title: Authorization header isn't mocked
body: <p>thunk that makes async call </p>
  
  <pre><code>buyerAction = (data = {}, cb) =&gt; (dispatch) =&gt; {
    console.log('x-access-token', authService.getAccessToken());
    axios({
      method: 'POST',
      url: `http://localhost:3001/api/manageUsers`,
      headers: {
        'x-access-token': authService.getAccessToken()
      },
      data
    }).then((res) =&gt; {
      if (res.status === 200 &amp;&amp; res.data) {
        dispatch({ type: 'buyer_created', data: res.data.message });
        if (data.role === 'buyer') {
          axios({
            method: 'POST',
            url: `http://localhost:3001/api/populateBuyerLookUp`,
            headers: {
              'x-access-token': authService.getAccessToken()
            },
            data
          }).then((response) =&gt; {
            console.log(`${response} lookup is created`);
          }).catch((err) =&gt; { console.log(err); });
        }
        cb(res.data.message);
      }
    })
      .catch((err) =&gt; { console.log('_+_+_+', err); });
  };
  </code></pre>
  
  <p>trying to test :</p>
  
  <pre><code>const middleware = [thunk];
  const mockStore = configureMockStore(middleware);
  
  describe('Async Actions', () =&gt; {
    const host = 'http://localhost';
  
    axios.defaults.host = host;
    axios.defaults.adapter = httpAdapter;
  
    afterEach(() =&gt; {
      nock.cleanAll();
    });
  
    it('should create Async and load data', (done) =&gt; {
      nock('http://localhost:3001', {
        reqheaders: {
          'x-access-token': 'authtoken'
        }
      })
        .post('/api/manageUsers')
        .reply(200, { body: { name: 'prakash' } });
  
      const store = mockStore({}, [{ type: 'buyer_created', data: 'message' }]);
  
      store.dispatch(buyerAction(undefined, () =&gt; {}));
  
      done();
    });
  });
  </code></pre>
  
  <p>Error: x-access-token undefined
  TypeError [ERR_HTTP_INVALID_HEADER_VALUE]: Invalid value "undefined" for header "x-access-token"</p>
  
  <p>I am trying to test thunk with nock, is there any better and simple approach to test thunk and mock header?</p>