[Exp PyROOT] Test contains pythonisation for TObject

bindings/pyroot_experimental/PyROOT/test/CMakeLists.txt

@@ -2,6 +2,9 @@
 ROOT_ADD_PYUNITTEST(pyroot_pyz_pretty_printing pretty_printing.py)
 ROOT_ADD_PYUNITTEST(pyroot_pyz_array_interface array_interface.py)
 
+# TObject and subclasses pythonisations
+ROOT_ADD_PYUNITTEST(pyroot_pyz_tobject_contains tobject_contains.py)
+
 # TDirectory and subclasses pythonizations
 ROOT_ADD_PYUNITTEST(pyroot_pyz_tdirectory_attrsyntax tdirectory_attrsyntax.py)
 ROOT_ADD_PYUNITTEST(pyroot_pyz_tdirectoryfile_attrsyntax_get tdirectoryfile_attrsyntax_get.py)

bindings/pyroot_experimental/PyROOT/test/tobject_contains.py

+import unittest
+
+import ROOT
+from libcppyy import SetOwnership
+
+
+class TObjectContains(unittest.TestCase):
+    """
+    Test for the __contains__ pythonisation of TObject and subclasses.
+    Such pythonisation relies on TObject::FindObject, which is redefined
+    in some of its subclasses, such as TCollection.
+    Thanks to this pythonisation, we can use the syntax `obj in col`
+    to know if col contains obj.
+    """
+
+    num_elems = 3
+
+    # Helpers
+    def create_tlist(self):
+        l = ROOT.TList()
+        for _ in range(self.num_elems):
+            o = ROOT.TObject()
+            # Prevent immediate deletion of C++ TObjects
+            SetOwnership(o, False)
+            l.Add(o)
+
+        return l
+
+    # Tests
+    def test_contains(self):
+        l = self.create_tlist()
+
+        for elem in l:
+            self.assertTrue(elem in l)
+            # Make sure it does not work just because of __iter__
+            self.assertTrue(l.__contains__(elem))
+
+        o = ROOT.TObject()
+        self.assertFalse(o in l)
+        self.assertFalse(l.__contains__(o))
+
+
+if __name__ == '__main__':
+    unittest.main()