import { customersReducer } from './customers.reducer' ; import { customersInitialState } from './customers.state' ; describe ( 'Customers Reducer' , ( ) => { describe ( 'an unknown action' , ( ) => { it ( 'should return the previous state' , ( ) => { const action = { } as any ; const result = customersReducer ( customersInitialState , action ) ; expect ( result ) . toBe ( customersInitialState ) ; } ) ; } ) ; } ) ;