chore: introduce FileHandler

Author: Daniel Sanz

src/twyn/core/exceptions.py

@@ -13,3 +13,4 @@ class AllowlistPackageAlreadyExistsError(AllowlistError):
 
 class AllowlistPackageDoesNotExistError(AllowlistError):
     message = "Package '{}' is not present in the allowlist. Skipping."
+

src/twyn/dependency_parser/abstract_parser.py

@@ -1,43 +1,29 @@
 import logging
-import os
 from abc import ABC, abstractmethod
-from pathlib import Path
 
-from twyn.base.exceptions import TwynError
-from twyn.dependency_parser.exceptions import (
-    PathIsNotFileError,
-    PathNotFoundError,
-)
+from twyn.file_handler.file_handler import FileHandlerPathlib
 
 logger = logging.getLogger()
 
 
 class AbstractParser(ABC):
-    def __init__(self, file_path: str = "") -> None:
-        self.file_path = Path(os.path.abspath(os.path.join(os.getcwd(), file_path)))
+    """
+    Abstract class for file parsers.
 
-    def __str__(self):
+    Provides basic methods to deal with the dependecies file.
+    """
+
+    def __init__(self, file_path: str) -> None:
+        self.file_handler = FileHandlerPathlib(file_path=file_path)
+
+    def __str__(self) -> str:
         return self.__class__.__name__
 
     def _read(self) -> str:
-        content = self.file_path.read_text()
-        logger.debug("Successfully read content from local dependencies file")
-
-        return content
+        return self.file_handler.read()
 
     def file_exists(self) -> bool:
-        try:
-            self.raise_for_valid_file()
-        except TwynError:
-            return False
-        return True
-
-    def raise_for_valid_file(self) -> None:
-        if not self.file_path.exists():
-            raise PathNotFoundError
-
-        if not self.file_path.is_file():
-            raise PathIsNotFileError
+        return self.file_handler.file_exists()
 
     @abstractmethod
     def parse(self) -> set[str]:

src/twyn/dependency_parser/dependency_selector.py

@@ -56,6 +56,5 @@ def get_dependency_parser(self) -> AbstractParser:
 
         file_parser = dependency_file_parser()
         logger.debug(f"Assigned {file_parser} parser for local dependencies file.")
-        file_parser.raise_for_valid_file()
 
         return file_parser

src/twyn/dependency_parser/exceptions.py

@@ -1,19 +1,9 @@
 from twyn.base.exceptions import TwynError
 
 
-class PathIsNotFileError(TwynError):
-    message = "Specified dependencies path is not a file"
-
-
-class PathNotFoundError(TwynError, FileNotFoundError):
-    message = "Specified dependencies file path does not exist"
-
-
 class NoMatchingParserError(TwynError):
     message = "Could not assign a dependency file parser. Please specify it with --dependency-file"
 
 
 class MultipleParsersError(TwynError):
-    message = (
-        "Can't auto detect dependencies file to parse. More than one format was found."
-    )
+    message = "Can't auto detect dependencies file to parse. More than one format was found."

src/twyn/file_handler/exceptions.py

@@ -0,0 +1,9 @@
+from twyn.base.exceptions import TwynError
+
+
+class PathIsNotFileError(TwynError):
+    message = "Specified dependencies path is not a file"
+
+
+class PathNotFoundError(TwynError, FileNotFoundError):
+    message = "Specified dependencies file path does not exist"

src/twyn/file_handler/file_handler.py

@@ -0,0 +1,42 @@
+import logging
+import os
+from pathlib import Path
+from typing import Protocol
+
+from twyn.base.exceptions import TwynError
+from twyn.file_handler.exceptions import PathIsNotFileError, PathNotFoundError
+
+logger = logging.getLogger()
+
+
+class BaseFileHandler(Protocol):
+    def __init__(self, file_path: str) -> None: ...
+    def read(self) -> str: ...
+    def file_exists(self) -> bool: ...
+
+
+class FileHandlerPathlib(BaseFileHandler):
+    def __init__(self, file_path: str) -> None:
+        self.file_path = Path(os.path.abspath(os.path.join(os.getcwd(), file_path)))
+
+    def read(self) -> str:
+        self._raise_for_file_exists()
+
+        content = self.file_path.read_text()
+        logger.debug("Successfully read content from local dependencies file")
+
+        return content
+
+    def file_exists(self) -> bool:
+        try:
+            self._raise_for_file_exists()
+        except TwynError:
+            return False
+        return True
+
+    def _raise_for_file_exists(self) -> None:
+        if not self.file_path.exists():
+            raise PathNotFoundError
+
+        if not self.file_path.is_file():
+            raise PathIsNotFileError

