diff --git a/packages/engine/src/__tests__/self-healing-db-corruption.test.ts b/packages/engine/src/__tests__/self-healing-db-corruption.test.ts
index bee1be4ac5..8d42d6d549 100644
--- a/packages/engine/src/__tests__/self-healing-db-corruption.test.ts
+++ b/packages/engine/src/__tests__/self-healing-db-corruption.test.ts
@@ -36,6 +36,25 @@ function createMockStore(overrides: Record<string, unknown> = {}): TaskStore & E
       isRunning: false,
     }),
     recordRunAuditEvent: vi.fn().mockResolvedValue(undefined),
+    /*
+    FNXC:TestInfrastructure 2026-07-29-16:45:
+    surfaceDbCorruption REFRESHES health before reading the snapshot
+    (FNXC:IncompletePgPorts 2026-07-26-20:45 — so PG connectivity is re-checked
+    rather than trusting an always-healthy sentinel). This fake carried neither
+    refresher, so the async branch fell through to `this.store.refreshDatabaseHealth()`
+    — undefined — and the step threw before reaching dispatch. Every corruption
+    assertion in this file was then measuring zero calls against a step that had
+    already aborted.
+
+    Both are NO-OPS on purpose: production ignores the refresh return value and
+    reads `this.store.getDatabaseHealth()` immediately after, so the snapshot mock
+    stays the single source of truth. Delegating them to getDatabaseHealth instead
+    would consume a SECOND value per pass from the tests that queue
+    mockReturnValueOnce sequences (one per runMaintenance), silently shifting the
+    corruption -> clear -> corruption ordering they assert.
+    */
+    refreshDatabaseHealth: vi.fn(),
+    refreshDatabaseHealthAsync: vi.fn(async () => undefined),
     ...overrides,
   }) as unknown as TaskStore & EventEmitter;
 }
diff --git a/packages/engine/src/__tests__/self-healing.test.ts b/packages/engine/src/__tests__/self-healing.test.ts
index 1b3c336679..ffc508d1c8 100644
--- a/packages/engine/src/__tests__/self-healing.test.ts
+++ b/packages/engine/src/__tests__/self-healing.test.ts
@@ -2328,7 +2328,8 @@ describe("SelfHealingManager", () => {
       expect(result).toBe(1);
       expect(store.archiveTaskAndCleanup).toHaveBeenCalledWith("FN-030");
       expect(store.archiveTaskAndCleanup).not.toHaveBeenCalledWith("FN-031");
-      expect(getSelfHealingLogger().log).toHaveBeenCalledWith(
+      // self-healing.ts:2747 emits this at DEBUG level, not log.
+      expect(getSelfHealingLogger().debug).toHaveBeenCalledWith(
         "auto-archive: archived FN-030 (age 31d, threshold 30d)",
       );
     });
diff --git a/packages/engine/src/__tests__/worktree-pool.test.ts b/packages/engine/src/__tests__/worktree-pool.test.ts
index 968fdfe3d2..8c79be90e5 100644
--- a/packages/engine/src/__tests__/worktree-pool.test.ts
+++ b/packages/engine/src/__tests__/worktree-pool.test.ts
@@ -93,9 +93,22 @@ let warnSpy: ReturnType<typeof vi.spyOn>;
 beforeEach(() => {
   errorSpy = vi.spyOn(console, "error").mockImplementation(() => {});
   warnSpy = vi.spyOn(console, "warn").mockImplementation(() => {});
+  /*
+  FNXC:TestInfrastructure 2026-07-29-17:05:
+  worktree-pool logs its checkout-failure at DEBUG level, and createLogger's debug
+  writes to console.error like the rest — but debug is GATED on FUSION_DEBUG
+  (logger.ts:43), which is unset under vitest. So the line was never emitted and
+  the two checkout-failure cases below measured zero calls. One of them is even
+  named "logs checkout -- failure at debug level" while asserting a channel debug
+  could not reach without this flag. Enabling it is what makes those assertions
+  real; re-pointing them at another channel would only describe whatever the code
+  happened to do. Deleted in afterEach so the flag cannot leak into sibling files.
+  */
+  process.env.FUSION_DEBUG = "worktree-pool";
 });
 
 afterEach(() => {
+  delete process.env.FUSION_DEBUG;
   errorSpy.mockRestore();
   warnSpy.mockRestore();
 });