How to use the shipjs-lib.getCurrentBranch.mockImplementation function in shipjs-lib

it('does not return error if current branch is correct', () => {
    getCurrentBranch.mockImplementation(() => 'master');
    const result = validate(defaultOpts);
    expect(result).toBe(true);
  });

it('works', () => {
    validateBeforePrepare.mockImplementation(() => true);
    const version = '1.2.3';
    const branch = 'legacy';
    getCurrentVersion.mockImplementation(() => version);
    getCurrentBranch.mockImplementation(() => branch);
    const { currentVersion, baseBranch } = validate({
      config: {
        getTagName: () => 'v1.2.3',
        mergeStrategy: {
          toSameBranch: ['master'],
          toReleaseBranch: {
            legacy: 'v1',
          },
        },
      },
    });
    expect(currentVersion).toEqual(version);
    expect(baseBranch).toEqual(branch);
    expect(exitProcess).toHaveBeenCalledTimes(0);
  });