test: add error handling tests for closeMultiModel and openMultiModel

tests/close_error.test.ts

@@ -0,0 +1,53 @@
+import { expect, test, mock, beforeEach, afterEach, describe, spyOn } from "bun:test";
+import * as os from "node:os";
+import { closeMultiModel } from "../src/core/close";
+
+let originalBun$: typeof Bun.$ = (globalThis as any).Bun?.$;
+let mockCommandResponses: Record<string, { ok: boolean; stdout: string; stderr: string }> = {};
+let executedCommands: string[] = [];
+
+function setupMockBun$() {
+  const mockFn = mock((strings: TemplateStringsArray, ...values: any[]) => {
+    const parts = values[0] as string[];
+    const cmd = parts.join(" ");
+    executedCommands.push(cmd);
+    // Simulate throwing error for a specific command
+    if (cmd === "git worktree list --porcelain") {
+      throw new Error("unexpected error");
+    }
+    const response = mockCommandResponses[cmd] ?? { ok: true, stdout: "", stderr: "" };
+    return {
+      quiet: () => ({
+        nothrow: async () => ({
+          exitCode: response.ok ? 0 : 1,
+          stdout: { toString: () => response.stdout },
+          stderr: { toString: () => response.stderr },
+        }),
+      }),
+    };
+  });
+  (globalThis as any).Bun.$ = mockFn;
+  return mockFn;
+}
+
+function restoreOriginalBun$() {
+  (globalThis as any).Bun.$ = originalBun$;
+}
+
+describe("closeMultiModel unexpected error handling", () => {
+  beforeEach(() => {
+    spyOn(os, "homedir").mockReturnValue("/home/user");
+    mockCommandResponses = {};
+    executedCommands = [];
+    setupMockBun$();
+  });
+  afterEach(() => {
+    restoreOriginalBun$();
+  });
+
+  test("catches thrown error and returns failure", async () => {
+    const result = await closeMultiModel({ sessionName: "any-session", cleanupWorktrees: false, force: false });
+    expect(result.success).toBe(false);
+    expect(result.error).toContain("unexpected error");
+  });
+});