Test & mock private function by jest

guide-mock-private-func-by-jest.md

export class Test {
  constructor() {}

  private testPri(a: string): string {
    return a + 'test';
  }
}

describe("Test", () => {
  
  it("test private function", async () => {
    const test = new Test();
    const r = test["testPri"]("a");
    expect(r).toBe("atest");
  });
  it("mock private function", async () => {
    const test = new Test();
    jest.spyOn(test as any, "testPri").mockReturnValue("token");
    const r = test["testPri"]("a");
    expect(r).toBe("token");
  });
});