diff --git a/src/sio3pack/__init__.py b/src/sio3pack/__init__.py
index 51fe899..9761228 100644
--- a/src/sio3pack/__init__.py
+++ b/src/sio3pack/__init__.py
@@ -1,10 +1,10 @@
 __version__ = "0.0.1"
 
-from sio3pack.files.file import File
+from sio3pack.files import LocalFile
 from sio3pack.packages.package import Package
 
 
-def from_file(file: str | File, django_settings=None) -> Package:
+def from_file(file: str | LocalFile, django_settings=None) -> Package:
     """
     Initialize a package object from a file (archive or directory).
     :param file: The file path or File object.
@@ -12,5 +12,5 @@ def from_file(file: str | File, django_settings=None) -> Package:
     :return: The package object.
     """
     if isinstance(file, str):
-        file = File(file)
-    return Package.from_file(file, django_settings)
+        file = LocalFile(file)
+    return Package.from_file(file, django_settings=django_settings)
diff --git a/src/sio3pack/files/__init__.py b/src/sio3pack/files/__init__.py
index bedfbe6..ca063b6 100644
--- a/src/sio3pack/files/__init__.py
+++ b/src/sio3pack/files/__init__.py
@@ -1,2 +1,3 @@
 from sio3pack.files.filetracker_file import FiletrackerFile
 from sio3pack.files.local_file import LocalFile
+from sio3pack.files.file import File
diff --git a/src/sio3pack/files/file.py b/src/sio3pack/files/file.py
index 779ec3a..1ae0908 100644
--- a/src/sio3pack/files/file.py
+++ b/src/sio3pack/files/file.py
@@ -1,36 +1,16 @@
-import os.path
-
-
 class File:
     """
     Base class for all files in a package.
     """
 
-    @classmethod
-    def get_file_matching_extension(cls, dir: str, filename: str, extensions: list[str]) -> "File":
-        """
-        Get the file with the given filename and one of the given extensions.
-        :param dir: The directory to search in.
-        :param filename: The filename.
-        :param extensions: The extensions.
-        :return: The file object.
-        """
-        for ext in extensions:
-            path = os.path.join(dir, filename + ext)
-            if os.path.exists(path):
-                return cls(path)
-        raise FileNotFoundError
-
     def __init__(self, path: str):
-        if not os.path.exists(path):
-            raise FileNotFoundError
         self.path = path
-        self.filename = os.path.basename(path)
+
+    def __str__(self):
+        return f"<{self.__class__.__name__} {self.path}>"
 
     def read(self) -> str:
-        with open(self.path, "r") as f:
-            return f.read()
+        raise NotImplementedError()
 
     def write(self, text: str):
-        with open(self.path, "w") as f:
-            f.write(text)
+        raise NotImplementedError()
diff --git a/src/sio3pack/files/filetracker_file.py b/src/sio3pack/files/filetracker_file.py
index 3698e2d..9ee022e 100644
--- a/src/sio3pack/files/filetracker_file.py
+++ b/src/sio3pack/files/filetracker_file.py
@@ -8,3 +8,5 @@ class FiletrackerFile(File):
 
     def __init__(self, path: str):
         super().__init__(path)
+        # TODO: should raise FileNotFoundError if file is not tracked
+        raise NotImplementedError()
diff --git a/src/sio3pack/files/local_file.py b/src/sio3pack/files/local_file.py
index 95f4009..43b1c15 100644
--- a/src/sio3pack/files/local_file.py
+++ b/src/sio3pack/files/local_file.py
@@ -1,3 +1,5 @@
+import os
+
 from sio3pack.files.file import File
 
 
@@ -6,5 +8,31 @@ class LocalFile(File):
     Base class for all files in a package that are stored locally.
     """
 
