Add integration tests for RPC calls and runtime configuration

[maltekliemann]

We've had some RPC calls fail due to incorrect order of arguments and encoding problems, which can't easily be caught. Writing some integration tests might help here.

Also, @vivekvpandya pointed out that it might be a good idea to test the runtime configuration. For example, do the thresholds we define for the Advisory Committee really do what we think they do?

[maltekliemann]

@vivekvpandya Actually, wouldn't it be easier to write tests for the runtime configuration in runtime/?

[vivekvpandya]

@vivekvpandya Actually, wouldn't it be easier to write tests for the runtime configuration in runtime/? Yes I agree with you.

[maltekliemann]

MVP of integration tests should contain the following:

• Local node produces blocks and accepts transactions.
• Call filters work as expected.

I'd describe the long-term vision as follows: Our "unit" tests just use the other pallets as mocks, so they're basically integration tests. We may want to design our units tests to use actual mocks and move integration tests into runtime.

[sea212]

Local node produces blocks and accepts transactions.

This is planned to be part of the release automation CI https://github.com/zeitgeistpm/zeitgeist/issues/870

[maltekliemann]

Moving to next milestone because no one is assigned.