"""U3 — the declared embed seam, in a real DOM. The Python suite can prove what the server OFFERS. It cannot prove where a fragment lands, whether the author's own markup survived the mount, or whether four radio groups scattered down a report still submit as one POST — and that last one is the operator's most important workflow. Before U3 those properties were true by construction, because the server did the placing and the `form=` bindings were static by the time the page was parsed. Now they are true because `/_booth/embed.js` does it in a live document, which is a different kind of claim and needs a different kind of test. So: a real uvicorn on an ephemeral port, a real Chromium. SKIPS, NEVER FAILS, when playwright or the shared browser is unavailable. The box-wide store at /opt/ms-playwright pins specific Chromium revisions and a playwright release that wants a newer one dies with an opaque "Executable doesn't exist" — see pyproject's version bound. A test layer that goes red for an environment reason teaches nothing and trains people to ignore it. """ import json import socket import threading import time import pytest from booth.app import create_app playwright_api = pytest.importorskip( "playwright.sync_api", reason="playwright is not installed" ) @pytest.fixture(scope="module") def browser(): with playwright_api.sync_playwright() as pw: try: b = pw.chromium.launch() except Exception as exc: # noqa: BLE001 - any launch failure is a skip pytest.skip(f"no usable chromium: {exc}") yield b b.close() @pytest.fixture def live(tmp_path): """A real server, because a browser cannot talk to a TestClient.""" import uvicorn sock = socket.socket() sock.bind(("127.0.0.1", 0)) port = sock.getsockname()[1] sock.close() app = create_app(tmp_path, ttl_hours=24, start_sweeper=False) config = uvicorn.Config(app, host="127.0.0.1", port=port, log_level="error") server = uvicorn.Server(config) thread = threading.Thread(target=server.run, daemon=True) thread.start() deadline = time.time() + 10 while not server.started and time.time() < deadline: time.sleep(0.02) if not server.started: pytest.skip("uvicorn did not come up") try: yield f"http://127.0.0.1:{port}", tmp_path finally: server.should_exit = True thread.join(timeout=10) SEAM = '' def _multi(booth): from booth.marks import declare_pick booth.mkdir(parents=True, exist_ok=True) declare_pick(booth, "batch", {"title": "Round one", "questions": [ {"key": "r1", "prompt": "First?", "options": ["keep", "cut"]}, {"key": "r2", "prompt": "Second?", "options": ["keep", "cut"]}, ]}) return booth def _single(booth): from booth.marks import declare_pick booth.mkdir(parents=True, exist_ok=True) declare_pick(booth, "winner", {"prompt": "Which render wins?", "options": ["A — baseline", "B — async"]}) return booth def _open(browser, base, name, html, booth): (booth / "index.html").write_text(html, encoding="utf-8") page = browser.new_page() page.goto(f"{base}/b/{name}/", wait_until="networkidle") return page def _answer(booth): raw = json.loads((booth / ".marks.json").read_text()) return raw["marks"][0].get("answer") # ---- the chrome -------------------------------------------------------------- def test_a_declaring_page_gets_its_chrome_mounted(browser, live): base, data = live b = _single(data / "b") page = _open(browser, base, "b", f"r

R

{SEAM}", b) page.wait_for_selector(".booth-nav-home") assert page.locator("h1").inner_text() == "R" # the report is intact assert page.locator(".booth-nav-home").get_attribute("href").endswith("/") # the favicon question, asked of a parsed document instead of raw text assert page.locator('link[rel="icon"]').count() == 1 page.close() def test_a_page_that_never_declared_the_seam_still_mounts(browser, live): """The appended path: every verbatim booth that predates U3 keeps working without its author touching it.""" base, data = live b = _single(data / "b") page = _open(browser, base, "b", "