+    @classmethod
+    def get_file_matching_extension(cls, dir: str, filename: str, extensions: list[str]) -> "LocalFile":
+        """
+        Get the file with the given filename and one of the given extensions.
+        :param dir: The directory to search in.
+        :param filename: The filename.
+        :param extensions: The extensions.
+        :return: The file object.
+        """
+        for ext in extensions:
+            path = os.path.join(dir, filename + ext)
+            if os.path.exists(path):
+                return cls(path)
+        raise FileNotFoundError
+
     def __init__(self, path: str):
+        if not os.path.exists(path):
+            raise FileNotFoundError
         super().__init__(path)
+        self.filename = os.path.basename(path)
+
+    def read(self) -> str:
+        with open(self.path, "r") as f:
+            return f.read()
+
+    def write(self, text: str):
+        with open(self.path, "w") as f:
+            f.write(text)
diff --git a/src/sio3pack/graph/__init__.py b/src/sio3pack/graph/__init__.py
index bf9957e..79efe46 100644
--- a/src/sio3pack/graph/__init__.py
+++ b/src/sio3pack/graph/__init__.py
@@ -1 +1,3 @@
-from sio3pack.graph import Graph
+from sio3pack.graph.graph import Graph
+from sio3pack.graph.graph_manager import GraphManager
+from sio3pack.graph.graph_op import GraphOperation
diff --git a/src/sio3pack/graph/graph.py b/src/sio3pack/graph/graph.py
index cdd50b2..370cbb8 100644
--- a/src/sio3pack/graph/graph.py
+++ b/src/sio3pack/graph/graph.py
@@ -5,7 +5,7 @@ class Graph:
 
     @classmethod
     def from_dict(cls, data: dict):
-        raise NotImplemented
+        raise NotImplementedError()
 
     def __init__(self, name: str):
         self.name = name
@@ -14,4 +14,4 @@ def get_prog_files(self) -> list[str]:
         """
         Get all program files in the graph.
         """
-        raise NotImplemented
+        raise NotImplementedError()
diff --git a/src/sio3pack/graph/graph_manager.py b/src/sio3pack/graph/graph_manager.py
index 585ba8b..4a8e4f8 100644
--- a/src/sio3pack/graph/graph_manager.py
+++ b/src/sio3pack/graph/graph_manager.py
@@ -1,6 +1,6 @@
 import json
 
-from sio3pack import File
+from sio3pack.files import File
 from sio3pack.graph.graph import Graph
 
 
diff --git a/src/sio3pack/packages/exceptions.py b/src/sio3pack/packages/exceptions.py
index ca91db2..307b736 100644
--- a/src/sio3pack/packages/exceptions.py
+++ b/src/sio3pack/packages/exceptions.py
@@ -1,2 +1,4 @@
 class UnknownPackageType(Exception):
-    pass
+    def __init__(self, path: str) -> None:
+        self.path = path
+        super().__init__(f"Unknown package type for file {path}.")
diff --git a/src/sio3pack/packages/package/model.py b/src/sio3pack/packages/package/model.py
index 85972e1..0a863ec 100644
--- a/src/sio3pack/packages/package/model.py
+++ b/src/sio3pack/packages/package/model.py
@@ -1,9 +1,10 @@
 from typing import Any
 
-from sio3pack.files.file import File
-from sio3pack.graph.graph import Graph
+from sio3pack import LocalFile
+from sio3pack.files import File
+from sio3pack.graph import Graph
 from sio3pack.packages.exceptions import UnknownPackageType
-from sio3pack.test.test import Test
+from sio3pack.test import Test
 from sio3pack.utils.archive import Archive
 from sio3pack.utils.classinit import RegisteredSubclassesBase
 
@@ -18,17 +19,18 @@ class Package(RegisteredSubclassesBase):
     def __init__(self, file: File):
         super().__init__()
         self.file = file
-        if Archive.is_archive(file.path):
-            self.is_archive = True
-        else:
-            self.is_archive = False
+        if isinstance(file, LocalFile):
+            if Archive.is_archive(file.path):
+                self.is_archive = True
+            else:
+                self.is_archive = False
 
