improved unit test case coverage for controller/common module

api/tests/unit_tests/controllers/common/test_errors.py

@@ -0,0 +1,70 @@
+from controllers.common.errors import (
+    BlockedFileExtensionError,
+    FilenameNotExistsError,
+    FileTooLargeError,
+    NoFileUploadedError,
+    RemoteFileUploadError,
+    TooManyFilesError,
+    UnsupportedFileTypeError,
+)
+
+
+class TestFilenameNotExistsError:
+    def test_defaults(self):
+        error = FilenameNotExistsError()
+
+        assert error.code == 400
+        assert error.description == "The specified filename does not exist."
+
+
+class TestRemoteFileUploadError:
+    def test_defaults(self):
+        error = RemoteFileUploadError()
+
+        assert error.code == 400
+        assert error.description == "Error uploading remote file."
+
+
+class TestFileTooLargeError:
+    def test_defaults(self):
+        error = FileTooLargeError()
+
+        assert error.code == 413
+        assert error.error_code == "file_too_large"
+        assert error.description == "File size exceeded. {message}"
+
+
+class TestUnsupportedFileTypeError:
+    def test_defaults(self):
+        error = UnsupportedFileTypeError()
+
+        assert error.code == 415
+        assert error.error_code == "unsupported_file_type"
+        assert error.description == "File type not allowed."
+
+
+class TestBlockedFileExtensionError:
+    def test_defaults(self):
+        error = BlockedFileExtensionError()
+
+        assert error.code == 400
+        assert error.error_code == "file_extension_blocked"
+        assert error.description == "The file extension is blocked for security reasons."
+
+
+class TestTooManyFilesError:
+    def test_defaults(self):
+        error = TooManyFilesError()
+
+        assert error.code == 400
+        assert error.error_code == "too_many_files"
+        assert error.description == "Only one file is allowed."
+
+
+class TestNoFileUploadedError:
+    def test_defaults(self):
+        error = NoFileUploadedError()
+
+        assert error.code == 400
+        assert error.error_code == "no_file_uploaded"
+        assert error.description == "Please upload your file."

api/tests/unit_tests/controllers/common/test_file_response.py

@@ -1,22 +1,96 @@
 from flask import Response
+import pytest
 
-from controllers.common.file_response import enforce_download_for_html, is_html_content
+from controllers.common.file_response import (
+    enforce_download_for_html,
+    is_html_content,
+    _normalize_mime_type,
+)
 
 
-class TestFileResponseHelpers:
-    def test_is_html_content_detects_mime_type(self):
+class TestNormalizeMimeType:
+    def test_returns_empty_string_for_none(self):
+        assert _normalize_mime_type(None) == ""
+
+    def test_returns_empty_string_for_empty_string(self):
+        assert _normalize_mime_type("") == ""
+
+    def test_normalizes_mime_type(self):
+        assert _normalize_mime_type("Text/HTML; Charset=UTF-8") == "text/html"
+
+
+class TestIsHtmlContent:
+    def test_detects_html_via_mime_type(self):
         mime_type = "text/html; charset=UTF-8"
 
-        result = is_html_content(mime_type, filename="file.txt", extension="txt")
+        result = is_html_content(
+            mime_type=mime_type,
+            filename="file.txt",
+            extension="txt",
+        )
 
         assert result is True
 
-    def test_is_html_content_detects_extension(self):
-        result = is_html_content("text/plain", filename="report.html", extension=None)
+    def test_detects_html_via_extension_argument(self):
+        result = is_html_content(
+            mime_type="text/plain",
+            filename=None,
+            extension="html",
+        )
 
         assert result is True
 
-    def test_enforce_download_for_html_sets_headers(self):
+    def test_detects_html_via_filename_extension(self):
+        result = is_html_content(
+            mime_type="text/plain",
+            filename="report.html",
+            extension=None,
+        )
+
+        assert result is True
+
+    def test_returns_false_when_no_html_detected_anywhere(self):
+        """
+        Missing negative test:
+        - MIME type is not HTML
+        - filename has no HTML extension
+        - extension argument is not HTML
+        """
+        result = is_html_content(
+            mime_type="application/json",
+            filename="data.json",
+            extension="json",
+        )
+
+        assert result is False
+
+    def test_returns_false_when_all_inputs_are_none(self):
+        result = is_html_content(
+            mime_type=None,
+            filename=None,
+            extension=None,
+        )
+
+        assert result is False
+
+
+class TestEnforceDownloadForHtml:
+    def test_sets_attachment_when_filename_missing(self):
+        response = Response("payload", mimetype="text/html")
+
+        updated = enforce_download_for_html(
+            response,
+            mime_type="text/html",
+            filename=None,
+            extension="html",
+        )
+
+        assert updated is True
+        assert response.headers["Content-Disposition"] == "attachment"
+        assert response.headers["Content-Type"] == "application/octet-stream"
+        assert response.headers["X-Content-Type-Options"] == "nosniff"
+
+    def test_sets_headers_when_filename_present(self):
         response = Response("payload", mimetype="text/html")
 
         updated = enforce_download_for_html(
@@ -27,11 +101,12 @@ def test_enforce_download_for_html_sets_headers(self):
         )
 
         assert updated is True
-        assert "attachment" in response.headers["Content-Disposition"]
+        assert response.headers["Content-Disposition"].startswith("attachment")
+        assert "unsafe.html" in response.headers["Content-Disposition"]
         assert response.headers["Content-Type"] == "application/octet-stream"
         assert response.headers["X-Content-Type-Options"] == "nosniff"
 
