测试功能解析和拒绝

Question

使用Jest和Enzyme运行测试。此刻测试通过了，但是当我运行npm测试报道时，某些行被覆盖了，但是最后几行丢失了

    patchSourceEntity = () => {
    return new Promise((resolve, reject) => {
      let SourceEntityBody = { 
        FirmID: this.props.FirmId,
        Name: this.state.Name,
        ShortName: this.state.ShortName,
        SourceEntityTypeID: this.state.SourceEntityTypeID ? this.state.SourceEntityTypeID.value : null
      }

      fetch(`${this.props.services.MasterDB.URL}/SOURCE_ENTITY?id=${this.props.entityToEdit}`, {
        headers: {          
          'Content-Type': 'application/json',
          'Ocp-Apim-Subscription-Key': this.props.services.MasterDB.subscription_key,
          "DDHFirm": this.props.user.DDHFirm,
          'x-universal-firm': this.props.FirmId,
        },
        method: 'PATCH',
        credentials: 'include',
        body: JSON.stringify(SourceEntityBody),
        }).then(
          res => {return(validationManager.ResolveHTTPResponse(res, 'Request Successful', 'Request Failed', false))
        }).then(response => {
          if(!response.error) {
            resolve();
          } else {
            reject();
          }        
        })
    })
   }

我嘲笑该函数：

const patchSourceEntity = jest.fn( () => {
return new Promise((resolve, reject) => {
resolve()
})})

并调用了函数：

expect(wrapper.find('SourceEntityForm').instance().patchSourceEntity()).toBeDefined()

为了使测试覆盖率达到100％，我还可以在测试中添加些什么