javascript – 酶模拟onChange事件

我正在用摩卡和酶测试反应成分.这是组件(当然简化为简化)：

class New extends React.Component {

  // shortened for simplicity

  handleChange(event) {
    // handle changing state of input

    const target = event.target;
    const value = target.value;
    const name = target.name
    this.setState({[name]: value})

  }


  render() {
    return(
      <div>
        <form onSubmit={this.handleSubmit}>
          <div className="form-group row">
            <label className="col-2 col-form-label form-text">Poll Name</label>
            <div className="col-10">
              <input
                className="form-control"
                ref="pollName"
                name="pollName"
                type="text"
                value={this.state.pollName}
                onChange={this.handleChange}
              />
            </div>
          </div>

          <input className="btn btn-info"  type="submit" value="Submit" />
        </form>
      </div>
    )
  }
}

以下是测试：

it("responds to name change", done => {
  const handleChangeSpy = sinon.spy();
  const event = {target: {name: "pollName", value: "spam"}};
  const wrap = mount(
    <New handleChange={handleChangeSpy} />
  );

  wrap.ref('pollName').simulate('change', event);
  expect(handleChangeSpy.calledOnce).to.equal(true);
})

我希望当用户在< input>中键入文本时框中将调用handleChange方法.以上测试失败：

AssertionError: expected false to equal true
+ expected - actual

-false
+true

at Context.<anonymous> (test/components/new_component_test.js:71:45)

我究竟做错了什么？

编辑

我应该澄清一下,我的目标是测试方法handleChange是否被调用.我怎样才能做到这一点？

解决方法:

您可以通过原型直接窥探方法.

it("responds to name change", done => {
  const handleChangeSpy = sinon.spy(New.prototype, "handleChange");
  const event = {target: {name: "pollName", value: "spam"}};
  const wrap = mount(
    <New />
  );
  wrap.ref('pollName').simulate('change', event);
  expect(handleChangeSpy.calledOnce).to.equal(true);
})

或者,您可以在实例的方法上使用spy,但是您必须进行强制更新,因为在调用mount之后该组件已经呈现,这意味着onChange已经绑定到其原始.

it("responds to name change", done => {
  const event = {target: {name: "pollName", value: "spam"}};
  const wrap = mount(
    <New />
  );
  const handleChangeSpy = sinon.spy(wrap.instance(), "handleChange");
  wrap.update(); // Force re-render
  wrap.ref('pollName').simulate('change', event);
  expect(handleChangeSpy.calledOnce).to.equal(true);
})

标签：enzyme,javascript,reactjs,mocha
来源： https://codeday.me/bug/20190926/1818939.html