Enzyme/Jest React Testing - Shallow connected component with react-redux > 6

Question

We use Enzyme and Jest for testing. Updated to the latest version of react-redux in our code base, and all of the connected component test cases started failing (Version 6). Using

import { createMockStore } from 'redux-test-utils';

to create store

Test cases that worked with older version:

const wrapper = shallow(<SomeConnectedComponent />, {context: { store }});

This fails giving error

Invariant Violation: Could not find "store" in the context of "Connect(SomeConnectedComponent )".

Reading few posts, got a suggestion to mount and wrap with provider wrapper

const wrapper = mount(<Provider store={store}><SomeConnectedComponent /></Provider>);

Above code works, but I want it to work with swallow for unit testing.

Edit :

const wrapper = shallow(<Provider store={store}>
<SomeConnectedComponent />
</Provider>)

Above code returns empty shallowWraper object.

What is the best way to swallow connected component with react-redux version > 6

Answer 1

shallow does work on redux 7 but the implementation changed. so instead of

const wrapper = shallow(<Provider store={store <SomeConnectedComponent/></Provider>)

you now do

const wrapper = shallow(<SomeConnectedComponent store={store}/>)

Wrapping in a provider is no longer necessary and prevents unnecessary dives. You are then able to traverse the shallow wrapper like so:

wrapper.children().dive().find(<ChildComponent>))

Answer 2

Shallow does not work with the latest version of react-redux. From Version 6.x, it causes the mentioned problem.

The best solution I found was to use a older version of react-redux for testing, and the newer one for actual code.

1) Add the older version as a dev dependency. Because a newer version of react-redux is there you will need to use a alias. This can be any version 5.x This will install "react-redux-test"

yarn add react-redux-test@npm:[email protected] -D

2) Under the _ mocks _ folder, create a new file react-redux.js and export the older version from within

export * from 'react-redux-test';

This mock will be used in every test case file by default, so the old testing code no longer breaks.

If however you want to test with the new react-redux library, you can use

jest.unmock('react-redux')

above the new test file.

After upgrading there were hundreds of tests failing, this approach works for me as i want to use the Hooks Api in new components as well.

This way you can use features the new library until enzyme / react-redux come up with a fix.