Jest - Mock dispatch

index.test.tsx

const dispatch = jest.fn();
const state = { ... };

render(
  <SomeContext.Provider value={{ state, dispatch }}>
    <Component />
  </SomeContext.Provider>
);

// Call a button or somtheing
expect(dispatch).toHaveBeenCalled();
expect(dispatch).toHaveBeenCalledWith({
  payload: { value: 'N' },
  type: 'SOME/SET_SOME'
});