I'll include the one to the Book in #171.

[ilslv]

@tyranron

Is --concurrency=1 will be enough? Or we should also remove writer::Normalized from pipeline?

To achieve natural output, you'll need to do the following steps:

1. Create writer::Basic::raw with Coloring::Never to avoid interference with pretty-printed output

writer::Basic::raw(stdout(), writer::Coloring::Never, false)
    .summarized()

2. You'll need custom Writer like AssertNormalized which implements Normalized for any Writer, but does nothing. This isn't supplied by crate yet, but maybe we should?
3. Set max_concurrent_scenarios() to 1

Full example:

let res = World::cucumber()
    .max_concurrent_scenarios(1)
    .with_writer(writer::AssertNormalized(
//                       ^^^^^^^^^^^^^^^^ doesn't exist yet. 
        writer::Basic::raw(stdout(), writer::Coloring::Never, false)
            .summarized(),
    ))
    .with_cli(cli)
    .run_and_exit("tests/features/wait");

Output for wait test with dbg! and all steps above

Feature: Basic
  Scenario: 1 sec
[tests/wait.rs:61] world.0 = 1
   ✔> Given 1 sec
[tests/wait.rs:61] world.0 = 2
   ✔  Given 1 sec
[tests/wait.rs:61] world.0 = 3
   ✔  When 1 sec
   ?  Then unknown
      Step skipped: /Users/work/Work/cucumber/tests/features/wait/rule.feature:9:5
...

So even with all those steps we first see output of the dbg! and only then step result.

[tyranron]

@ilslv

So even with all those steps we first see output of the dbg! and only then step result.

It's not a problem though, as we have them close to the performed step.

2. You'll need custom Writer like AssertNormalized which implements Normalized for any Writer, but does nothing. This isn't supplied by crate yet, but maybe we should?

Hmmm, I think we should add them, along with ext-helpers, so we have:

let res = World::cucumber()
    .max_concurrent_scenarios(1)
    .with_writer(
        writer::Basic::raw(stdout(), writer::Coloring::Never, false)
            .summarized()
            .assert_normalized(),
    )
    .with_cli(cli) // do we really need this line here? It should work without it.
    .run_and_exit("tests/features/wait");

[ilslv]

@tyranron

.with_cli(cli) // do we really need this line here? It should work without it.

Oh, of corse no, left it by mistake

Hmmm, I think we should add them, along with ext-helpers, so we have:

Ok

[tyranron]

Done. Now it's only left to describe in new Book in #171.

[tyranron]

Now it's only left to describe in new Book in #171.

Done.