add more robust fuzzing, better slice errors

tests/functional/builtins/codegen/test_slice.py

@@ -2,6 +2,8 @@
 import pytest
 from hypothesis import given, settings
 
+from vyper import ast as vy_ast
+from vyper.builtins import functions as vy_fn
 from vyper.compiler.settings import OptimizationLevel
 from vyper.exceptions import ArgumentException, TypeMismatch
 
@@ -473,3 +475,21 @@ def test_comptime(get_contract, code, result):
         assert ret.hex() == result
     else:
         assert ret == result
+
+
+error_slice = [
+    "slice(0x00, 0, 1)",
+    'slice("why hello! how are you?", 32, 1)',
+    'slice("why hello! how are you?", -1, 1)',
+    'slice("why hello! how are you?", 4, 0)',
+    'slice("why hello! how are you?", 0, 33)',
+    'slice("why hello! how are you?", 16, 17)',
+]
+
+
+@pytest.mark.parametrize("code", error_slice)
+def test_slice_error(code):
+    vyper_ast = vy_ast.parse_to_ast(code)
+    old_node = vyper_ast.body[0].value
+    with pytest.raises(ArgumentException):
+        vy_fn.DISPATCH_TABLE["slice"].evaluate(old_node)

tests/functional/builtins/folding/test_slice.py

@@ -1,3 +1,5 @@
+import string
+
 import pytest
 from hypothesis import given, settings
 from hypothesis import strategies as st
@@ -7,6 +9,10 @@
 from vyper.exceptions import ArgumentException
 
 
+def normalize_bytes(data):
+    return bytes(int.from_bytes(data, "big"))
+
+
 @pytest.mark.fuzzing
 @settings(max_examples=50)
 @given(
@@ -33,11 +39,7 @@ def foo(a: bytes32) -> Bytes[{le}]:
 
     s *= 2
     le *= 2
-    assert (
-        int.from_bytes(contract.foo(a), "big")
-        == int.from_bytes(new_node.value, "big")
-        == int(a[2:][s : (s + le)], 16)
-    )
+    assert normalize_bytes(contract.foo(a)) == new_node.value == bytes.fromhex(a[2:][s : (s + le)])
 
 
 @pytest.mark.fuzzing
@@ -61,3 +63,58 @@ def test_slice_bytesnot32(a, s, le):
     old_node = vyper_ast.body[0].value
     with pytest.raises(ArgumentException):
         vy_fn.DISPATCH_TABLE["slice"].evaluate(old_node)
+
+
+@pytest.mark.fuzzing
+@settings(max_examples=50)
+@given(
+    a=st.binary(min_size=1, max_size=100),
+    s=st.integers(min_value=0, max_value=99),
+    le=st.integers(min_value=1, max_value=100),
+)
+def test_slice_dynbytes(get_contract, a, s, le):
+    s = s % len(a)
+    le = min(len(a), len(a) - s, le)
+
+    source = f"""
+@external
+def foo(a: Bytes[100]) -> Bytes[{le}]:
+    return slice(a, {s}, {le})
+    """
+    contract = get_contract(source)
+
+    vyper_ast = vy_ast.parse_to_ast(f"slice({a}, {s}, {le})")
+    old_node = vyper_ast.body[0].value
+    new_node = vy_fn.DISPATCH_TABLE["slice"].evaluate(old_node)
+
+    assert contract.foo(a) == new_node.value == a[s : (s + le)]
+
+
+valid_char = [
+    char for char in string.printable if char not in (string.whitespace.replace(" ", "") + '"\\')
+]
+
+
+@pytest.mark.fuzzing
+@settings(max_examples=50)
+@given(
+    a=st.text(alphabet=valid_char, min_size=1, max_size=100),
+    s=st.integers(min_value=0, max_value=99),
+    le=st.integers(min_value=1, max_value=100),
+)
+def test_slice_string(get_contract, a, s, le):
+    s = s % len(a)
+    le = min(len(a), len(a) - s, le)
+
+    source = f"""
+@external
+def foo(a: String[100]) -> String[{le}]:
+    return slice(a, {s}, {le})
+    """
+    contract = get_contract(source)
+
+    vyper_ast = vy_ast.parse_to_ast(f'slice("{a}", {s}, {le})')
+    old_node = vyper_ast.body[0].value
+    new_node = vy_fn.DISPATCH_TABLE["slice"].evaluate(old_node)
+
+    assert contract.foo(a) == new_node.value == a[s : (s + le)]

vyper/builtins/functions.py

@@ -318,7 +318,6 @@ def evaluate(self, node):
             else:
                 length = len(lit.value) // 2 - 1
                 if length != 32:
-                    # raise UnfoldableNode
                     raise ArgumentException("Length can only be of 32", lit)
                 st_val *= 2
                 le_val *= 2