diff --git a/bin/tests/system/isctest/__main__.py b/bin/tests/system/isctest/__main__.py
index 2b82a81d46..d1be74c727 100644
--- a/bin/tests/system/isctest/__main__.py
+++ b/bin/tests/system/isctest/__main__.py
@@ -9,9 +9,16 @@
 # See the COPYRIGHT file distributed with this work for additional
 # information regarding copyright ownership.
 
-from .vars import ALL
+import logging
+
+from . import log
+from .vars import ALL, init_vars
 
 
 if __name__ == "__main__":
+    # use root logger as fallback - we're not interested in proper logs here
+    log.basic.LOGGERS["conftest"] = logging.getLogger()
+
+    init_vars()
     for name, value in ALL.items():
         print(f"export {name}={value}")
diff --git a/bin/tests/system/isctest/log/basic.py b/bin/tests/system/isctest/log/basic.py
index b3987b27f9..67121d2e24 100644
--- a/bin/tests/system/isctest/log/basic.py
+++ b/bin/tests/system/isctest/log/basic.py
@@ -14,7 +14,6 @@ from pathlib import Path
 from typing import Dict, Optional
 
 
-CONFTEST_LOGGER = logging.getLogger("conftest")
 LOG_FORMAT = "%(asctime)s %(levelname)7s:%(name)s  %(message)s"
 
 LOGGERS = {
diff --git a/bin/tests/system/isctest/vars/algorithms.py b/bin/tests/system/isctest/vars/algorithms.py
index 56f3edc62c..26bcc579f8 100644
--- a/bin/tests/system/isctest/vars/algorithms.py
+++ b/bin/tests/system/isctest/vars/algorithms.py
@@ -129,9 +129,11 @@ def is_crypto_supported(alg: Algorithm) -> bool:
             cwd=tmpdir,
             check=False,
             stdout=subprocess.DEVNULL,
+            stderr=subprocess.PIPE,
         )
         if proc.returncode == 0:
             return True
+        log.debug(f"dnssec-keygen stderr: {proc.stderr.decode('utf-8')}")
         log.info("algorithm %s not supported", alg.name)
         return False