OLD

", b) page.wait_for_selector(".bk-ask") assert page.locator("h1").inner_text() == "OLD" assert page.locator(".booth-nav-home").count() == 1 page.close() def test_a_page_that_declares_its_own_icon_keeps_it(browser, live): base, data = live b = _single(data / "b") page = _open( browser, base, "b", f'' f"x{SEAM}", b) page.wait_for_selector(".booth-nav-home") icons = page.locator('link[rel="icon"]') assert icons.count() == 1 assert icons.get_attribute("href").startswith("data:image/png") page.close() # ---- placement --------------------------------------------------------------- REPORT = f"""audition

Three voices

{SEAM} """ def test_each_question_lands_where_the_author_put_it(browser, live): """The 2026-09-09 ruling, enforced in the DOM: the question for a voice sits under that voice, not on another page and not in a pile at the end. Both attribute spellings, because live reports use the older one.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", REPORT, b) page.wait_for_selector("#lawson .bk-ask") assert page.locator('#lawson input[name="choice.r1"]').count() == 2 assert page.locator('#jo input[name="choice.r2"]').count() == 2 # nothing spilled to the end of the body: every piece had an anchor assert page.locator("body > .bk-ask").count() == 0 assert page.locator("form#bk-ask-form-batch").count() == 1 page.close() def test_the_authors_wrapper_and_its_contents_survive_the_mount(browser, live): """The live `dfa-concepts` shape — a non-empty styled wrapper carrying the anchor attribute. The regex this replaced matched the opening tag and SUBSTITUTED it, eating the class and orphaning the heading. beforeend keeps both and puts the radios under the heading, which is what the markup says.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", ( '
' f"

The one asset that must survive

{SEAM}"), b) page.wait_for_selector(".ask .bk-ask") assert page.locator("div.ask").count() == 1 # class kept assert page.locator(".ask h3").inner_text() == "The one asset that must survive" assert page.locator('.ask input[name="choice.r1"]').count() == 2 # radios inside page.close() def test_an_unplaced_question_is_appended_and_so_is_its_submit(browser, live): """INV-7. A multi-question pick needs EVERY question on submit or the POST is unanswerable: a question that never reaches the page cannot be picked, and a submission with nothing picked at all is refused outright.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", f'
{SEAM}', b) # attached, not visible: the shared
is deliberately empty and so has # no box — the controls that bind to it are what the operator sees. page.wait_for_selector("form#bk-ask-form-batch", state="attached") # BOTH halves. Asserting only the appended r2 let a mutation that silently # swallowed the anchored r1 — while still recording it as placed — pass. assert page.locator('input[name="choice.r1"]').count() == 2 # anchored, mounted assert page.locator('input[name="choice.r2"]').count() == 2 # unplaced, appended assert page.locator("form#bk-ask-form-batch").count() == 1 # submittable page.close() def test_a_page_with_no_anchors_gets_the_whole_ask(browser, live): base, data = live b = _multi(data / "b") page = _open(browser, base, "b", f"

