@peter/integration test

[0g-peterzhb]

Why are these changes needed?

Checks

• I've made sure the lint is passing in this PR.
• I've made sure the tests are passing. Note that there might be a few flaky tests, in that case, please comment that they are not relevant.
• Testing Strategy
  • Unit tests
  • Integration tests
  • This PR is not tested :(

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This change is 

[peilun-conflux]

Reviewed 2 of 10 files at r1, 16 of 16 files at r2, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @0g-peterzhb)

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tests/da_test_framework/da_encoder.py line 50 at r2 (raw file):

    def wait_for_rpc_connection(self):
        time.sleep(3)

Is it possible to call some RPC method here to check if the RPC service has started?

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tests/da_test_framework/da_server.py line 56 at r2 (raw file):

            time.sleep(3)
        self.log.info(f'{self.grpc_url}')
        self.channel = grpc.insecure_channel(self.grpc_url)

same here