     @classmethod
-    def from_file(cls, file: File, django_settings=None):
+    def from_file(cls, file: LocalFile, django_settings=None):
         for subclass in cls.subclasses:
             if subclass.identify(file):
                 return subclass(file, django_settings)
-        raise UnknownPackageType
+        raise UnknownPackageType(file.path)
 
     def get_task_id(self) -> str:
         pass
diff --git a/src/sio3pack/packages/sinolpack/model.py b/src/sio3pack/packages/sinolpack/model.py
index 65fb3b8..09fbea4 100644
--- a/src/sio3pack/packages/sinolpack/model.py
+++ b/src/sio3pack/packages/sinolpack/model.py
@@ -4,10 +4,11 @@
 
 import yaml
 
-from sio3pack.files.file import File
-from sio3pack.graph.graph import Graph
-from sio3pack.graph.graph_manager import GraphManager
-from sio3pack.graph.graph_op import GraphOperation
+from sio3pack import LocalFile
+from sio3pack.files import File
+from sio3pack.graph import Graph
+from sio3pack.graph import GraphManager
+from sio3pack.graph import GraphOperation
 from sio3pack.packages.package import Package
 from sio3pack.packages.sinolpack.enums import ModelSolutionKind
 from sio3pack.util import naturalsort_key
@@ -37,7 +38,7 @@ def _find_main_dir(cls, archive: Archive) -> str | None:
         return None
 
     @classmethod
-    def identify(cls, file: File) -> bool:
+    def identify(cls, file: LocalFile) -> bool:
         """
         Identifies whether file is a Sinolpack.
 
@@ -57,21 +58,25 @@ def __del__(self):
 
     def __init__(self, file: File, django_settings=None):
         super().__init__(file)
-        if self.is_archive:
-            archive = Archive(file.path)
-            self.short_name = self._find_main_dir(archive)
-            self.tmpdir = tempfile.TemporaryDirectory()
-            archive.extract(to_path=self.tmpdir.name)
-            self.rootdir = os.path.join(self.tmpdir.name, self.short_name)
-        else:
-            self.short_name = os.path.basename(file.path)
-            self.rootdir = file.path
 
-        try:
-            graph_file = self.get_in_root("graph.json")
-            self.graph_manager = GraphManager.from_file(graph_file)
-        except FileNotFoundError:
-            self.has_custom_graph = False
+        if isinstance(file, LocalFile):
+            if self.is_archive:
+                archive = Archive(file.path)
+                self.short_name = self._find_main_dir(archive)
+                self.tmpdir = tempfile.TemporaryDirectory()
+                archive.extract(to_path=self.tmpdir.name)
+                self.rootdir = os.path.join(self.tmpdir.name, self.short_name)
+            else:
+                self.short_name = os.path.basename(file.path)
+                self.rootdir = file.path
+
+            try:
+                graph_file = self.get_in_root("graph.json")
+                self.graph_manager = GraphManager.from_file(graph_file)
+            except FileNotFoundError:
+                self.has_custom_graph = False
+        else:
+            raise NotImplementedError()
 
         self.django_settings = django_settings
 
@@ -98,17 +103,17 @@ def get_doc_dir(self) -> str:
         """
         return os.path.join(self.rootdir, "doc")
 
-    def get_in_doc_dir(self, filename: str) -> File:
+    def get_in_doc_dir(self, filename: str) -> LocalFile:
         """
         Returns the path to the input file in the documents' directory.
         """
-        return File(os.path.join(self.get_doc_dir(), filename))
+        return LocalFile(os.path.join(self.get_doc_dir(), filename))
 
-    def get_in_root(self, filename: str) -> File:
+    def get_in_root(self, filename: str) -> LocalFile:
         """
         Returns the path to the input file in the root directory.
         """
-        return File(os.path.join(self.rootdir, filename))
+        return LocalFile(os.path.join(self.rootdir, filename))
 
     def get_prog_dir(self) -> str:
         """
@@ -116,11 +121,11 @@ def get_prog_dir(self) -> str:
         """
         return os.path.join(self.rootdir, "prog")
 
