- added tests "test_tstruct_default_field" and "test_tstruct_const_field"

- added setattrs

construct_typed/__init__.py

@@ -1,3 +1,11 @@
+from .generic_wrapper import (
+    Construct,
+    Adapter,
+    ListContainer,
+    Context,
+    ConstantOrContextLambda,
+    PathType,
+)
 from .tarray import TArray
 from .tenum import TEnum
 from .tstruct import TStruct, TBitStruct, TStructField
@@ -10,5 +18,11 @@ __all__ = [
     "TEnum",
     "TUnionField",
     "TUnion",
-    "TArray"
+    "TArray",
+    "Construct",
+    "Adapter",
+    "ListContainer",
+    "Context",
+    "ConstantOrContextLambda",
+    "PathType",
 ]

construct_typed/tstruct.py

@@ -21,16 +21,9 @@ def TStructField(
         subcon = cs.Renamed(subcon, newdocs=doc, newparsed=parsed)
 
     if subcon.flagbuildnone is True:
-        # some subcons have a predefined default value. all other have "None"
-        default: t.Any = None
-        if isinstance(subcon, (cs.Const, cs.Default)):
-            if callable(subcon.value):  # type: ignore
-                raise ValueError("lamda as default is not supported")
-            default = subcon.value  # type: ignore
-
         # if subcon builds from "None", set default to "None"
         field = dataclasses.field(
-            default=default,
+            default=None,
             init=False,
             metadata={"subcon": cs.Renamed(subcon, newdocs=doc)},
         )

tests/declarativeunittest.py

@@ -1,4 +1,5 @@
 import pytest
+
 xfail = pytest.mark.xfail
 skip = pytest.mark.skip
 skipif = pytest.mark.skipif
@@ -8,16 +9,18 @@ import os, math, random, collections, itertools, io, hashlib, binascii
 from construct import *
 from construct.lib import *
 
+
 class ZeroIO(io.BufferedIOBase):
-    def read(self, __size = None):
+    def read(self, __size=None):
         if __size is not None:
             return bytes(__size)
         else:
             return bytes(0)
 
-    def read1(self, __size = 0):
+    def read1(self, __size=0):
         return bytes(__size)
 
+
 ident = lambda x: x
 devzero = ZeroIO()
 
@@ -46,20 +49,26 @@ def common(format, datasample, objsample, sizesample=SizeofError, **kw):
         assert size == sizesample
 
 
+def setattrs(obj, **kwargs):
+    for name, value in kwargs.items():
+        setattr(obj, name, value)
+    return obj
+
+
 def commonhex(format, hexdata):
     commonbytes(format, binascii.unhexlify(hexdata))
 
 
 def commondumpdeprecated(format, filename):
     filename = "tests/deprecated_gallery/blobs/" + filename
-    with open(filename,'rb') as f:
+    with open(filename, "rb") as f:
         data = f.read()
     commonbytes(format, data)
 
 
 def commondump(format, filename):
     filename = "tests/gallery/blobs/" + filename
-    with open(filename,'rb') as f:
+    with open(filename, "rb") as f:
         data = f.read()
     commonbytes(format, data)
 

tests/declarativeunittest.pyi

@@ -6,6 +6,7 @@ import construct_typed as cst
 Buffer = t.Union[bytes, memoryview, bytearray]
 ParsedType = t.TypeVar("ParsedType")
 BuildTypes = t.TypeVar("BuildTypes")
+T = t.TypeVar("T")
 
 IdentType = t.TypeVar("IdentType")
 
@@ -32,6 +33,7 @@ def common(
     sizesample: t.Union[int, t.Type[Exception]] = ...,
     **kw: t.Any
 ) -> None: ...
+def setattrs(obj: T, **kwargs: t.Any) -> T: ...
 def commonhex(format: Construct[ParsedType, BuildTypes], hexdata: str) -> None: ...
 def commondumpdeprecated(
     format: Construct[ParsedType, BuildTypes], filename: str

tests/test_typed.py

@@ -3,11 +3,12 @@
 import enum
 import dataclasses
 import typing as t
-from .declarativeunittest import common, raises
+from .declarativeunittest import common, raises, setattrs
 import construct as cs
 import construct_typed as cst
 
-def test_tstruct_1() -> None:
+
+def test_tstruct() -> None:
     @dataclasses.dataclass
     class TestDataclass:
         a: int = cst.TStructField(cs.Int16ub)
@@ -50,6 +51,47 @@ def test_tstruct_nested() -> None:
     )
 
 
+def test_tstruct_default_field() -> None:
+    @dataclasses.dataclass
+    class Image:
+        width: int = cst.TStructField(cs.Int8ub)
+        height: int = cst.TStructField(cs.Int8ub)
+        pixels: t.Optional[bytes] = cst.TStructField(
+            cs.Default(
+                cs.Bytes(cs.this.width * cs.this.height),
+                lambda ctx: bytes(ctx.width * ctx.height),
+            )
+        )
+
+    common(
+        cst.TStruct(Image),
+        b"\x02\x03\x00\x00\x00\x00\x00\x00",
+        setattrs(Image(2, 3), pixels=bytes(6)),
+        sample_building=Image(2, 3),
+    )
+
+
+def test_tstruct_const_field() -> None:
+    @dataclasses.dataclass
+    class TestDataclass:
+        const_field: t.Optional[bytes] = cst.TStructField(cs.Const(b"\x00"))
+
+    common(
+        cst.TStruct(TestDataclass),
+        bytes(1),
+        setattrs(TestDataclass(), const_field=b"\x00"),
+        1,
+    )
+
+    assert (
+        raises(
+            cst.TStruct(TestDataclass).build,
+            setattrs(TestDataclass(), const_field=b"\x01"),
+        )
+        == cs.ConstError
+    )
+
+
 def test_tstruct_anonymus_fields_1() -> None:
     @dataclasses.dataclass
     class TestDataclass:
@@ -61,7 +103,7 @@ def test_tstruct_anonymus_fields_1() -> None:
     common(
         cst.TStruct(TestDataclass),
         bytes(2),
-        TestDataclass(),
+        setattrs(TestDataclass(), _1=b"\x00"),
         cs.SizeofError,
     )
 
@@ -97,7 +139,10 @@ def test_tstruct_wrong_dataclass() -> None:
         a: int = cst.TStructField(cs.Int16ub)
         b: int = cst.TStructField(cs.Int8ub)
 
-    assert raises(cst.TStruct(TestDataclass1).build, TestDataclass2(a=1, b=2)) == TypeError
+    assert (
+        raises(cst.TStruct(TestDataclass1).build, TestDataclass2(a=1, b=2)) == TypeError
+    )
+
 
 def test_tbitstruct() -> None:
     assert False