In the lean and agile world anything that produces value for the client is a good thing, everything else should be carefully scrutinized before carried out. This doesn’t mean you shouldn’t produce any documentation, it just means you should produce only the documentation that someone is likely to read. It doesn't mean you shouldn't produce any automated tests, it just means you should make sure you produce them in such a way you optimize value during the development period and for future maintenance. To do this right you need to understand which part of the project organization is producing direct value for the client and which part is supporting the Value Producers.
In many projects you could find three groups of Value Producers: programmers who produce code that builds the product, testers who make sure the product does what it is supposed to do and technical writers who produce the user documentation. Everyone else, requirements analysts, architects, designers, etc, are usually in a supportive role. The Supporters does not themselves produce anything of direct value to the client, however that doesn’t mean that their work is not important. It is. As long as they make it easier for the Value Producers to do their work, now and in the future.
That said one of the challenges in running an efficient agile project is to understand who is supporting who and how to make it as easy as possible to produce maximized value for the client. In order to do that you first need to understand what deliverables (both artifacts and activities) that produce value to the client. In some projects the client might get great value from the structuring and questioning on business processes done by the requirements analysts in order to define the system requirements. In other projects the client is perfectly clear on their business and the requirements specs are only needed to formally document the systems functionality and drive testing. Next you remove any activity or artifact that does not add value to the client or is invaluable in order to support efficient value production and make sure everyone inside and outside of the project understands their role and for whom they are supposed to produce value, in other words: if they are a Value Producer or a Supporter.