Add a crate to test the in-browser light client.

[expenses]

At the moment, the wasm light client is at a high risk of being broken by incoming commits. This PR adds a simple test that makes sure the light client connects to peers and starts syncing. This requires #4880 to me merged first.

It's pretty messy, but I'm not sure if there's a great way to improve that.

[tomaka]

Of course also waiting to switch to published libp2p.

[TriplEight]

Firefox will be added to the CI env in paritytech/scripts#152

[expenses]

@tomaka Would you like to wait until libp2p/rust-libp2p#1454 is merged and libp2p 0.16.1 is published before merging this? I'm happy either way.

[tomaka]

Looks good to me, assuming you manage to make the test work.

[expenses]

I've merged in #5613.

[bkchr]

Still not working?

[expenses]

Still not working?

It worked once: https://gitlab.parity.io/parity/substrate/-/jobs/459858, but then when i re-ran that test it failed, with the only different being the port number that wasm-pack-test-runner randomly selects (I haven't noticed a pattern about which ports work and which don't though).

[bkchr]

Hmm :(

[bkchr]

@expenses Did you tried running it with verbose option enabled to better debug this?

[gavofyork]

@expenses ?

[TriplEight]

currently, it doesn't work with the chromedriver, working on it.

[TriplEight]

@expenses
tried with your new branch https://github.com/expenses/wasm-bindgen/tree/port-env-var with WASM_BINDGEN_TEST_ADDRESS set to 127.0.0.1:37351 (also with 9515).
It's reproducible with

docker run -it -v ~/cache/substrate:/ci-cache parity/rust-builder:latest
# and there 
export SCCACHE_DIR=/ci-cache/sccache
export CARGO_HOME=/ci-cache/cargo
export CARGO_TARGET_DIR=/ci-cache/targets/
export RUSTFLAGS="-Cdebug-assertions=y"
git clone https://github.com/paritytech/substrate .
git checkout ashley-browser-testing
export CARGO_TARGET_WASM32_UNKNOWN_UNKNOWN_RUNNER="wasm-bindgen-test-runner"
export WASM_BINDGEN_TEST_TIMEOUT=60
cargo +nightly test --target wasm32-unknown-unknown -p node-browser-testing -Z features=itarget

and
webdriver.json

{"goog:chromeOptions": {
    "args": [
      "--verbose",
      "whitelisted-ips=127.0.0.1",
      "--headless",
      "--disable-gpu",
      "--no-sandbox"
    ]
  }
}

It did not work:

logs

    Finished test [unoptimized + debuginfo] target(s) in 0.47s
     Running /ci-cache/targets/wasm32-unknown-unknown/debug/deps/node_browser_testing-3ef5d09ca18e450f.wasm
Set timeout to 60 seconds...
Running headless tests in Chrome on `http://127.0.0.1:9515/`
Try find `webdriver.json` for configure browser's capabilities:
Ok
Failed to detect test as having been run. It might have timed out.
output div contained:
    running 1 test

driver status: signal: 9                          
driver stdout:
    Starting ChromeDriver 80.0.3987.162 (f2c5dd6138153bb0658091205bd1a1717f16081a-refs/branch-heads/3987@{#1034}) on port 9515
    Only local connections are allowed.
    Please protect ports used by ChromeDriver and related test frameworks to prevent access by malicious code.

driver stderr:
    [1587141083.320][SEVERE]: bind() failed: Cannot assign requested address (99)

Error: some tests failed                          
error: test failed, to rerun pass '-p node-browser-testing --lib'

# 
root@83b8c00b60ca:/builds# chromedriver --whitelisted-ips=127.0.0.1 --verbose
Starting ChromeDriver 80.0.3987.162 (f2c5dd6138153bb0658091205bd1a1717f16081a-refs/branch-heads/3987@{#1034}) on port 9515
Remote connections are allowed by a whitelist (127.0.0.1).
Please protect ports used by ChromeDriver and related test frameworks to prevent access by malicious code.

Apparently, this setup does not read webdriver.json even though it tells that finds it:

Try find `webdriver.json` for configure browser's capabilities:
Ok

Proof:

in cargo test run there's Only local connections are allowed. and if run chromedriver --whitelisted-ips=127.0.0.1 it runs with Remote connections are allowed by a whitelist (127.0.0.1).
Native chromedriver's port is 9515
I have no clue how to pass flags to it, so I stuck with debug here.

[expenses]

@TriplEight Oh, thanks for figuring out how to make it reproducible!

[expenses]

I think I've finally gotten it to work 😊😊😊😊