Merge #16918: test: Make PORT_MIN in test runner configurable

fa69588537 test: Make PORT_MIN in test runner configurable (MarcoFalke)

Pull request description:

  This is needed when some ports in the port range are used by other processes. Note that simply assigning the ports dynamically does not work:

  * We spin up several nodes per test (each node gets its own port)
  * We run several tests in parallel

  So to avoid nodes from different tests colliding on ports, the port assignment must be deterministic (can not be dynamic).

  Fixes: #10869

ACKs for top commit:
  practicalswift:
    ACK fa69588537 -- diff looks correct
  promag:
    ACK fa69588537.

Tree-SHA512: e79adb015e7de79064e2d14336c38bc9672bd779ad6c52917721897e73f617c39d32c068a369c26670002a6c4ab95a71ef3a6878ebdd9710e02f410e2f7bcd14

test/functional/test_framework/util.py

@@ -7,13 +7,13 @@
 from base64 import b64encode
 from binascii import unhexlify
 from decimal import Decimal, ROUND_DOWN
+from subprocess import CalledProcessError
 import inspect
 import json
 import logging
 import os
 import random
 import re
-from subprocess import CalledProcessError
 import time
 
 from . import coverage
@@ -235,10 +235,11 @@ def wait_until(predicate, *, attempts=float('inf'), timeout=float('inf'), lock=N
 # The maximum number of nodes a single test can spawn
 MAX_NODES = 12
 # Don't assign rpc or p2p ports lower than this
-PORT_MIN = 11000
+PORT_MIN = int(os.getenv('TEST_RUNNER_PORT_MIN', default=11000))
 # The number of ports to "reserve" for p2p and rpc, each
 PORT_RANGE = 5000
 
+
 class PortSeed:
     # Must be initialized with a unique integer for each process
     n = None