Fix handling of empty opaque fields

ref #533
AdaCore · Jan 4, 2021 · 04bbb34 · 04bbb34
1 parent 5501894
commit 04bbb34
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diff --git a/rflx/pyrflx/typevalue.py b/rflx/pyrflx/typevalue.py
@@ -385,6 +385,10 @@ def value(self) -> bytes:
     def bitstring(self) -> Bitstring:
         self._raise_initialized()
         assert self._value is not None
+        size = self.size
+        assert isinstance(size, Number)
+        if size.value == 0:
+            return Bitstring("")
         return Bitstring(format(int.from_bytes(self._value, "big"), f"0{self.size}b"))
 
     @property

diff --git a/tests/unit/pyrflx_test.py b/tests/unit/pyrflx_test.py
@@ -330,6 +330,14 @@ def test_message_value_required_fields(tlv_message_value: MessageValue) -> None:
     assert tlv_message_value.required_fields == []
 
 
+def test_message_value_empty_opaque_field(tlv_message_value: MessageValue) -> None:
+    tlv_message_value.set("Tag", "Msg_Data")
+    tlv_message_value.set("Length", 0)
+    tlv_message_value.set("Value", b"")
+    assert tlv_message_value.valid_message
+    assert tlv_message_value.bytestring == b"\x40\x00"
+
+
 def test_message_value_field_eq() -> None:
     f1 = MessageValue.Field(OpaqueValue(Opaque()), "f1")
     assert f1 == MessageValue.Field(OpaqueValue(Opaque()), "f1")