-    def get_in_prog_dir(self, filename: str) -> File:
+    def get_in_prog_dir(self, filename: str) -> LocalFile:
         """
         Returns the path to the input file in the program directory.
         """
-        return File(os.path.join(self.get_prog_dir(), filename))
+        return LocalFile(os.path.join(self.get_prog_dir(), filename))
 
     def get_attachments_dir(self) -> str:
         """
@@ -247,7 +252,7 @@ def _process_prog_files(self):
             for file in ("ingen", "inwer", "soc", "chk"):
                 try:
                     self.additional_files.append(
-                        File.get_file_matching_extension(
+                        LocalFile.get_file_matching_extension(
                             self.get_prog_dir(), self.short_name + file, extensions
                         ).filename
                     )
diff --git a/src/sio3pack/test/__init__.py b/src/sio3pack/test/__init__.py
index 0478c51..9c36d80 100644
--- a/src/sio3pack/test/__init__.py
+++ b/src/sio3pack/test/__init__.py
@@ -1 +1 @@
-from sio3pack.test import Test
+from sio3pack.test.test import Test
diff --git a/src/sio3pack/test/simple_test.py b/src/sio3pack/test/simple_test.py
index 57c375c..3532aa0 100644
--- a/src/sio3pack/test/simple_test.py
+++ b/src/sio3pack/test/simple_test.py
@@ -1,5 +1,5 @@
-from sio3pack.files.file import File
-from sio3pack.test.test import Test
+from sio3pack.files import File
+from sio3pack.test import Test
 
 
 class SimpleTest(Test):
diff --git a/src/sio3pack/utils/archive.py b/src/sio3pack/utils/archive.py
index 847eb81..533dd1d 100644
--- a/src/sio3pack/utils/archive.py
+++ b/src/sio3pack/utils/archive.py
@@ -65,6 +65,9 @@ def __init__(self, file, ext=""):
         self.filename = file
         self._archive = self._archive_cls(self.filename, ext=ext)(self.filename)
 
+    def __str__(self):
+        return f'<Archive({self._archive.__class__.__name__}) {self.filename}>'
+
     @staticmethod
     def _archive_cls(file, ext=""):
         """
@@ -220,7 +223,13 @@ def filenames(self):
         return [zipinfo.filename for zipinfo in self._archive.infolist() if not zipinfo.is_dir()]
 
     def dirnames(self):
-        return [zipinfo.filename for zipinfo in self._archive.infolist() if zipinfo.is_dir()]
+        dirs = set()
+        for zipinfo in self._archive.infolist():
+            if zipinfo.is_dir():
+                dirs.add(zipinfo.filename)
+            else:
+                dirs.add(os.path.dirname(zipinfo.filename))
+        return list(dirs)
 
 
 extension_map = {
diff --git a/tests/fixtures.py b/tests/fixtures.py
index 7e31c57..1e2a433 100644
--- a/tests/fixtures.py
+++ b/tests/fixtures.py
@@ -19,6 +19,17 @@ class Compression(Enum):
 all_compressions = [c.value for c in Compression if c != Compression.NONE]
 
 
+class PackageInfo:
+    def __init__(self, path, type, task_id, compression):
+        self.path = path
+        self.type = type
+        self.task_id = task_id
+        self.compression = compression
+
+    def is_archive(self):
+        return self.compression != Compression.NONE
+
+
 def _tar_archive(dir, dest, compression=None):
     """
     Create a tar archive of the specified directory.
@@ -38,10 +49,12 @@ def _zip_archive(dir, dest):
     with zipfile.ZipFile(dest, "w") as zip:
         for root, dirs, files in os.walk(dir):
             for file in files:
-                zip.write(os.path.join(root, file), os.path.relpath(os.path.join(root, file), dir))
+                file_path = os.path.join(root, file)
+                arcname = os.path.join(os.path.basename(dir), os.path.relpath(file_path, dir))
+                zip.write(file_path, arcname)
 
