From ea07158eb86e92f5aa0d504ae52a8907a3869768 Mon Sep 17 00:00:00 2001
From: "Kevin R. Thornton" <krthornt@uci.edu>
Date: Fri, 17 Apr 2026 13:10:22 -0700
Subject: [PATCH] test: exception visibility in Python

---
 python_example/maketrees/python/maketrees/__init__.py | 1 +
 python_example/maketrees/src/lib.rs                   | 6 ++++++
 python_example/maketrees/tests/test_maketrees.py      | 9 +++++++++
 3 files changed, 16 insertions(+)

diff --git a/python_example/maketrees/python/maketrees/__init__.py b/python_example/maketrees/python/maketrees/__init__.py
index 0b1333f..192f65e 100644
--- a/python_example/maketrees/python/maketrees/__init__.py
+++ b/python_example/maketrees/python/maketrees/__init__.py
@@ -1,6 +1,7 @@
 import tskit
 
 from ._maketrees import maketrees
+from ._maketrees import raise_error
 
 
 def make_treeseq_with_metadata() -> tskit.TreeSequence:
diff --git a/python_example/maketrees/src/lib.rs b/python_example/maketrees/src/lib.rs
index 9f59544..b5ef35d 100644
--- a/python_example/maketrees/src/lib.rs
+++ b/python_example/maketrees/src/lib.rs
@@ -64,4 +64,10 @@ mod maketrees {
         };
         Ok(holder.into_python_tables(py)?)
     }
+
+    #[pyfunction]
+    fn raise_error(py: Python<'_>) -> PyResult<Py<PyAny>> {
+        let holder = tskit2tskit::SharedTableCollection::new(py, f64::NAN)?;
+        Ok(holder.into_python_tables(py)?)
+    }
 }
diff --git a/python_example/maketrees/tests/test_maketrees.py b/python_example/maketrees/tests/test_maketrees.py
index a71452f..f959eb2 100644
--- a/python_example/maketrees/tests/test_maketrees.py
+++ b/python_example/maketrees/tests/test_maketrees.py
@@ -21,3 +21,12 @@ def test_metadata():
     ts = maketrees.make_treeseq_with_metadata()
     m = ts.mutation(0).metadata
     assert m['data'] == "I am a mutation"
+
+
+def test_raise():
+    try:
+        _ = maketrees.raise_error()
+    except RuntimeError:
+        pass
+    except _:
+        raise ValueError("expected RuntimeError")