diff --git a/tests/test_basic_deflator.py b/tests/test_basic_deflator.py
new file mode 100644
index 0000000..a3cfb46
--- /dev/null
+++ b/tests/test_basic_deflator.py
@@ -0,0 +1,77 @@
+from __future__ import annotations
+from dataclasses import dataclass
+from typing import Optional
+
+from megasniff.deflator import SchemaDeflatorGenerator
+from src.megasniff import SchemaInflatorGenerator
+
+
+def test_basic_deflator():
+    class A:
+        a: int
+
+        def __init__(self, a: int):
+            self.a = a
+
+    class B:
+        def __init__(self, b: int):
+            self.b = b
+
+    defl = SchemaDeflatorGenerator()
+    fn = defl.schema_to_deflator(A)
+    a = fn(A(42))
+
+    assert a['a'] == 42
+
+    fnb = defl.schema_to_deflator(B)
+    b = fnb(B(11))
+    assert len(b) == 0
+
+
+def test_unions():
+    @dataclass
+    class A:
+        a: int | str
+
+    defl = SchemaDeflatorGenerator()
+    fn = defl.schema_to_deflator(A)
+
+    a = fn(A(42))
+    assert a['a'] == 42
+    a = fn(A('42'))
+    assert a['a'] == '42'
+    a = fn(A('42a'))
+    assert a['a'] == '42a'
+
+
+@dataclass
+class CircA:
+    b: CircB
+
+
+@dataclass
+class CircB:
+    a: CircA | None
+
+
+def test_circular():
+    defl = SchemaDeflatorGenerator()
+    fn = defl.schema_to_deflator(CircA)
+    a = fn(CircA(CircB(CircA(CircB(None)))))
+
+    assert isinstance(a['b'], dict)
+    assert isinstance(a['b']['a'], dict)
+    assert a['b']['a']['b']['a'] is None
+
+
+def test_optional():
+    @dataclass
+    class C:
+        a: Optional[int] = None
+
+    defl = SchemaDeflatorGenerator()
+    fn = defl.schema_to_deflator(C)
+    c = fn(C())
+    assert c['a'] is None
+    c = fn(C(123))
+    assert c['a'] == 123