Show what would act on a screen as a picture on every surface, and keep a value's bidi within it

Speech wrote a value's C1 controls (U+009B is a CSI to some terminals),
DEL, line separators and bidi overrides as they were; the CLI and the
TUI wrote line separators (a pipe's reader may break its line there) and
the controls that turn text around (a terminal then reverses the rest of
its line, other values' cells too); the web page showed controls as they
were and let a label's override reverse its badge. Now every surface
shows controls, DEL, C1 and line and paragraph separators as pictures
(vega_visible); a terminal's cells show embeddings, overrides and
isolates as U+FFFD too (vega_cell); speech says a space for the one and
nothing for the other; the page shows the pictures and isolates each
value, while /screen's JSON keeps values as they are. screen_meaning
checks the CLI, the TUI, speech and the JSON against that rule, and that
nothing a value holds reaches any output as a control; the browser check
sees the page show it.

1 files changed, 4 insertions, 0 deletions

diff --git a/tests/browser.mjs b/tests/browser.mjs
index 0f77585..15c94a8 100644
--- a/tests/browser.mjs
+++ b/tests/browser.mjs
@@ -129,6 +129,10 @@ try {
     [a.options.map(name), await evaluate(places)]);
   const entry = a.nodes.find(n => role(n) === 'textbox');
   check('the text input is named for its input', entry && name(entry) === 'add', entry);
+  // A value holding what would act on a screen: shown as the other surfaces show it, its bidi kept within it.
+  await evaluate(`post('/text', 'esc \\u001b[31m sep \\u2028 rlo \\u202e.')`);
+  await until('a value is shown as the other surfaces show it', `document.querySelectorAll('li')[4]?.querySelector('.label').textContent === 'esc \\u241b[31m sep \\u2424 rlo \\u202e.'`);
+  check('its bidi stays within it', await evaluate(`getComputedStyle(document.querySelectorAll('li')[4].querySelector('.label')).unicodeBidi`) === 'isolate', null);
   await finish(true);
 } catch (error) {
   await finish(false, String(error.message || error));