Merge #19315: [tests] Allow outbound & block-relay-only connections in functional tests.

b4dd2ef8009703b81235e2d9a2a736a3a5e8152f [test] Test the add_outbound_p2p_connection functionality (Amiti Uttarwar)
602e69e4278f0ed25c65fb568ab395e4c7ca9ceb [test] P2PBlocksOnly - Test block-relay-only connections. (Amiti Uttarwar)
8bb6beacb19864b1fca766b3e153349a31dc0459 [test/refactor] P2PBlocksOnly - Extract transaction violation test into helper. (Amiti Uttarwar)
99791e7560d40ad094eaa73e0be3987581338e2d [test/refactor] P2PBlocksOnly - simplify transaction creation using blocktool helper. (Amiti Uttarwar)
3997ab915451a702eed2153a0727b0a78c0450ac [test] Add test framework support to create outbound connections. (Amiti Uttarwar)
5bc04e8837c0452923cebd1b823a85e5c4dcdfa6 [rpc/net] Introduce addconnection to test outbounds & blockrelay (Amiti Uttarwar)

Pull request description:

  The existing functional test framework uses the `addnode` RPC to spin up manual connections between bitcoind nodes. This limits our ability to add integration tests for our networking code, which often executes different code paths for different connection types.

  **This PR enables creating `outbound` & `block-relay-only` P2P connections in the functional tests.** This allows us to increase our p2p test coverage, since we can now verify expectations around these connection types.

  This builds out the [prototype](https://github.com/bitcoin/bitcoin/issues/14210#issuecomment-527421978) proposed by ajtowns in #14210. 🙌🏽

  An overview of this branch:
  - introduces a new test-only RPC function `addconnection` which initiates opening an `outbound` or `block-relay-only` connection. (conceptually similar to `addnode` but for different connection types & restricted to regtest)
  - adds `test_framework` support so a mininode can open an `outbound`/`block-relay-only` connection to a `P2PInterface`/`P2PConnection`.
  - updates `p2p_blocksonly` tests to create a `block-relay-only` connection & verify expectations around transaction relay.
  - introduces `p2p_add_connections` test that checks the behaviors of the newly introduced `add_outbound_p2p_connection` test framework function.

  With these changes, there are many more behaviors that we can add integration tests for. The blocksonly updates is just one example.

  Huge props to ajtowns for conceiving the approach & providing me feedback as I've built out this branch. Also thank you to jnewbery for lots of thoughtful input along the way.

ACKs for top commit:
  troygiorshev:
    reACK b4dd2ef8009703b81235e2d9a2a736a3a5e8152f
  jnewbery:
    utACK b4dd2ef8009703b81235e2d9a2a736a3a5e8152f
  MarcoFalke:
    Approach ACK b4dd2ef8009703b81235e2d9a2a736a3a5e8152f 🍢

Tree-SHA512: d1cba768c19c9c80e6a38b1c340cc86a90701b14772c4a0791c458f9097f6a4574b4a4acc7d13d6790c7b1f1f197e2c3d87996270f177402145f084ef8519a6b

0 files changed, 0 insertions, 0 deletions