I ran into this issue too - `Error:

import { defineWorkersConfig } from "@cloudflare/vitest-pool-workers/config";

export default defineWorkersConfig({
  test: {
    name: "example-worker",
    server: {
      deps: {
        inline: [
          // /@hono\/zod-validtor/,
          // /@hono\/zod-openapi/,
          // /zod-to-openapi/,
          // Without this, there is an error
          //    TypeError: Cannot read properties of undefined (reading 'bold')
          // in `monorepo/node_modules/.pnpm/[email protected][email protected]/node_modules/inngest/index.js?mf_vitest_no_cjs_esm_shim:6:17`
          /inngest/,
        ],
      },
    },
    poolOptions: {
      workers: {
        main: "src/index.ts",
        wrangler: { configPath: "./wrangler.json" },
        miniflare: {
          compatibilityFlags: ["nodejs_compat"],
        },
      },
    },
  },
});

import { defineWorkersConfig } from "@cloudflare/vitest-pool-workers/config";

export default defineWorkersConfig({
  test: {
    name: "example-worker",
    server: {
      deps: {
        inline: [
          // /@hono\/zod-validtor/,
          // /@hono\/zod-openapi/,
          // /zod-to-openapi/,
          // Without this, there is an error
          //    TypeError: Cannot read properties of undefined (reading 'bold')
          // in `monorepo/node_modules/.pnpm/[email protected][email protected]/node_modules/inngest/index.js?mf_vitest_no_cjs_esm_shim:6:17`
          /inngest/,
        ],
      },
    },
    poolOptions: {
      workers: {
        main: "src/index.ts",
        wrangler: { configPath: "./wrangler.json" },
        miniflare: {
          compatibilityFlags: ["nodejs_compat"],
        },
      },
    },
  },
});

import { Hono } from "hono";

type Bindings = {};

const app = new Hono<{ Bindings: Bindings }>();

app.get("/test", (c) => {
  return c.json({ success: true });
});

app.get("/inngest-test", async (c) => {
  // The same error occurs when imported at the top of the file
  // But, this way (ie, with a dynamic import), I can show `/test` works fine
  const { Inngest } = await import("inngest");
  const inngest = new Inngest({ id: "foo" });
  return c.json({ success: true, inngestClientId: inngest.id });
});

export default app;

import { Hono } from "hono";

type Bindings = {};

const app = new Hono<{ Bindings: Bindings }>();

app.get("/test", (c) => {
  return c.json({ success: true });
});

app.get("/inngest-test", async (c) => {
  // The same error occurs when imported at the top of the file
  // But, this way (ie, with a dynamic import), I can show `/test` works fine
  const { Inngest } = await import("inngest");
  const inngest = new Inngest({ id: "foo" });
  return c.json({ success: true, inngestClientId: inngest.id });
});

export default app;

import {
  createExecutionContext,
  env,
  waitOnExecutionContext,
} from "cloudflare:test";
import { describe, expect, it } from "vitest";

import worker from ".";

describe("Worker", () => {
  it("should return 200 response", async () => {
    const url = new URL("/test", "http://localhost:8787");
    const request = new Request(url, {
      method: "GET",
      headers: { "Content-Type": "application/json" },
    });
    const ctx = createExecutionContext();
    const response = await worker.fetch(request, env, ctx);
    await waitOnExecutionContext(ctx);
    expect(response.status).toBe(200);
  });

  it("should return 200 response, when inngest is imported", async () => {
    const url = new URL("/inngest-test", "http://localhost:8787");
    const request = new Request(url, {
      method: "GET",
      headers: { "Content-Type": "application/json" },
    });
    const ctx = createExecutionContext();
    const response = await worker.fetch(request, env, ctx);
    await waitOnExecutionContext(ctx);
    expect(response.status).toBe(200);
  });
});

import {
  createExecutionContext,
  env,
  waitOnExecutionContext,
} from "cloudflare:test";
import { describe, expect, it } from "vitest";

import worker from ".";

describe("Worker", () => {
  it("should return 200 response", async () => {
    const url = new URL("/test", "http://localhost:8787");
    const request = new Request(url, {
      method: "GET",
      headers: { "Content-Type": "application/json" },
    });
    const ctx = createExecutionContext();
    const response = await worker.fetch(request, env, ctx);
    await waitOnExecutionContext(ctx);
    expect(response.status).toBe(200);
  });

  it("should return 200 response, when inngest is imported", async () => {
    const url = new URL("/inngest-test", "http://localhost:8787");
    const request = new Request(url, {
      method: "GET",
      headers: { "Content-Type": "application/json" },
    });
    const ctx = createExecutionContext();
    const response = await worker.fetch(request, env, ctx);
    await waitOnExecutionContext(ctx);
    expect(response.status).toBe(200);
  });
});