tests: Add logger config with fixture

Pyln logger's configuration was unexpectedly being overwritten by the root logger during the autogenerated examples test, complicating error debugging.

We resolved this by introducing a pytest fixture to reapply the logger configuration before the tests executes.

Changelog-None.

Fixes: #8023

doc/contribute-to-core-lightning/coding-style-guidelines/writing-json-schemas.md

@@ -94,7 +94,7 @@ preventing accidental overwrites from unrelated tests.
 	where `n` can be any number of repetitions. OR by manually running the test multiple times with:
 
 	```bash
-	rm -rf /tmp/ltests* && make -s && VALGRIND=0 TIMEOUT=40 TEST_DEBUG=1 GENERATE_EXAMPLES=1 pytest -vvv tests/autogenerate-rpc-examples.py
+	rm -rf /tmp/ltests* && make -s && VALGRIND=0 TIMEOUT=40 TEST_DEBUG=1 GENERATE_EXAMPLES=1 pytest -vvv -s tests/autogenerate-rpc-examples.py
 	```
 
 	- Identify changing values, and add them to `REPLACE_RESPONSE_VALUES`:
@@ -117,7 +117,7 @@ environment variable with a comma-separated list of method names. Eg. `REGENERAT
 only regenerate examples for the `getinfo` and `connect` RPCs.
 2. To regenerate specific examples, set the REGENERATE environment variable:
 ```bash
-REGENERATE='getinfo,connect' VALGRIND=0 TIMEOUT=10 TEST_DEBUG=1 GENERATE_EXAMPLES=1 pytest -vvv tests/autogenerate-rpc-examples.py
+REGENERATE='getinfo,connect' VALGRIND=0 TIMEOUT=10 TEST_DEBUG=1 GENERATE_EXAMPLES=1 pytest -vvv -s tests/autogenerate-rpc-examples.py
 ```
 3. Logs are saved in `tests/autogenerate-examples-status.log`, and JSON data is in `tests/autogenerate-examples.json`.
 4. Run `make` after the script completes to ensure schema updates are applied in other places too, such as `...msggen/schema.json`.
@@ -127,4 +127,4 @@ REGENERATE='getinfo,connect' VALGRIND=0 TIMEOUT=10 TEST_DEBUG=1 GENERATE_EXAMPLE
 
 1. Sip whenever you have an additional comma at the end of a sequence.
 2. Sip whenever you omit a comma in a sequence because you cut & paste.
-3. Skull whenever you wish JSON had comments.
+3. Skull whenever you wish JSON had comments.

tests/autogenerate-rpc-examples.py

@@ -297,15 +297,6 @@
 
 if os.path.exists(LOG_FILE):
     open(LOG_FILE, 'w').close()
-
-logging.basicConfig(level=logging.INFO,
-                    format='%(asctime)s - %(levelname)s - %(message)s',
-                    datefmt='%H:%M:%S',
-                    handlers=[
-                        logging.FileHandler(LOG_FILE),
-                        logging.StreamHandler()
-                    ])
-
 logger = logging.getLogger(__name__)
 
 
@@ -2035,6 +2026,19 @@ def generate_list_examples(l1, l2, l3, c12, c23_2, inv_l31, inv_l32, offer_l23,
         raise
 
 
+@pytest.fixture(autouse=True)
+def setup_logging():
+    global logger
+    logger.setLevel(logging.DEBUG)
+    formatter = logging.Formatter("%(asctime)s - %(levelname)s - %(message)s", "%H:%M:%S")
+    stream_handler = logging.StreamHandler()
+    stream_handler.setFormatter(formatter)
+    logger.addHandler(stream_handler)
+    file_handler = logging.FileHandler(LOG_FILE)
+    file_handler.setFormatter(formatter)
+    logger.addHandler(file_handler)
+
+
 @unittest.skipIf(not GENERATE_EXAMPLES, 'Generates examples for doc/schema/lightning-*.json files.')
 def test_generate_examples(node_factory, bitcoind, executor):
     """Re-generates examples for doc/schema/lightning-*.json files"""
@@ -2055,9 +2059,9 @@ def list_all_examples():
                 for node in ast.walk(tree):
                     if isinstance(node, ast.Call) and isinstance(node.func, ast.Name) and node.func.id == 'update_example':
                         for keyword in node.keywords:
-                            if (keyword.arg == 'method' and isinstance(keyword.value, ast.Str)):
-                                if keyword.value.s not in methods:
-                                    methods.append(keyword.value.s)
+                            if (keyword.arg == 'method' and isinstance(keyword.value, ast.Constant)):
+                                if keyword.value.value not in methods:
+                                    methods.append(keyword.value.value)
                 return methods
             except Exception as e:
                 logger.error(f'Error in listing all examples: {e}')
@@ -2105,5 +2109,5 @@ def list_missing_examples():
         update_examples_in_schema_files()
         logger.info('All Done!!!')
     except Exception as e:
-        logger.error(e)
+        logger.error(e, exc_info=True)
         sys.exit(1)