Serve a download from the built book, and delete stale uploads

A download built the book again each time. It now sends the kept build,
and builds only if the book changed after it. Stop tracking deletes the
built book. A cancelled import deletes its uploaded file, and the start
deletes the uploads that no job needs.

tests/test_build_keys.py

@@ -203,3 +203,79 @@ def test_the_first_check_after_an_upgrade_sends_nothing(builds, monkeypatch):
     site(monkeypatch, ONE)
     assert update(story_id).startswith("No changes")
     assert builds.call_count == 0 and ingest_files() == []
+
+
+# Downloads in the browser
+
+
+def download(client, story_id):
+    response = client.get(f"/api/stories/{story_id}/epub")
+    assert response.status_code == 200 and response.data.startswith(b"PK")
+    assert response.content_length == len(response.data)
+    response.close()
+    return response.data
+
+
+def test_a_download_uses_the_built_book(builds, client, monkeypatch):
+    story_id = linked_story(ONE)
+    site(monkeypatch, ONE)
+    update(story_id)
+    (built,) = config.TMP_DIR.iterdir()
+    assert download(client, story_id) == download(client, story_id) == built.read_bytes()
+    assert builds.call_count == 1
+
+
+def test_a_download_builds_a_book_that_has_no_file_or_that_changed(builds, client, monkeypatch):
+    story_id = add_story()
+    first = download(client, story_id)
+    download(client, story_id)
+    assert builds.call_count == 1
+    orchestrator.save_rules(story_id, [{"pattern": "Zorian", "replacement": "Zach"}])
+    assert download(client, story_id) != first
+    assert builds.call_count == 2
+    assert len(list(config.TMP_DIR.iterdir())) == 1
+    # The build of a download is not the build of a job. The job sends the book, and marks the change.
+    assert orchestrator.store.get_setting(story_id, "built_key") is None
+    job = Job(mode=DownloadMode.REBUILD, story_id=story_id)
+    assert "library book 1" in orchestrator._run_rebuild(job)
+    assert builds.call_count == 2
+    assert story(story_id)["last_changed"]
+
+
+def test_stop_tracking_deletes_the_built_book(builds, client):
+    story_id, other = add_story(), orchestrator.store.create_story("https://other", "s", "Other", "W", [])
+    download(client, story_id)
+    kept = config.TMP_DIR / f"story-{other}-0123456789abcdef.epub"
+    kept.write_bytes(b"other")
+    orchestrator.delete_story(story_id)
+    assert list(config.TMP_DIR.iterdir()) == [kept]
+
+
+# Uploaded files
+
+
+@pytest.fixture
+def uploads(monkeypatch, tmp_path):
+    monkeypatch.setattr(config, "UPLOAD_DIR", tmp_path / "uploads")
+    config.UPLOAD_DIR.mkdir()
+    return config.UPLOAD_DIR
+
+
+def test_a_cancelled_import_deletes_its_uploaded_file(builds, jobs, uploads, story_epub):
+    path = uploads / "one.epub"
+    path.write_bytes(story_epub)
+    queued = orchestrator.queue_epub_file(path, "story.epub")
+    assert "path" not in queued["options"]
+    assert orchestrator.cancel_job(queued["id"]) is True
+    assert not path.exists()
+    assert orchestrator.cancel_job(queued["id"]) is False
+    assert orchestrator.cancel_job("no-such-job") is False
+
+
+def test_the_start_deletes_uploads_that_no_job_needs(builds, jobs, uploads, story_epub):
+    waiting, stale = uploads / "waiting.epub", uploads / "stale.epub"
+    for path in (waiting, stale):
+        path.write_bytes(story_epub)
+    orchestrator.queue_epub_file(waiting, "story.epub")
+    orchestrator.remove_stale_uploads()
+    assert list(uploads.iterdir()) == [waiting]