diff --git a/tests/unit/test_ptx_constraints_runner.py b/tests/unit/test_ptx_constraints_runner.py
new file mode 100644
index 00000000..1cc2f6b1
--- /dev/null
+++ b/tests/unit/test_ptx_constraints_runner.py
@@ -0,0 +1,18 @@
+"""Runner: test constraint approaches in separate processes."""
+import subprocess
+import sys
+
+for approach in ["r_r", "bitcast", "via_bitcast"]:
+    print(f"\n{'='*50}")
+    print(f"Testing: {approach}")
+    print(f"{'=i'*25}")
+    result = subprocess.run(
+        [sys.executable, "tests/unit/test_ptx_constraints.py", approach],
+        capture_output=True,
+        text=True,
+        timeout=120,
+    )
+    print(result.stdout)
+    if result.stderr:
+        print(f"STDERR (last 300): ...{result.stderr[-300:]}")
+    print(f"Exit code: {result.returncode}")