x

{SEAM}", b) page.wait_for_selector(".bk-ask") assert page.locator('input[name="choice.r1"]').count() == 2 assert page.locator('input[name="choice.r2"]').count() == 2 page.close() def test_an_anchor_naming_no_mark_is_left_alone(browser, live): """A typo'd id stays visible as the author's own empty element rather than being blanked — and the real ask is still never lost.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", f'
{SEAM}', b) page.wait_for_selector(".bk-ask") assert page.locator("#t").inner_html().strip() == "" assert page.locator('input[name="choice.r1"]').count() == 2 page.close() def test_the_tail_follows_payload_order(browser, live): """INV-6. Creation order and alphabetical order DISAGREE here on purpose: `winner` is created first, `batch` second, so payload order is winner-then-batch while an id sort would give the reverse. The first version of this fixture made the two identical, so sorting the tail alphabetically in JavaScript passed it — caught by a panel reading the fixture.""" base, data = live b = _single(data / "b") _multi(b) raw = json.loads((b / ".marks.json").read_text()) stamps = {"winner": "2026-09-22T10:00:00.000000-07:00", # first "batch": "2026-09-22T11:00:00.000000-07:00"} # second for e in raw["marks"]: e["created"] = stamps[e["id"]] (b / ".marks.json").write_text(json.dumps(raw)) page = _open(browser, base, "b", f"{SEAM}", b) page.wait_for_selector(".bk-ask") ids = page.eval_on_selector_all("[id^='bk-ask-']", "els => els.map(e => e.id)") batch = [i for i, v in enumerate(ids) if "batch" in v] winner = [i for i, v in enumerate(ids) if "winner" in v] assert batch and winner, ids # winner (created first) ahead of batch (created second) — the OPPOSITE of # alphabetical, so an id sort cannot pass this. assert max(winner) < min(batch), ids page.close() # ---- the one that actually matters ------------------------------------------ def test_a_form_scattered_down_the_report_submits_every_question(browser, live): """THE load-bearing browser test. Four radio groups under four different artifacts, one somewhere else entirely, bound only by the HTML5 `form=` attribute — and now inserted into a live document in visual order, which means a control can land before the form it points at. If form-owner resolution does not survive that, the operator fills the whole thing in and the button saves nothing. It was true by construction before U3 (static HTML, resolved at parse). It is true by measurement now. That is the trade this test pays for. """ base, data = live b = _multi(data / "b") page = _open(browser, base, "b", REPORT, b) page.wait_for_selector("#lawson .bk-ask") page.check('#lawson input[name="choice.r1"][value="keep"]') page.check('#jo input[name="choice.r2"][value="cut"]') with page.expect_navigation(): page.click("button.bk-ask-go") ans = _answer(b) assert ans is not None, "the scattered form submitted nothing" assert ans["answers"]["r1"]["choice"] == "keep" assert ans["answers"]["r2"]["choice"] == "cut", \ "a question bound by form= did not reach the POST" assert ans["complete"] is True page.close() def test_the_chip_jumps_to_the_first_fragment_of_the_open_ask(browser, live): base, data = live b = _multi(data / "b") page = _open(browser, base, "b", REPORT, b) page.wait_for_selector(".booth-nav-asks") chip = page.locator(".booth-nav-asks") assert chip.inner_text() == "? 1 open ask" target = chip.get_attribute("href") # the EARLIEST match in document order, not merely a match: the report # anchors r1 above r2 above the submit block, so any later one is wrong. ids = page.eval_on_selector_all("[id^='bk-ask-batch']", "els => els.map(e => e.id)") assert ids, "no batch fragment mounted" assert target == "#" + ids[0], (target, ids) page.close() def test_an_anchor_named_like_an_object_property_does_not_kill_the_page(browser, live): """`toString` is a legal mark id (`asks.valid_stem`) and therefore a legal thing for an author to typo into an anchor. Against a plain `{}` lookup it came back as Object.prototype.toString — truthy, so it sailed past the unknown-mark guard and threw on `.questions.length`, aborting placement before the tail and costing the page EVERY ask. One typo, no chrome, no error the operator would see. Found by a cross-frontier panel.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", ( '
' f'
{SEAM}'), b) page.wait_for_selector(".bk-ask") assert page.locator("#t").inner_html().strip() == "" # left alone assert page.locator("#v").inner_html().strip() == "" # left alone # and the real ask still mounted, which is what the bug destroyed assert page.locator('input[name="choice.r1"]').count() == 2 assert page.locator('input[name="choice.r2"]').count() == 2 assert page.locator("form#bk-ask-form-batch").count() == 1 page.close() def test_a_question_keyed_like_an_object_property_is_not_swallowed(browser, live): """The mirror of the same bug, on the `placed` set. `constructor` matches `asks._KEY_RE`, and against a plain object an inherited `got.constructor` read as ALREADY PLACED — so a question the author did not anchor was silently dropped from the tail, which is INV-7's whole subject.""" from booth.marks import declare_pick base, data = live b = data / "b" b.mkdir(parents=True, exist_ok=True) declare_pick(b, "batch", {"title": "Round one", "questions": [ {"key": "r1", "prompt": "First?", "options": ["keep", "cut"]}, {"key": "constructor", "prompt": "Second?", "options": ["keep", "cut"]}, ]}) page = _open(browser, base, "b", f'
{SEAM}', b) page.wait_for_selector("form#bk-ask-form-batch", state="attached") assert page.locator('input[name="choice.r1"]').count() == 2 assert page.locator('input[name="choice.constructor"]').count() == 2, \ "an unplaced question was swallowed by an inherited property" page.close() def test_a_submit_anchor_inside_the_authors_own_form_still_submits(browser, live): """A submit anchor placed inside the author's own `` loses ours: the HTML parser drops a nested form element outright. The controls' `form=` then points at nothing, the button does nothing, and the operator finds out by filling the whole thing in. Found by a cross-frontier bug-hunt panel; the fix is to count the anchor submitted only if the form actually survived, so the tail supplies one at body level where no form encloses it.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", ( '' '
' '
' '' '
' f"{SEAM}"), b) page.wait_for_selector("form#bk-ask-form-batch", state="attached") assert page.locator("form#bk-ask-form-batch").count() == 1 page.check('input[name="choice.r1"][value="keep"]') page.check('input[name="choice.r2"][value="cut"]') with page.expect_navigation(): page.click("button.bk-ask-go") ans = _answer(b) assert ans is not None, "the button reached no form" assert ans["answers"]["r1"]["choice"] == "keep" assert ans["answers"]["r2"]["choice"] == "cut" page.close() def test_a_broken_pick_shows_its_diagnostic_even_from_a_submit_anchor(browser, live): """A broken pick has no submit block — its `submit` is empty and the diagnostic lives in `whole`. Mounting that empty string and then recording the pick as placed made the tail skip it, so the 'broken ask' box never rendered at the one surface built to show it. A question the session believes it posted has to be visible.""" base, data = live b = _single(data / "b") raw = json.loads((b / ".marks.json").read_text()) raw["marks"][0]["declaration"] = {"prompt": "p"} # no options -> AskError (b / ".marks.json").write_text(json.dumps(raw)) page = _open(browser, base, "b", f'
' f"
{SEAM}", b) page.wait_for_selector(".bk-ask") assert page.locator("#s").inner_html().strip() == "" # anchor left alone # inner_text() is the RENDERED text, and `.bk-ask-tag` is uppercased by CSS — # so assert the diagnostic itself, which is the part that has to reach him. shown = page.locator("body").inner_text() assert "this question could not be read" in shown, shown assert "options" in shown # the actual reason page.close() def test_an_author_element_cannot_hijack_the_chip(browser, live): """`
` satisfies any id-prefix rule, hyphen boundary included. The chip therefore searches only the elements THIS SCRIPT MOUNTED — the identity the deleted `bk-ask--top` anchor used to guarantee — and takes the earliest of those in document order.""" base, data = live b = _single(data / "b") page = _open(browser, base, "b", ( '
notes
' f"

