From ddd1c7bd6fa33202fa8b418e1ce998d058e26e44 Mon Sep 17 00:00:00 2001
From: robbond <rob@rdbsolutions.co.uk>
Date: Thu, 8 Oct 2026 06:45:37 +0100
Subject: [PATCH] test(confidence-engine): cover CU diagnostics and
 investigation checkpoints

---
 .../current-understanding-synthesis.test.js   | 105 ++++++++++++++++++
 ...date-experiment-helper-checkpoint.test.cjs |   2 +-
 2 files changed, 106 insertions(+), 1 deletion(-)

diff --git a/tests/graph/current-understanding-synthesis.test.js b/tests/graph/current-understanding-synthesis.test.js
index e538e64..673bc59 100644
--- a/tests/graph/current-understanding-synthesis.test.js
+++ b/tests/graph/current-understanding-synthesis.test.js
@@ -635,4 +635,109 @@ describe("synthesizeCurrentUnderstanding — full seam", () => {
       )
     ).rejects.toThrow(/Synthesis validation failed/);
   });
+
+  // ── Batch 3 Iteration 1: CU synthesis observability (sanitized diagnostic) ──
+
+  it("validation failure exposes sanitizedDiagnostic with safe shape fields — no content leaked", async () => {
+    const fake = makeFakeProvider(async () => JSON.stringify({ wrongField: "value" }));
+    try {
+      await synthesizeCurrentUnderstanding(
+        { situationGraph: fullScenario, findings: [] },
+        { provider: fake }
+      );
+    } catch (err) {
+      expect(err.message).toMatch(/Synthesis validation failed/);
+      expect(err.statusCode).toBe(502);
+      expect(err.sanitizedDiagnostic).toBeDefined();
+      expect(err.sanitizedDiagnostic).toBeInstanceOf(Object);
+
+      const d = err.sanitizedDiagnostic;
+
+      // T1: providerApiPath exposed as string or null (safe)
+      expect(d.providerApiPath).toBeDefined();
+      expect(typeof d.providerApiPath).toMatch(/string|number|boolean|undefined|null/);
+
+      // T2: responseType is a safe primitive exposing typeof the response
+      expect(typeof d.responseType).toBe("string");
+
+      // T3: responseIsNull boolean (safe)
+      expect(typeof d.responseIsNull).toBe("boolean");
+
+      // T4: hasCurrentUnderstanding boolean — proves structural detection works
+      expect(typeof d.hasCurrentUnderstanding).toBe("boolean");
+
+      // T5: currentUnderstandingType is null when field absent (safe)
+      expect(d.currentUnderstandingType).toBeNull();
+
+      // T6: currentUnderstandingLength is null when field absent (safe)
+      expect(d.currentUnderstandingLength).toBeNull();
+
+      // T7: responseKeys reveals shape but never CU text — wrongField is safe key
+      expect(Array.isArray(d.responseKeys)).toBe(true);
+      expect(d.responseKeys).toContain("wrongField");
+    }
+  });
+
+  it("sanitizedDiagnostic does NOT include actual CU narrative content", async () => {
+    const fake = makeFakeProvider(async () => JSON.stringify({ currentUnderstanding: "Should not appear in diagnostic" }));
+    try {
+      await synthesizeCurrentUnderstanding(
+        { situationGraph: fullScenario, findings: [] },
+        { provider: fake }
+      );
+    } catch (err) {
+      expect(err.sanitizedDiagnostic).toBeDefined();
+      const d = err.sanitizedDiagnostic;
+      // The diagnostic should expose length but not content
+      expect(typeof d.currentUnderstandingLength).toBe("number");
+      // Length 43 for "Should not appear in diagnostic" — if it were wrongField the field wouldn't exist so hasCU would be false and length would be null
+      expect(d.hasCurrentUnderstanding).toBe(true);
+      // Crucially: actual content string must NOT appear anywhere in diagnostic
+      const diagStr = JSON.stringify(d);
+      expect(diagStr).not.toContain("Should not appear");
+    }
+  });
+
+  it("provider returns response object (already parsed) with valid currentUnderstanding — no synthetic test", async () => {
+    const fake = makeFakeProvider(); // default: returns JSON stringified valid output
+    const result = await synthesizeCurrentUnderstanding(
+      { situationGraph: fullScenario, findings: [workingFinding()] },
+      { provider: fake }
+    );
+    expect(result).toEqual({ currentUnderstanding: "Synthesized output" });
+  });
+
+  it("validateSynthesisResponse with response that is a plain object (not string) — still valid", async () => {
+    const fake = makeFakeProvider(async () => ({ currentUnderstanding: "from-object" }));
+    const result = await synthesizeCurrentUnderstanding(
+      { situationGraph: fullScenario, findings: [] },
+      { provider: fake }
+    );
+    expect(result).toEqual({ currentUnderstanding: "from-object" });
+  });
+
+  it("responseKeys exposed in diagnostic includes top-level keys of any response object", async () => {
+    const fake = makeFakeProvider(async () => JSON.stringify({ foo: 1, bar: "baz", currentUnderstanding: "x" }));
+    try {
+      await synthesizeCurrentUnderstanding(
+        { situationGraph: fullScenario, findings: [] },
+        { provider: fake }
+      );
+    } catch (err) {
+      expect(err.sanitizedDiagnostic.responseKeys).toEqual(["bar", "currentUnderstanding", "foo"]);
+    }
+  });
+
+  it("validation success returns normal result — no diagnostic attached", async () => {
+    const fake = makeFakeProvider();
+    try {
+      await synthesizeCurrentUnderstanding(
+        { situationGraph: fullScenario, findings: [] },
+        { provider: fake }
+      );
+    } catch (err) {
+      // Should not reach here — success path should not throw
+      expect(err).toBeUndefined();
+    }
+  });
 });
diff --git a/tests/graph/live-update-experiment-helper-checkpoint.test.cjs b/tests/graph/live-update-experiment-helper-checkpoint.test.cjs
index eb54697..1bcdaab 100644
--- a/tests/graph/live-update-experiment-helper-checkpoint.test.cjs
+++ b/tests/graph/live-update-experiment-helper-checkpoint.test.cjs
@@ -685,7 +685,7 @@ async function runSyntheticTests() {
 }
 
 // Run synthetic tests and exit with combined result
-var synPromise = runSyntheticTests().then(function(synthFail) {
+runSyntheticTests().then(function(synthFail) {
   var totalFailures = failures + synthFail;
   process.exit(totalFailures > 0 ? 1 : 0);
 });
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