Handle frozen variants explicitly

tests/test_misc.py

@@ -1731,7 +1731,7 @@ def test_compiler_options(self):
             p = parse(f.read())
         p1 = tools.compile(p, compiler_config.OPT_O0_CONFIG)
         p2 = tools.compile(p, compiler_config.OPT_O3_CONFIG)
-        self.assertNotEquals(
+        self.assertNotEqual(
             p1.dumps(), p2.dumps(), "Compiler options did not change the program."
         )
         for i in range(5):

tests/test_roundtrips.py

@@ -217,6 +217,10 @@ def visit_Variable(self, node: Variable):
 class HypothesisTests(unittest.TestCase):
     @hypothesis.given(uplc_program, hst.sampled_from(UPLCDialect))
     @hypothesis.settings(max_examples=1000, deadline=None)
+    @hypothesis.example(
+        Program(version=(1, 0, 0), term=PlutusMap(frozendict.frozendict({}))),
+        UPLCDialect.LegacyAiken,
+    )
     @hypothesis.example(
         Program(version=(1, 0, 0), term=BuiltinByteString(value=b"")),
         UPLCDialect.LegacyAiken,
@@ -452,6 +456,7 @@ def test_flat_unflat_roundtrip(self, p: Program):
     # TODO test invalid programs being detected with an free variable error
 
     @hypothesis.given(uplc_data)
+    @hypothesis.example(PlutusMap({}))
     def test_cbor_plutus_data_roundtrip(self, p: PlutusData):
         encoded = plutus_cbor_dumps(p)
         decoded = data_from_cbor(encoded)

uplc/ast.py

@@ -634,6 +634,12 @@ def default_encoder(encoder: CBOREncoder, value: Union[PlutusData, IndefiniteLis
             encoder.encode(item)
         encoder.write(b"\xff")
         return
+    if isinstance(value, frozendict.frozendict):
+        encoder.encode(dict(value))
+        return
+    if isinstance(value, frozenlist):
+        encoder.encode(list(value))
+        return
     if not isinstance(value, PlutusData):
         raise NotImplementedError(f"Can not encode type {type(value)}")
     value = value.to_cbor()