How to test with jest/enzyme?

See more:

testing

Does anyone have experience testing with Jest/Enzyme?
I need to write a test that renders the first value on selection and other parameter fields are hidden. This is an example of what my code looks like:

<ParameterFieldset
              parameterName="reservoir_permeability"
              parameterLabel="Reservoir permeability"
              defaultValues={{
                fixedValue: reservoirPermeability.fixedValue,
                min: reservoirPermeability.min,
                max: reservoirPermeability.max,
                mean: reservoirPermeability.mean,
                sd: reservoirPermeability.sd,
                mode: reservoirPermeability.mode,
                values: reservoirPermeability.values,
                weights: reservoirPermeability.weights,
                valid: reservoirPermeability.valid,
              }}
            />
<ParameterFieldset
              parameterName="reservoir_porosity"
              parameterLabel="Reservoir porosity"
              defaultValues={{
                fixedValue: reservoirPorosity.fixedValue,
                min: reservoirPorosity.min,
                max: reservoirPorosity.max,
                mean: reservoirPorosity.mean,
                sd: reservoirPorosity.sd,
                mode: reservoirPorosity.mode,
                values: reservoirPorosity.values,
                weights: reservoirPorosity.weights,
                valid: reservoirPermeability.valid,
              }}/>

So when reservoir_permeability fixed value is selected the min,max etc should be hidden. As well as the options for reservoir_porosity. Does that make sense?

What I have tried:

Heres what I have so far:

it('renders fixed value on  reservour parmeability selection and other parameter fields are hidden', async () => {
    const wrapper = mount(
      <RecoilRoot>
        <ReservoirTypeFieldset />
      </RecoilRoot>
    );
    await act(async () => {
      wrapper.find('select').at(0).prop('onChange')({
        currentTarget: { value: 'reservoir_permeability' },
      });
      wrapper.mount();
      wrapper.update();
    });
    expect(wrapper.find('fixedValue')).toHaveLength(1);
    expect(wrapper.find(' min')).toHaveLength(1);
  });
But I get this error:
 expect(received).toHaveLength(expected)
    Expected length: 1
    Received length: 0
    Received object: {}

Any help is much-appreciated thanks!