swarm-ui: a broadcast page that sends one message to several agents

Pick agents from a grid of their icons (running or all), type the text, send.
The page posts the names and the text to the controller and shows what
happened to each agent, with a retry that selects just the ones that failed.
The selection rules and the controller's answer are read by plain functions
with tests.

frontend/packages/swarm-ui/test/broadcast-types.test.mjs

@@ -0,0 +1,96 @@
+// The broadcast page's selection and answer rules. Run by `npm test`, which
+// Node runs with its built-in test runner and type stripping, so the `.ts`
+// module is imported as it is.
+import assert from "node:assert/strict";
+import { test } from "node:test";
+import {
+  failedAgents,
+  MAX_BROADCAST,
+  isRunning,
+  parseResults,
+  selectedVisible,
+  sendLabel,
+  tickAll,
+  toggled,
+  visibleAgents,
+} from "../src/pages/broadcast/broadcast-types.ts";
+
+const up = { running: true };
+const down = { running: false };
+const agents = [
+  { name: "zed", snapshot: up },
+  { name: "bob", snapshot: down },
+  { name: "ann", snapshot: null },
+  { name: "cy", snapshot: up },
+];
+
+test("only an agent that reported running counts as running", () => {
+  assert.equal(isRunning({ snapshot: up }), true);
+  assert.equal(isRunning({ snapshot: down }), false);
+  assert.equal(isRunning({ snapshot: null }), false);
+});
+
+test("the filter shows every agent or just the running ones, by name", () => {
+  assert.deepEqual(
+    visibleAgents(agents, "all").map((a) => a.name),
+    ["ann", "bob", "cy", "zed"],
+  );
+  assert.deepEqual(
+    visibleAgents(agents, "running").map((a) => a.name),
+    ["cy", "zed"],
+  );
+});
+
+test("a ticked agent the filter hides is not sent to, and comes back with the filter", () => {
+  const ticked = ["bob", "cy"];
+  const running = visibleAgents(agents, "running");
+  assert.deepEqual(selectedVisible(ticked, running), ["cy"]);
+  assert.deepEqual(selectedVisible(ticked, visibleAgents(agents, "all")), [
+    "bob",
+    "cy",
+  ]);
+});
+
+test("toggling flips one name and keeps the rest", () => {
+  assert.deepEqual(toggled(["a", "b"], "c"), ["a", "b", "c"]);
+  assert.deepEqual(toggled(["a", "b"], "a"), ["b"]);
+});
+
+test("tick all adds the shown agents once", () => {
+  const shown = visibleAgents(agents, "running");
+  assert.deepEqual(tickAll(["cy", "bob"], shown), ["cy", "bob", "zed"]);
+});
+
+test("the send button says how many it goes to", () => {
+  assert.equal(sendLabel(0), "send");
+  assert.equal(sendLabel(1), "send to 1 agent");
+  assert.equal(sendLabel(3), "send to 3 agents");
+});
+
+test("the controller's answer is read per agent", () => {
+  const results = parseResults({
+    results: [
+      { agent: "a", sent: true },
+      { agent: "b", sent: false, reason: "no subscriber" },
+      { agent: "c", sent: false, reason: "" },
+    ],
+  });
+  assert.deepEqual(results, [
+    { agent: "a", sent: true, reason: null },
+    { agent: "b", sent: false, reason: "no subscriber" },
+    { agent: "c", sent: false, reason: null },
+  ]);
+  assert.deepEqual(failedAgents(results ?? []), ["b", "c"]);
+});
+
+test("an answer that is not the agreed shape is null, not an empty list", () => {
+  assert.equal(parseResults(null), null);
+  assert.equal(parseResults({}), null);
+  assert.equal(parseResults({ results: "x" }), null);
+  assert.equal(parseResults({ results: [{ agent: "a" }] }), null);
+  assert.equal(parseResults({ results: [null] }), null);
+});
+
+test("one broadcast may name at most 64 agents", () => {
+  assert.equal(MAX_BROADCAST, 64);
+});