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46 lines
1.8 KiB
46 lines
1.8 KiB
5 years ago
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title = "Things I Learnt The Hard Way - Tests Make Better APIs"
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date = 2019-06-19
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[taxonomies]
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tags = ["en-au", "book", "things i learnt", "unit tests", "layers", "apis"]
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Testing things in isolation may give a better view of your APIs.
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<!-- more -->
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When I spoke about [integration
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tests](/books/things-i-learnt/integration-tests) you may end up with the
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impression that I don't like unit tests[^1].
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Actually, I think they provide some good intrinsic values.
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For example, as mentioned before, they can provide a better look at the
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adherence to the design.
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But, at the same time, they give a better view of your internal -- and even
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external -- APIs.
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For example, you're writing the tests for the view layer -- 'cause, you know,
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we write everything in layers; layers on top of layers -- and you're noticing
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that you have to keep a lot of data (state) around to be able to make the
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calls to the controller. That's a sign that you may have to take a better look
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at the controller API.
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Not only that, but take, for example, the fact that you're working on a
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library -- which will be called by someone else -- and you're writing tests
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for the most external layer, the layer that will be exposed by the library.
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And, again, you're noticing that you have to keep a lot of context around,
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lots of variables, variables coming from different places and similar calls
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using parameters in different ways. Your tests will look like a mess, don't
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they? That's because the API _is_ a mess.
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Unit testing your layers makes you the _user_ of that layer API, and then you
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can see how much one would suffer -- or, hopefully, enjoy -- using that.
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[^1]: Again, let's ignore for a second that there are no "unit" in "unit
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tests"...
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{{ chapters(prev_chapter_link="/books/things-i-learnt/integration-tests", prev_chapter_title="Unit Tests Are Good, Integration Tests Are Gooder") }}
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