-    def test_enforce_download_for_html_no_change_for_non_html(self):
+    def test_does_not_modify_response_for_non_html_content(self):
         response = Response("payload", mimetype="text/plain")
 
         updated = enforce_download_for_html(

api/tests/unit_tests/controllers/common/test_helpers.py

@@ -0,0 +1,174 @@
+import importlib
+import sys
+from uuid import UUID
+
+import httpx
+import pytest
+
+from controllers.common import helpers
+from controllers.common.helpers import FileInfo, guess_file_info_from_response
+
+
+def make_response(
+    url="https://example.com/file.txt",
+    headers=None,
+    content=None,
+):
+    return httpx.Response(
+        200,
+        request=httpx.Request("GET", url),
+        headers=headers or {},
+        content=content or b"",
+    )
+
+
+class TestGuessFileInfoFromResponse:
+    def test_filename_from_url(self):
+        response = make_response(
+            url="https://example.com/test.pdf",
+            content=b"Hello World",
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.filename == "test.pdf"
+        assert info.extension == ".pdf"
+        assert info.mimetype == "application/pdf"
+
+    def test_filename_from_content_disposition(self):
+        headers = {
+            "Content-Disposition": 'attachment; filename=myfile.csv',
+            "Content-Type": "text/csv",
+        }
+        response = make_response(
+            url="https://example.com/",
+            headers=headers,
+            content=b"Hello World",
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.filename == "myfile.csv"
+        assert info.extension == ".csv"
+        assert info.mimetype == "text/csv"
+
+    @pytest.mark.parametrize(
+        ("magic_available", "expected_ext"),
+        [
+            (True, "txt"),
+            (False, "bin"),
+        ],
+    )
+    def test_generated_filename_when_missing(self, monkeypatch, magic_available, expected_ext):
+        if magic_available:
+            if helpers.magic is None:
+                pytest.skip("python-magic is not installed, cannot run 'magic_available=True' test variant")
+        else:
+            monkeypatch.setattr(helpers, "magic", None)
+
+        response = make_response(
+            url="https://example.com/",
+            content=b"Hello World",
+        )
+
+        info = guess_file_info_from_response(response)
+
+        name, ext = info.filename.split(".")
+        UUID(name)
+        assert ext == expected_ext
+
+    def test_mimetype_from_header_when_unknown(self):
+        headers = {"Content-Type": "application/json"}
+        response = make_response(
+            url="https://example.com/file.unknown",
+            headers=headers,
+            content=b'{"a": 1}',
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.mimetype == "application/json"
+
+    def test_extension_added_when_missing(self):
+        headers = {"Content-Type": "image/png"}
+        response = make_response(
+            url="https://example.com/image",
+            headers=headers,
+            content=b"fakepngdata",
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.extension == ".png"
+        assert info.filename.endswith(".png")
+
+    def test_content_length_used_as_size(self):
+        headers = {
+            "Content-Length": "1234",
+            "Content-Type": "text/plain",
+        }
+        response = make_response(
+            url="https://example.com/a.txt",
+            headers=headers,
+            content=b"a" * 1234,
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.size == 1234
+
+    def test_size_minus_one_when_header_missing(self):
+        response = make_response(url="https://example.com/a.txt")
+
+        info = guess_file_info_from_response(response)
+
+        assert info.size == -1
+
+    def test_fallback_to_bin_extension(self):
+        headers = {"Content-Type": "application/octet-stream"}
+        response = make_response(
+            url="https://example.com/download",
+            headers=headers,
+            content=b"\x00\x01\x02\x03",
+        )
+
+        info = guess_file_info_from_response(response)
+
+        assert info.extension == ".bin"
+        assert info.filename.endswith(".bin")
+
+    def test_return_type(self):
+        response = make_response()
+
+        info = guess_file_info_from_response(response)
+
+        assert isinstance(info, FileInfo)
+
+
+class TestMagicImportWarnings:
+    @pytest.mark.parametrize(
+        ("platform_name", "expected_message"),
+        [
+            ("Windows", "pip install python-magic-bin"),
+            ("Darwin", "brew install libmagic"),
+            ("Linux", "sudo apt-get install libmagic1"),
+            ("Other", "install `libmagic`"),
+        ],
+    )
+    def test_magic_import_warning_per_platform(
+        self,
+        monkeypatch,
+        platform_name,
+        expected_message,
+    ):
+        sys.modules.pop("magic", None)
+
+        monkeypatch.setitem(sys.modules, "magic", None)
+
+        monkeypatch.setattr(helpers.platform, "system", lambda: platform_name)
+
+        with pytest.warns(UserWarning, match="To use python-magic") as warning:
+            importlib.reload(helpers)
+
+        assert expected_message in str(warning[0].message)
+        assert helpers.magic is None