Add test for multiline log

janus_core/log.py

@@ -38,6 +38,9 @@ def format(self, record: logging.LogRecord) -> str:
         str
             Formatted log message.
         """
+        # Replace "" with '' to prevent invalid wrapping
+        record.msg = record.msg.replace('"', "'")
+
         # Convert new lines into yaml list
         if len(record.msg.split("\n")) > 1:
             msg = record.msg

tests/test_md.py

@@ -6,6 +6,7 @@
 from ase.io import read
 import numpy as np
 import pytest
+import yaml
 
 from janus_core.md import NPH, NPT, NVE, NVT, NVT_NH
 from janus_core.mlip_calculators import choose_calculator
@@ -525,3 +526,34 @@ def test_atoms_struct(tmp_path):
         assert " | Epot/N [eV]" in lines[0]
         # Includes step 0
         assert len(lines) == 6
+
+
+def test_multiline_log(tmp_path):
+    """Test multiline log messages are written correctly."""
+    file_prefix = tmp_path / "nvt-T300"
+    log_path = tmp_path / "test.log"
+
+    single_point = SinglePoint(
+        struct_path=DATA_PATH / "NaCl.cif",
+        architecture="mace",
+        calc_kwargs={"model": MODEL_PATH},
+        log_kwargs={"filename": log_path, "force": True},
+    )
+
+    nvt = NVT(
+        struct=single_point.struct,
+        steps=2,
+        file_prefix=file_prefix,
+        rescale_every=5,
+        rescale_velocities=True,
+        log_kwargs={"filename": log_path, "filemode": "a"},
+    )
+    nvt.run()
+
+    assert log_path.exists()
+    with open(log_path, encoding="utf8") as log:
+        log_dicts = yaml.safe_load(log)
+
+    assert log_dicts[2]["level"] == "WARNING"
+    assert len(log_dicts[2]["message"]) == 2
+    assert "UserWarning: Velocities" in log_dicts[2]["message"][0]