Implemented '$concatArrays' aggregation pipeline operator by lmoretto · Pull Request #672

Implemented '$concatArrays' aggregation pipeline operator by lmoretto · Pull Request #672 · mongomock/mongomock

This PR implements the $concatArrays aggregation pipeline operator.

Hi @pcorpet,
I just saw that the codecov check fails.

However I think this is caused by the fact that, having now implemented $concatArrays, the following piece of code is no longer hit by existing test cases:

	raise NotImplementedError(
	"Although '%s' is a valid array operator for the "
	'aggregation pipeline, it is currently not implemented '
	'in Mongomock.' % operator)

Do you think I should change something?

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Thanks for your contribution. yes please make sure to switch the testing code to still cover the NotImplemented branch (with another array operator).

Also I have few other test cases that I'd like you to add.

Hi @pcorpet, I applied the requested changes ;)

		}
		}
		]
		with self.assertRaises(OperationFailure):

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Please use the self.cmp.compare_exceptions.aggregate(pipeline_parameter_not_array) function, same below. This ensures we use the same type of error in Pymongo and in mongomock without the need of the extra code.

Thanks a lot for the feature, I'm merging.

Great, thank you for merging this and for the great work you are doing with this project.

In the next few days i plan to also implement $map and $reduce aggregation operators.
Will a single PR for both operators be ok, or do you prefer two separate ones?