Support brotlicffi in tests

[mgorny]

While the package itself can work with either brotli or brotlicffi, tests/test_decoders.py explicitly requires brotli. We're currently working on having all packages support brotlicffi in Gentoo, since brotli doesn't work reliably on PyPy3. Could you please consider making the test accept brotlicffi as well?

I suppose the simplest way would be to reuse the existing logic, i.e.:

from httpx._compat import brotli

I can submit a PR for that.

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• Initially raised as discussion Support for brotlicffi in tests #2903

[karpetrosyan]

I can submit a PR for that.

Yes, that would be great!

[tomchristie]

Alternate options:

• We could just always brotlicffi in the tests instead of brotli. (Because we value platform independence over c-performance here.)
• We don't actually need the brotli dependency in the tests at all, so we could drop it outright. We only use it on 3 lines, each of which we can replace using the byte encoding directly...

-    compressed_body = brotli.compress(body)
+    compressed_body = b"\x8b\x03\x80test 123\x03"

-    body = b"test 123"
-    compressed_body = brotli.compress(body)[3:]
+    compressed_body = b"invalid"

[mgorny]

* We could just always `brotlicffi` in the tests instead of `brotli`. (Because we value platform independence over c-performance here.)

That would work for us since we care about brotlicffi only but I think it'd be better to match the implementation used by httpx in the more general case.

* We don't actually need the `brotli` dependency in the tests at all, so we could drop it outright. We only use it on 3 lines, each of which we can replace using the byte encoding directly...

Yeah, that would work for me.

Please let me know which approach you prefer and I can do it.

[tomchristie]

Please let me know which approach you prefer and I can do it.

I'd suggest the second.