report

{SEAM}"), b) page.wait_for_selector(".booth-nav-asks") target = page.locator(".booth-nav-asks").get_attribute("href") assert target != "#bk-ask-winner-background" landed = page.locator(target) assert landed.count() == 1 assert landed.evaluate("e => e.classList.contains('bk-ask')"), \ "the chip jumped to something the Booth did not mount" page.close() def test_the_chip_does_not_jump_to_a_mark_that_merely_shares_a_prefix(browser, live): """A SIBLING MARK's fragment must not take the chip, even when it is earlier in the document. `batch2`'s id starts with `batch`, so the original id-prefix rule could land on it; the mounted-elements rule cannot, because the candidates are partitioned by mark. ⚠ The first version of this test put the sibling's fragment AFTER the open mark's, so the right answer was also the first answer and pooling every mark's elements passed it. The vacuity pass caught that; the fixture now puts the sibling FIRST, which is the only arrangement that can tell the two implementations apart. """ from booth.marks import declare_pick base, data = live b = _multi(data / "b") # `batch`, created first declare_pick(b, "batch2", {"prompt": "Unrelated?", "options": ["x", "y"]}) # batch2 is anchored at the very top; batch is unanchored and so lands in # the tail, at the END of the body. Document order is therefore batch2's # fragments, then batch's. page = _open(browser, base, "b", ( '
' f"

