test(FN-000): harden local test suite

packages/engine/src/__tests__/task-completion.test.ts

@@ -0,0 +1,39 @@
+import { describe, expect, it, vi } from "vitest";
+import type { TaskDetail } from "@fusion/core";
+import { getTaskCompletionBlockerForStore } from "../task-completion.js";
+
+function createTask(overrides: Partial<TaskDetail> = {}): TaskDetail {
+  const now = new Date().toISOString();
+  return {
+    id: "FN-100",
+    description: "Task",
+    prompt: "Task prompt",
+    column: "in-progress",
+    dependencies: [],
+    steps: [],
+    currentStep: 0,
+    log: [],
+    createdAt: now,
+    updatedAt: now,
+    ...overrides,
+  };
+}
+
+describe("getTaskCompletionBlockerForStore", () => {
+  it("treats dependency lookup failures as unresolved dependencies", async () => {
+    const getTask = vi.fn(async (taskId: string) => {
+      if (taskId === "FN-DONE") {
+        return createTask({ id: taskId, column: "done" });
+      }
+      throw new Error("database temporarily unavailable");
+    });
+
+    await expect(getTaskCompletionBlockerForStore(
+      { getTask },
+      createTask({ dependencies: ["FN-DONE", "FN-MISSING"] }),
+    )).resolves.toBe("task has unresolved dependencies: FN-MISSING");
+
+    expect(getTask).toHaveBeenCalledWith("FN-DONE");
+    expect(getTask).toHaveBeenCalledWith("FN-MISSING");
+  });
+});