test: assert logging output

Author: jslee02

python/tests/unit/common/test_logging.py

@@ -2,19 +2,39 @@
 import pytest
 
 
-def test_basics():
+def assert_logged(capsys, *messages: str) -> None:
+    """Read captured logs and ensure *messages* appear in the output."""
+    captured = capsys.readouterr()
+    output = captured.out + captured.err
+    for msg in messages:
+        assert msg in output, f"{msg!r} not found in captured output"
+
+
+def test_basics(capsys):
     dart.common.trace("trace log")
     dart.common.debug("debug log")
     dart.common.info("info log")
     dart.common.warn("warn log")
     dart.common.error("error log")
     dart.common.fatal("fatal log")
 
+    assert_logged(
+        capsys,
+        "trace log",
+        "debug log",
+        "info log",
+        "warn log",
+        "error log",
+        "fatal log",
+    )
 
-def test_arguments():
+
+def test_arguments(capsys):
     val = 10
     dart.common.info("Log with param '{}' and '{}'".format(1, val))
 
+    assert_logged(capsys, "Log with param '1' and '10'")
+
 
 if __name__ == "__main__":
     pytest.main()