 
-def _create_package(package_name, tmpdir, archive=False, extension="zip"):
+def _create_package(package_name, tmpdir, archive=False, extension=Compression.ZIP):
     packages = os.path.join(os.path.dirname(__file__), "test_packages")
     if not os.path.exists(os.path.join(packages, package_name)):
         raise FileNotFoundError(f"Package {package_name} does not exist")
@@ -58,43 +71,46 @@ def _create_package(package_name, tmpdir, archive=False, extension="zip"):
     os.unlink(os.path.join(package_path, "__init__.py"))
 
     if archive:
-        if extension == "zip":
+        if extension == Compression.ZIP:
             _zip_archive(package_path, os.path.join(tmpdir.name, f"{task_id}.zip"))
-        elif extension == "tar":
-            _tar_archive(package_path, os.path.join(tmpdir.name, f"{task_id}.tar"))
-        elif extension == "tar.gz" or extension == "tgz":
-            _tar_archive(package_path, os.path.join(tmpdir.name, f"{task_id}.{extension}"), "gz")
+        elif extension == Compression.TAR_GZ or extension == Compression.TGZ:
+            _tar_archive(package_path, os.path.join(tmpdir.name, f"{task_id}.{extension.value}"), "gz")
         else:
             raise ValueError(f"Unknown extension {extension}")
-        package_path = os.path.join(tmpdir.name, f"{task_id}.{extension}")
+        package_path = os.path.join(tmpdir.name, f"{task_id}.{extension.value}")
 
-    return package_path, type
+    return PackageInfo(
+        path=package_path,
+        type=type,
+        task_id=task_id,
+        compression=extension,
+    )
 
 
 @pytest.fixture
-def package(request):
+def get_package(request):
     """
     Fixture to create a temporary directory with specified package.
     """
     package_name = request.param
     tmpdir = tempfile.TemporaryDirectory()
-    package_path, type = _create_package(package_name, tmpdir)
+    package_info = _create_package(package_name, tmpdir)
 
-    yield package_path, type
+    yield lambda: package_info
 
     tmpdir.cleanup()
 
 
 @pytest.fixture
-def package_archived(request):
+def get_archived_package(request):
     """
     Fixture to create a temporary directory with specified package, but archived.
     """
     package_name, extension = request.param
     archive = extension != Compression.NONE
     tmpdir = tempfile.TemporaryDirectory()
-    package_path, type = _create_package(package_name, tmpdir, archive, extension)
+    package_info = _create_package(package_name, tmpdir, archive, extension)
 
-    yield package_path, type
+    yield lambda: package_info
 
     tmpdir.cleanup()
diff --git a/tests/packages/sinolpack/test_sinolpack.py b/tests/packages/sinolpack/test_sinolpack.py
index c591fad..d4a6d13 100644
--- a/tests/packages/sinolpack/test_sinolpack.py
+++ b/tests/packages/sinolpack/test_sinolpack.py
@@ -2,20 +2,19 @@
 
 import pytest
 
-from tests.fixtures import Compression, all_compressions, package, package_archived
+import sio3pack
+from sio3pack.packages import Sinolpack
+from tests.fixtures import Compression, all_compressions, get_package, get_archived_package, PackageInfo
 
 
-@pytest.mark.parametrize("package", ["simple"], indirect=True)
-def test_simple(package):
-    package_path, type = package
-    assert type == "sinolpack"
-    print(os.listdir(package_path))
-    assert os.path.isdir(package_path)
-
-
-@pytest.mark.parametrize("package_archived", [("simple", c) for c in all_compressions], indirect=True)
-def test_archive(package_archived):
-    package_path, type = package_archived
-    assert type == "sinolpack"
-    print(package_path)
-    assert os.path.isfile(package_path)
+@pytest.mark.parametrize("get_archived_package", [("simple", c) for c in Compression], indirect=True)
+def test_from_file(get_archived_package):
+    package_info: PackageInfo = get_archived_package()
+    assert package_info.type == "sinolpack"
+    package = sio3pack.from_file(package_info.path)
+    assert isinstance(package, Sinolpack)
+    assert package.short_name == package_info.task_id
+    if package_info.is_archive():
+        assert package.is_archive
+    else:
+        assert package.rootdir == package_info.path
diff --git a/tests/utils.py b/tests/utils.py
new file mode 100644
index 0000000..e69de29