Optional substring in steps

[lu-maca]

Hi,

is it possible to create a step definition that can contain an optional field and such that returns a boolean, true if the field is present and false if not?

For example:

@step("I {optional_field:bool} post something")
def step_impl(context, optional_field):
    ...

When I post something

would result in optional_field=False, but

When I successfully post something

would result in optional_field=True.

POSSIBLE SOLUTION:
The only way I've found to mimic this behaviour is the following:

@step("I {success} post something")
@step("I post something")
def step_impl(context, success=None):
    optional_field = False
    if success == "successfully":
        optional_field = True

but this is not really robust, because if I write the step:

When I try to post something

it will match the step above.
However I would like to have a step that accepts only "successfully" as optional field.

[jenisys]

You can use optional types by using special registered types (simplified by using the parse_type module).

NOTES:

• Your example: If you do not specify a type in a parse-expression, the corresponding regular-expression is normally greedy and will match as much as possible.
• The simplest solution is normally the cardinality-fields expression, like: {number:Number?} for an optional number using the cfparse matcher. It automatically implicitly generates patterns for other cardinalities by using the registered types/patterns with cardinality=1.

SEE:

• https://behave.github.io/behave.example/datatype/index.html
• https://behave.github.io/behave.example/datatype/cardinality_zero_or_one.html

[lu-maca]

Thank you!