From c9cce0a7f66e5abe6a94704eb478e0dc52a29f13 Mon Sep 17 00:00:00 2001
From: Will Ayd <william.ayd@icloud.com>
Date: Sun, 1 Apr 2018 22:45:41 -0700
Subject: [PATCH] Tests: Add Metaclass for BitcoinTestFramework
BitcoinTestFramework instructs developers in its docstring to override
`set_test_params` and `run_test` in subclasses while being sure NOT to
override `__init__` and `main` . This change adds a metaclass to ensure
that developers adhere to that protocol, raising a ``TypeError`` in
instances where they have not.
closes #12835
---
.../test_framework/test_framework.py | 24 ++++++++++++++++++-
1 file changed, 23 insertions(+), 1 deletion(-)
diff --git a/test/functional/test_framework/test_framework.py b/test/functional/test_framework/test_framework.py
index 543643f27..96ce290ab 100755
--- a/test/functional/test_framework/test_framework.py
+++ b/test/functional/test_framework/test_framework.py
@@ -41,7 +41,28 @@ TEST_EXIT_PASSED = 0
TEST_EXIT_FAILED = 1
TEST_EXIT_SKIPPED = 77
-class BitcoinTestFramework():
+
+class BitcoinTestMetaClass(type):
+ """Metaclass for BitcoinTestFramework.
+
+ Ensures that any attempt to register a subclass of `BitcoinTestFramework`
+ adheres to a standard whereby the subclass overrides `set_test_params` and
+ `run_test` but DOES NOT override either `__init__` or `main`. If any of
+ those standards are violated, a ``TypeError`` is raised."""
+
+ def __new__(cls, clsname, bases, dct):
+ if not clsname == 'BitcoinTestFramework':
+ if not ('run_test' in dct and 'set_test_params' in dct):
+ raise TypeError("BitcoinTestFramework subclasses must override "
+ "'run_test' and 'set_test_params'")
+ if '__init__' in dct or 'main' in dct:
+ raise TypeError("BitcoinTestFramework subclasses may not override "
+ "'__init__' or 'main'")
+
+ return super().__new__(cls, clsname, bases, dct)
+
+
+class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
"""Base class for a bitcoin test script.
Individual bitcoin test scripts should subclass this class and override the set_test_params() and run_test() methods.
@@ -432,6 +453,7 @@ class BitcoinTestFramework():
for i in range(self.num_nodes):
initialize_datadir(self.options.tmpdir, i)
+
class SkipTest(Exception):
"""This exception is raised to skip a test"""
def __init__(self, message):