Support for python (behave)

[alef75]

🤔 What's the problem you're trying to solve?

It could be great if also python could be supported.
we are sing python behave.
It's already great to have a full working gherkin editor like this in eclipse

✨ What's your proposed solution?

It would be noce to have also some feature like the current java support have

⛏ Have you considered any alternatives or workarounds?

No response

📚 Any additional context?

No response

[jenisys]

@alef75
FYI: There are some minor differences between behave Gherkin grammar and the cucumber Gherkin grammar:

• behave supports Rule Background and inheriting or overriding of Feature Background (steps) based on Gherkin v6
• cucumber Gherkin grammar initially supported Rule Background
• AFAIK: After the discussion of inheriting or overriding Feature Background (steps), this was removed again in a newer Cucumber Gherkin version.

[mpkorstanje]

@jenisys Gherkin supports rule backgrounds:

https://github.com/cucumber/gherkin/blob/main/testdata/good/rule.feature

Their steps are merged:

https://github.com/cucumber/gherkin/blob/main/testdata/good/rule.feature.pickles.ndjson

[jenisys]

@mpkorstanje Thanks for this correction.

[laeubi]

@alef75 it would be great to have more backends supported but as I'm not using cucumber with python I would need some help (maybe I can ask copilote as well but usually its better to feed it with concrete details) so here are some things to get this started:

1. What kind of files are used? also .feature? If yes it should already be possible to open these and getting Gherking syntax validation.
2. How do one run cucumber with python? What needs to be installed on the system or can it download a standalone executable somewhere?
3. Does it support plugins, and if yes would you be willing to help writing a remote-connector plugin?
4. How does it matches glue-code, e.g. is there already some python tooling around for eclipse we should integrate with?

[alef75]

Before all , thank you for your response.

1. only .feature for the gherkin and .py for the python sources. we are already using cucumber-eclipse plugin for editing our .feature files and it works great syntax highlight, auto complete and formatter are great.
2. we currently use a standard terminal from from the feature directory and run the command "behave xxx.feature" we have python and the behave python package already installed in our system.
3. I don't understand the question sorry..., I'm not familiar with eclipse development
4. for the python coding we are using pydev elise plugin. Behave wants step files inside the features/steps folder, we have a convention where we put a name_step.py for each name.feature file, but behave have no constrains about where to put the gherking steps automation glue code.

I think that a first step could be a way to manage the glue code, for example jump from the feature to the python steps and viceversa..
what do you think?

[laeubi]

Glue code matching is actually the most tricky part usually. What could be a first tep and is maybe quite easy is having support for right-click > run as. This is really not much more than a bit of an UI and then execute a system command (mostly) so is "behave" just an executable / system command? Is it a python script? Can we assume the user has installed this on their system or do we need to ship something with it?

[laeubi]

@alef75 I have now created a branch for this that includes pydev in the target and the product here:

• Add first native python support #564

now I can create pydev stuff so what should I choose here for a really simply example? So would one usually choose "PyDev Project"?

[alef75]

yes, it should be the first thing to choose.
I can sen you a simple example

[laeubi]

@alef75 we have an example folder here:

https://github.com/cucumber/cucumber-eclipse/tree/main/examples

would be great if you can create a PR with something similar so we have a python example.

[laeubi]

@mpkorstanje or @alef75 do you know if behave supports "plugins" like Cucumber-JVM does?

As an example this is the java plugin that just listen for events/messages that fly around during execution:

https://github.com/cucumber/cucumber-eclipse/blob/main/io.cucumber.eclipse.java.plugins/src/io/cucumber/eclipse/java/plugins/CucumberEclipsePlugin.java

[alef75]

For what I know there aren't any official plugin mechanism, like the one in the exemple you provide
Some extensions may be implemented via the formatters:
behave -f allure_behave.formatter:AllureFormatter -o ReportFileName (we use allure reports)

other extension point my be the hooks in the environment.py file:
Environment Hooks (environment.py)
This is the most commonly used approach for extending behave. The environment.py file provides hooks at various execution points:
pythondef before_all(context):
# Runs once before everything

def before_feature(context, feature):
# Runs before each feature

def before_scenario(context, scenario):
# Runs before each scenario

def before_step(context, step):
# Runs before each step

[laeubi]

Basically for the next step we would need:

1. Execute behave in a "dry run" and collect all discovered glue-code mappings and print them into a text file
2. Execute behave in a real run and every time a test start/end we need to append to a text file

would this be possible without needing the user to modify its test? I assume users are not so happy if we change their environment.py file maybe?

[alef75]

what about running behave and redirect to a file ?

1. dry run : behave --dry-run --format steps --no-summary -o codeMApping.txt
2. run : behave --format steps --no-summary > codeMApping.txt

but for point 2 I don't understand what you need, can you give an example ?

[laeubi]

@alef75 thanks for your suggestion, what ever works best, just assume I know nothing about behave and its options features :-)

So your suggestion with running it to redirect to a file seems doable, I assume it otherwise just prints to system-out as well?

but for point 2 I don't understand what you need, can you give an example ?

If you run a test (with cucumber-jvm) you get live results in the unit-test view, so you don't have to wait for the full suite to finish (we also use this to support breakpoints in feature files but that's a different story) and this works the following way:

• Cucumber jvm allows plugins (for formats and alike) to be given to the run and then gets events as JSON (e.g. test run started and so on)
• We have a plugin that connects to a socket and each time it recive such event write it to the output stream
• On the Eclipse-Plugin side we read these json messages an update the view

So the question would be if such "eventing" (at best following cucumber-messages format) as well, at laest there seems to be a python variant: https://github.com/cucumber/messages/tree/main/python