tests/conftest.py

@@ -1,23 +1,24 @@
 import os
+from typing import Generator
 
 import pytest
 
 
 @pytest.fixture
-def requirements_txt_file(tmp_path):
+def requirements_txt_file(tmp_path) -> Generator[str, None, None]:
     requirements_txt_file = tmp_path / "requirements.txt"
     requirements_txt_file.write_text(
         """
         South==1.0.1 --hash=sha256:abcdefghijklmno
         pycrypto>=2.6
         """
     )
-    yield requirements_txt_file
+    yield str(requirements_txt_file)
     os.remove(requirements_txt_file)
 
 
 @pytest.fixture
-def poetry_lock_file_lt_1_5(tmp_path):
+def poetry_lock_file_lt_1_5(tmp_path) -> Generator[str, None, None]:
     """Poetry lock version < 1.5."""
     poetry_lock_file = tmp_path / "poetry.lock"
     poetry_lock_file.write_text(
@@ -61,12 +62,12 @@ def poetry_lock_file_lt_1_5(tmp_path):
             mccabe = []
         """
     )
-    yield poetry_lock_file
+    yield str(poetry_lock_file)
     os.remove(poetry_lock_file)
 
 
 @pytest.fixture
-def poetry_lock_file_ge_1_5(tmp_path):
+def poetry_lock_file_ge_1_5(tmp_path) -> Generator[str, None, None]:
     """Poetry lock version >= 1.5."""
     poetry_lock_file = tmp_path / "poetry.lock"
     poetry_lock_file.write_text(
@@ -107,12 +108,12 @@ def poetry_lock_file_ge_1_5(tmp_path):
             mccabe = []
         """
     )
-    yield poetry_lock_file
+    yield str(poetry_lock_file)
     os.remove(poetry_lock_file)
 
 
 @pytest.fixture
-def pyproject_toml_file(tmp_path):
+def pyproject_toml_file(tmp_path) -> Generator[str, None, None]:
     pyproject_toml = tmp_path / "pyproject.toml"
     pyproject_toml.write_text(
         """
@@ -136,5 +137,5 @@ def pyproject_toml_file(tmp_path):
 
     """
     )
-    yield pyproject_toml
+    yield str(pyproject_toml)
     os.remove(pyproject_toml)

tests/dependency_parser/test_dependency_parser.py

@@ -1,10 +1,9 @@
 from unittest.mock import patch
 
 import pytest
-from twyn.base.exceptions import TwynError
 from twyn.dependency_parser import PoetryLockParser, RequirementsTxtParser
 from twyn.dependency_parser.abstract_parser import AbstractParser
-from twyn.dependency_parser.exceptions import PathIsNotFileError, PathNotFoundError
+from twyn.file_handler.exceptions import PathIsNotFileError, PathNotFoundError
 
 
 class TestAbstractParser:
@@ -15,34 +14,26 @@ def parse(self) -> set[str]:
             self._read()
             return set()
 
-    @patch("twyn.dependency_parser.abstract_parser.AbstractParser.raise_for_valid_file")
-    def test_file_exists_success(self, _mock_raise_for_valid_file):
+    @patch("pathlib.Path.exists")
+    @patch("pathlib.Path.is_file")
+    def test_file_exists(self, _mock_exists, _mock_is_file):
+        _mock_exists.return_value = True
+        _mock_is_file.return_value = True
         parser = self.TemporaryParser("fake_path.txt")
         assert parser.file_exists() is True
 
