tests: adapt to new linter

The Python test driver now uses 'pyflakes'.
Remove hacks that were needed for the 'black' linter.

test/lib/make-test-vm.nix

@@ -10,36 +10,16 @@ args:
 let
   test = pythonTesting.makeTest args;
 
-  fixedDriver = test.driver.overrideAttrs (old: let
-    # Allow the test script to have longer lines by fixing the call to the 'black'
-    # code formatter.
-    # The default width of 88 chars is too restrictive for our script.
-    parts = builtins.split ''/nix/store/[^ ]+/black '' old.buildCommand;
-    preMatch = builtins.elemAt parts 0;
-    postMatch = builtins.elemAt parts 2;
-  in {
-    # See `mkDriver` in nixpkgs/nixos/lib/testing-python.nix for the original definition of `buildCommand`
-    buildCommand = ''
-      ${preMatch}${pkgs.python3Packages.black}/bin/black --line-length 100 ${postMatch}
-    '';
-    # Keep reference to the `testDriver` derivation, required by `buildCommand`
-    testDriverReference = old.buildCommand;
-  });
-
-  # 1. Use fixed driver
-  # 2. Save test logging output
-  # 3. Add link to driver so that a gcroot to a test prevents the driver from
+  # 1. Save test logging output
+  # 2. Add link to driver so that a gcroot to a test prevents the driver from
   #    being garbage-collected
   fixedTest = test.overrideAttrs (_: {
     # See `runTests` in nixpkgs/nixos/lib/testing-python.nix for the original definition of `buildCommand`
     buildCommand = ''
       mkdir $out
-      LOGFILE=$out/output.xml tests='exec(os.environ["testScript"])' ${fixedDriver}/bin/nixos-test-driver
-      ln -s ${fixedDriver} $out/driver
+      LOGFILE=$out/output.xml tests='exec(os.environ["testScript"])' ${test.driver}/bin/nixos-test-driver
+      ln -s ${test.driver} $out/driver
     '';
-  }) // {
-    driver = fixedDriver;
-    inherit (test) nodes;
-  };
+  });
 in
   fixedTest

test/tests.py

@@ -1,6 +1,7 @@
 from collections import OrderedDict
 import json
 
+logger = machine.logger
 
 def succeed(*cmds):
     """Returns the concatenated output of all cmds"""
@@ -39,7 +40,7 @@ def wait_for_open_port(address, port):
         status, _ = machine.execute(f"nc -z {address} {port}")
         return status == 0
 
-    with log.nested(f"Waiting for TCP port {address}:{port}"):
+    with logger.nested(f"Waiting for TCP port {address}:{port}"):
         retry(is_port_open)
 
 
@@ -66,7 +67,7 @@ def run_tests():
         raise RuntimeError(f"The following tests are enabled but not defined: {enabled}")
     machine.connect()  # Visually separate boot output from the test output
     for test in to_run:
-        with log.nested(f"test: {test}"):
+        with logger.nested(f"test: {test}"):
             tests[test]()
 
 
@@ -150,9 +151,9 @@ def _():
                 f"Output of 'lightning-cli plugin list':\n{plugin_list}"
             )
         else:
-            log.log("Active clightning plugins:")
+            logger.log("Active clightning plugins:")
             for p in test_data["clightning-plugins"]:
-                log.log(os.path.basename(p))
+                logger.log(os.path.basename(p))
 
 
 @test("lnd")