report

{SEAM}"), b) page.wait_for_selector(".booth-nav-asks") ids = page.eval_on_selector_all("[id^='bk-ask-']", "els => els.map(e => e.id)") assert any("batch2" in i for i in ids) and any( "batch2" not in i and "batch" in i for i in ids), ids assert ids.index(next(i for i in ids if "batch2" in i)) < \ ids.index(next(i for i in ids if "batch2" not in i and "batch" in i)), \ f"fixture is wrong: the sibling must come FIRST, got {ids}" # `open` is (created, id) -> batch before batch2, so the chip targets batch target = page.locator(".booth-nav-asks").get_attribute("href") assert "batch2" not in target, f"the chip landed on the sibling mark: {target}" assert target.startswith("#bk-ask-batch") assert page.locator(target).count() == 1 page.close() def test_the_canonical_attribute_wins_when_both_are_present(browser, live): """`data-booth-mark` is canonical and `data-booth-ask` is the kept alias. An element carrying both is not a case any live report has, but the precedence has to be decided somewhere rather than by selector order.""" base, data = live b = _multi(data / "b") page = _open(browser, base, "b", ( '
{SEAM}'), b) page.wait_for_selector("#a .bk-ask") assert page.locator('#a input[name="choice.r2"]').count() == 2 # canonical assert page.locator('#a input[name="choice.r1"]').count() == 0 # alias ignored # r1 was never placed, so INV-7 still puts it somewhere assert page.locator('input[name="choice.r1"]').count() == 2 page.close() def test_the_chip_count_comes_from_the_server(browser, live): """INV-4. A half-answered multi-question pick is STILL OPEN, and the page does not get to have an opinion about that — `open_marks` decides.""" from booth.marks import answer_pick base, data = live b = _multi(data / "b") answer_pick(b, "batch", {"r1": "keep"}) page = _open(browser, base, "b", REPORT, b) page.wait_for_selector(".bk-ask") assert page.locator(".booth-nav-asks").count() == 1 answer_pick(b, "batch", {"r1": "keep", "r2": "cut"}) page.reload(wait_until="networkidle") page.wait_for_selector(".bk-ask") assert page.locator(".booth-nav-asks").count() == 0 page.close() def test_the_chip_follows_a_payload_that_disagrees_with_the_fragments(browser, live): """INV-4, and the version that actually falsifies it. The test above uses honest fixtures, so a client that INFERRED openness from the rendered fragments would pass it — the fragments and `open` always agree when the server computes both. A panel pointed out that this never creates the disagreement it claims to test. So: intercept the response and make `open` lie. The fragments say fully answered; the payload says two are open. The chip must follow the payload, because the payload is the only thing that decides. """ import json as _json from booth.marks import answer_pick base, data = live b = _multi(data / "b") answer_pick(b, "batch", {"r1": "keep", "r2": "cut"}) # nothing is open (b / "index.html").write_text(f"{SEAM}", encoding="utf-8") def lie(route): body = _json.loads(route.fetch().text()) assert body["open"] == [], "fixture is not answered; the lie would be true" body["open"] = ["batch", "batch"] route.fulfill(status=200, content_type="application/json", body=_json.dumps(body)) page = browser.new_page() page.route("**/embed.json", lie) page.goto(f"{base}/b/b/", wait_until="networkidle") page.wait_for_selector(".booth-nav-asks") assert page.locator(".booth-nav-asks").inner_text() == "? 2 open asks" page.close()