Feature: add ExportSink ABC and DirectoryExportSink

src/documents/tests/export/test_sinks.py

@@ -1,6 +1,11 @@
 import io
 import json
+import os
+from pathlib import Path
 
+import pytest
+
+from documents.export.sinks import DirectoryExportSink
 from documents.export.sinks import StreamingManifestWriter
 from documents.export.sinks import _dumps
 
@@ -27,3 +32,139 @@ class TestStreamingManifestWriter:
         writer: StreamingManifestWriter = StreamingManifestWriter(handle)
         writer.close()
         assert json.loads(handle.getvalue()) == []
+
+
+class TestDirectoryExportSink:
+    @pytest.fixture()
+    def source_file(self, tmp_path: Path) -> Path:
+        src: Path = tmp_path / "src" / "doc.pdf"
+        src.parent.mkdir(parents=True)
+        src.write_bytes(b"PDF-CONTENT")
+        return src
+
+    def test_add_file_copies_to_relative_arcname(
+        self,
+        tmp_path: Path,
+        source_file: Path,
+    ) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            sink.add_file(source_file, "originals/doc.pdf")
+        assert (target / "originals" / "doc.pdf").read_bytes() == b"PDF-CONTENT"
+
+    def test_add_json_writes_file(self, tmp_path: Path) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            sink.add_json({"version": "x"}, "metadata.json")
+        assert json.loads((target / "metadata.json").read_text()) == {"version": "x"}
+
+    def test_stream_writes_manifest(self, tmp_path: Path) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            with sink.stream("manifest.json") as handle:
+                writer: StreamingManifestWriter = StreamingManifestWriter(handle)
+                writer.write_record({"pk": 1})
+                writer.close()
+        assert json.loads((target / "manifest.json").read_text()) == [{"pk": 1}]
+
+    def test_add_file_skips_when_size_and_mtime_match(
+        self,
+        tmp_path: Path,
+        source_file: Path,
+    ) -> None:
+        # Pre-existing target with identical size+mtime but DIFFERENT content:
+        # if add_file skips (no compare-checksums), the old content survives.
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        existing: Path = target / "originals" / "doc.pdf"
+        existing.parent.mkdir(parents=True)
+        # Same byte length as the source but different content + matching mtime,
+        # so a size/mtime comparison treats it as unchanged and skips the copy.
+        existing.write_bytes(b"X" * len(b"PDF-CONTENT"))
+        stat = source_file.stat()
+        os.utime(existing, (stat.st_atime, stat.st_mtime))
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            sink.add_file(source_file, "originals/doc.pdf", checksum="abc")
+        assert existing.read_bytes() == b"X" * len(b"PDF-CONTENT")  # skipped
+
+    def test_add_file_recopies_when_compare_checksums_differ(
+        self,
+        tmp_path: Path,
+        source_file: Path,
+    ) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        existing: Path = target / "originals" / "doc.pdf"
+        existing.parent.mkdir(parents=True)
+        existing.write_bytes(b"X" * len(b"PDF-CONTENT"))
+        stat = source_file.stat()
+        os.utime(existing, (stat.st_atime, stat.st_mtime))
+        with DirectoryExportSink(
+            target,
+            compare_checksums=True,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            # wrong checksum forces recopy despite matching size/mtime
+            sink.add_file(source_file, "originals/doc.pdf", checksum="not-the-real-sum")
+        assert existing.read_bytes() == b"PDF-CONTENT"  # recopied
+
+    def test_delete_prunes_unwritten_snapshot_files(
+        self,
+        tmp_path: Path,
+        source_file: Path,
+    ) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        stale: Path = target / "stale.pdf"
+        stale.write_bytes(b"STALE")
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=True,
+        ) as sink:
+            sink.add_file(source_file, "originals/doc.pdf")
+        assert not stale.exists()
+        assert (target / "originals" / "doc.pdf").exists()
+
+    def test_no_delete_keeps_unwritten_files(
+        self,
+        tmp_path: Path,
+        source_file: Path,
+    ) -> None:
+        target: Path = tmp_path / "out"
+        target.mkdir()
+        stale: Path = target / "stale.pdf"
+        stale.write_bytes(b"STALE")
+        with DirectoryExportSink(
+            target,
+            compare_checksums=False,
+            compare_json=False,
+            delete=False,
+        ) as sink:
+            sink.add_file(source_file, "originals/doc.pdf")
+        assert stale.exists()