diff --git a/tests/parser/test_selector_table.py b/tests/parser/test_selector_table.py
new file mode 100644
index 0000000000..da3ace75f4
--- /dev/null
+++ b/tests/parser/test_selector_table.py
@@ -0,0 +1,86 @@
+import hypothesis.strategies as st
+import pytest
+from hypothesis import given, settings
+
+import vyper.utils as utils
+from vyper.compiler.settings import OptimizationLevel
+
+
+@pytest.mark.parametrize("opt_level", list(OptimizationLevel))
+@pytest.mark.parametrize("calldatasize_encoding_bytes", [1, 2, 3])
+@settings(max_examples=25, deadline=None)
+@given(seed=st.integers(min_value=0, max_value=2**64 - 1))
+@pytest.mark.fuzzing
+def test_selector_table_fuzz(
+    calldatasize_encoding_bytes, seed, opt_level, w3, get_contract, assert_tx_failed, get_logs
+):
+    max_calldata_bytes = 2 ** (8 * calldatasize_encoding_bytes)
+
+    def abi_sig(calldata_words, i):
+        args = "" if not calldata_words else f"uint256[{calldata_words}]"
+        return f"foo{seed + i}({args})"
+
+    def generate_func_def(mutability, calldata_words, i):
+        args = "" if not calldata_words else f"uint256[{calldata_words}]"
+        return f"""
+@external
+{mutability}
+def foo{seed + i}({args}) -> uint256:
+    return {i}
+        """
+
+    @given(
+        methods=st.lists(
+            st.tuples(
+                st.sampled_from(["@pure", "@view", "@nonpayable", "@payable"]),
+                st.integers(min_value=0, max_value=max_calldata_bytes // 32),
+            ),
+            min_size=1,
+            max_size=100,
+        )
+    )
+    def _test(methods):
+        code = "\n".join(generate_func_def(m, s, i) for i, (m, s) in enumerate(methods))
+
+        default_function = """
+event Default:
+    pass
+
+@external
+def __default__():
+    log Default()
+        """
+        code = code + default_function
+
+        c = get_contract(code)
+
+        for i, (mutability, n_calldata_words) in enumerate(methods):
+            funcname = f"foo{seed + i}"
+            func = getattr(c, funcname)
+            assert func([1] * n_calldata_words) == i
+
+            if mutability == "@payable":
+                assert func([1] * n_calldata_words, transact={"value": 1}) == i
+            else:
+                assert_tx_failed(lambda: func([1] * n_calldata_words, transact={"value": 1}))
+
+            # now do calldatasize check
+            method_id = utils.method_id(abi_sig(n_calldata_words, i))
+            argsdata = b"\x00" * (n_calldata_words * 32)
+            calldata = (method_id + argsdata)[:-1]  # strip one byte
+            hexstr = calldata.hex()
+            if method_id.endswith(b"\x00"):
+                # hit default function
+
+                tx = w3.eth.send_transaction({"to": c.address, "data": hexstr})
+                logs = get_logs(tx, c, "Default")
+                assert len(logs) == 1
+
+            else:
+                assert_tx_failed(w3.eth.send_transaction({"to": c.address, "data": hexstr}))
+
+        # TODO:
+        # - test default function with 0 bytes
+        # - test default function with 0-3 bytes of calldata
+
+    _test()