[df] Add Python test with empty list of filenames

bindings/pyroot/pythonizations/test/CMakeLists.txt

@@ -115,6 +115,8 @@ endif()
 # RDFDescription pythonization
 if (dataframe)
     ROOT_ADD_PYUNITTEST(pyroot_rdfdescription rdfdescription.py)
+
+    ROOT_ADD_PYUNITTEST(pyroot_pyz_rdataframe_misc rdataframe_misc.py)
 endif()
 
 # SOFIE-GNN pythonizations

bindings/pyroot/pythonizations/test/rdataframe_misc.py

@@ -0,0 +1,34 @@
+import cppyy
+import platform
+import unittest
+
+import ROOT
+
+
+class RDataFrameMisc(unittest.TestCase):
+    """Miscellaneous RDataFrame tests"""
+
+    def test_empty_filenames(self):
+        """
+        An empty list of filenames should be detected and the user should be informed
+        """
+        # See https://github.com/root-project/root/issues/7541 and
+        # https://bugs.llvm.org/show_bug.cgi?id=49692 :
+        # llvm JIT fails to catch exceptions on MacOS ARM, so we disable their testing
+        # Also fails on Windows 64bit for the same reason
+        if (
+            (platform.processor() != "arm" or platform.mac_ver()[0] == '') and not
+            (platform.system() == "Windows" and platform.architecture()[0] == "64bit")
+        ):
+            with self.assertRaisesRegexp(cppyy.gbl.runtime_error, "RDataFrame: empty list of input files."):
+                ROOT.RDataFrame("events", [])
+
+            with self.assertRaisesRegexp(cppyy.gbl.runtime_error, "RDataFrame: empty list of input files."):
+                ROOT.RDataFrame("events", ROOT.std.vector[ROOT.std.string]())
+
+            with self.assertRaisesRegexp(cppyy.gbl.runtime_error, "RDataFrame: empty list of input files."):
+                ROOT.RDataFrame("events", ())
+
+
+if __name__ == '__main__':
+    unittest.main()