Add test for non-string tag for TaggedOperation circuit diagrams (#2800)

cirq/ops/raw_types_test.py

@@ -460,8 +460,17 @@ def test_tagged_operation():
 
 
 def test_circuit_diagram():
+
+    class TaggyTag:
+        """Tag with a custom repr function to test circuit diagrams."""
+
+        def __repr__(self):
+            return 'TaggyTag()'
+
     h = cirq.H(cirq.GridQubit(1, 1))
     tagged_h = h.with_tags('tag1')
+    non_string_tag_h = h.with_tags(TaggyTag())
+
     expected = cirq.CircuitDiagramInfo(wire_symbols=("H['tag1']",),
                                        exponent=1.0,
                                        connected=True,
@@ -479,6 +488,11 @@ def test_circuit_diagram():
     assert c.to_text_diagram() == diagram_with_tags
     assert c.to_text_diagram(include_tags=False) == diagram_without_tags
 
+    c = cirq.Circuit(non_string_tag_h)
+    diagram_with_non_string_tag = "(1, 1): ───H[TaggyTag()]───"
+    assert c.to_text_diagram() == diagram_with_non_string_tag
+    assert c.to_text_diagram(include_tags=False) == diagram_without_tags
+
 
 def test_circuit_diagram_tagged_global_phase():
     # Tests global phase operation