feat(linkedin): add fact-checker agent + fixture (S4)

plugins/linkedin-thought-leadership/agents/__tests__/fact-checker-fixture.test.mjs

@@ -0,0 +1,61 @@
+import { describe, test } from 'node:test';
+import assert from 'node:assert/strict';
+import { readFileSync } from 'node:fs';
+import { fileURLToPath } from 'node:url';
+
+// Lint-test for the fact-checker fasit fixture.
+// Mirrors the structure-only discipline of state-updater.test.mjs: this test
+// asserts the SHAPE of the fixture (exactly 3 cases, one of each verdict, a
+// non-empty fasit per case). The accuracy comparison — does the agent's live
+// output actually match the fasit verdicts — is [GATE]/[OPERATØR], never
+// self-certified here.
+
+const FIXTURE_PATH = fileURLToPath(
+  new URL('../fixtures/fact-checker-cases.md', import.meta.url)
+);
+const VERDICTS = ['🟢', '🔴', '🟡'];
+
+const fixture = readFileSync(FIXTURE_PATH, 'utf8');
+
+// Split on "## Case N" headings; drop the preamble before the first case.
+const blocks = fixture
+  .split(/^##\s+Case\s+\d+\b.*$/m)
+  .slice(1)
+  .map((b) => b.trim());
+
+describe('fact-checker fixture structure', () => {
+  test('contains exactly 3 cases', () => {
+    assert.equal(blocks.length, 3, `expected 3 cases, found ${blocks.length}`);
+  });
+
+  test('each case carries exactly one verdict emoji', () => {
+    for (const [i, block] of blocks.entries()) {
+      const present = VERDICTS.filter((v) => block.includes(v));
+      assert.equal(
+        present.length,
+        1,
+        `case ${i + 1} must have exactly one of 🟢/🔴/🟡, found: [${present.join(', ')}]`
+      );
+    }
+  });
+
+  test('the three verdicts are one each of 🟢/🔴/🟡', () => {
+    const seen = blocks.map((b) => VERDICTS.find((v) => b.includes(v)));
+    assert.deepEqual(
+      [...seen].sort(),
+      [...VERDICTS].sort(),
+      `fixture must cover one true (🟢), one false (🔴), one unverifiable (🟡); saw ${JSON.stringify(seen)}`
+    );
+  });
+
+  test('each case has a non-empty Fasit field', () => {
+    for (const [i, block] of blocks.entries()) {
+      const m = block.match(/\*\*Fasit:\*\*\s*(.+)/);
+      assert.ok(m, `case ${i + 1} is missing a **Fasit:** field`);
+      assert.ok(
+        m[1].trim().length > 0,
+        `case ${i + 1} has an empty **Fasit:** field`
+      );
+    }
+  });
+});