-    @patch("twyn.dependency_parser.abstract_parser.AbstractParser.raise_for_valid_file")
-    def test_file_exists_fail(self, mock_raise_for_valid_file):
-        def raise_twyn_error():
-            raise TwynError
-
-        mock_raise_for_valid_file.side_effect = raise_twyn_error
-        parser = self.TemporaryParser("fake_path.txt")
-        assert parser.file_exists() is False
-
     @patch("pathlib.Path.exists")
     @patch("pathlib.Path.is_file")
     @pytest.mark.parametrize(
         "file_exists, is_file, exception",
         [[False, False, PathNotFoundError], [True, False, PathIsNotFileError]],
     )
-    def test_raise_for_valid_file(
-        self, mock_is_file, mock_exists, file_exists, is_file, exception
-    ):
+    def test_raise_for_valid_file(self, mock_is_file, mock_exists, file_exists, is_file, exception):
         mock_exists.return_value = file_exists
         mock_is_file.return_value = is_file
 
-        with pytest.raises(exception):
-            self.TemporaryParser("fake_path").raise_for_valid_file()
+        parser = self.TemporaryParser("fake_path.txt")
+        assert parser.file_exists() is False
 
 
 class TestRequirementsTxtParser:

tests/dependency_parser/test_dependency_selector.py

@@ -12,10 +12,7 @@
 class TestDependencySelector:
     @patch("twyn.dependency_parser.poetry_lock.PoetryLockParser.file_exists")
     @patch("twyn.dependency_parser.requirements_txt.RequirementsTxtParser.file_exists")
-    @patch("twyn.dependency_parser.abstract_parser.AbstractParser.raise_for_valid_file")
-    @patch(
-        "twyn.dependency_parser.dependency_selector.DependencySelector._raise_for_selected_parsers"
-    )
+    @patch("twyn.dependency_parser.dependency_selector.DependencySelector._raise_for_selected_parsers")
     @pytest.mark.parametrize(
         "file_name, requirements_exists, poetry_exists, parser_obj",
         [
@@ -35,7 +32,6 @@ class TestDependencySelector:
     def test_get_dependency_parser(
         self,
         _raise_for_selected_parsers,
-        _raise_for_valid_file,
         req_exists,
         poet_exists,
         file_name,
@@ -53,9 +49,7 @@ def test_get_dependency_parser(
         [(True, MultipleParsersError), (False, NoMatchingParserError)],
     )
     @patch("twyn.dependency_parser.abstract_parser.AbstractParser.file_exists")
-    def test_auto_detect_dependency_file_parser_exceptions(
-        self, file_exists, exists, exception
-    ):
+    def test_auto_detect_dependency_file_parser_exceptions(self, file_exists, exists, exception):
         file_exists.return_value = exists
         with pytest.raises(exception):
             DependencySelector().get_dependency_parser()

tests/file_handler/test_file_handler.py

@@ -0,0 +1,37 @@
+from unittest.mock import patch
+
+import pytest
+from twyn.file_handler.exceptions import PathIsNotFileError, PathNotFoundError
+from twyn.file_handler.file_handler import FileHandlerPathlib
+
+
+class TestFileHandlerPathlib:
+    def test_file_exists(self, pyproject_toml_file: str):
+        parser = FileHandlerPathlib(pyproject_toml_file)
+        assert parser.file_exists() is True
+
+    def test_read_file_success(self, pyproject_toml_file: str):
+        parser = FileHandlerPathlib(pyproject_toml_file)
+        read = parser.read()
+        assert len(read) > 1
+        assert isinstance(read, str)
+
+    def test_read_file_does_not_exist(
+        self,
+    ):
+        parser = FileHandlerPathlib("")
+        with pytest.raises(PathIsNotFileError):
+            parser.read()
+
+    @patch("pathlib.Path.exists")
+    @patch("pathlib.Path.is_file")
+    @pytest.mark.parametrize(
+        "file_exists, is_file, exception",
+        [[False, False, PathNotFoundError], [True, False, PathIsNotFileError]],
+    )
+    def test_raise_for_valid_file(self, mock_is_file, mock_exists, file_exists, is_file, exception):
+        mock_exists.return_value = file_exists
+        mock_is_file.return_value = is_file
+
+        parser = FileHandlerPathlib("fake.txt")
+        assert parser.file_exists() is False