tests for reducer, including onStateChange tests

test/Input/ducks/Input.test.js

@@ -0,0 +1,53 @@
+import React from "react";
+import Input, {changeField, createBoundType} from "../../../src/Input/ducks/Input";
+import {createStore} from "redux";
+
+describe('Input duck', () => {
+  const namespace = 'test';
+  const actionType = createBoundType(namespace);
+
+  it('handles actions', () => {
+    const reducer = Input(namespace);
+    const store = createStore(reducer);
+    expect(store.getState()).toEqual({});
+
+    store.dispatch(changeField(actionType, 'testInput', 'testValue'));
+    const expectedState = {testInput: 'testValue'};
+    expect(store.getState()).toEqual(expectedState);
+  });
+
+  it('calls onStateChange with the new state if the attribute is set', () => {
+    const mockOnStateChange = jest.fn(state => state);
+    const reducer = Input(namespace, {}, mockOnStateChange);
+    const store = createStore(reducer);
+    expect(store.getState()).toEqual({});
+
+    store.dispatch(changeField(actionType, 'testInput', 'testValue'));
+    const expectedState = {testInput: 'testValue'};
+    expect(store.getState()).toEqual(expectedState);
+    expect(mockOnStateChange).toHaveBeenCalledTimes(1);
+    expect(mockOnStateChange).toHaveBeenCalledWith(expectedState);
+  });
+
+  it('applies the state returned from onStateChange', () => {
+    const mockOnStateChange = jest.fn(state => ({
+      ...state,
+      ...(state.expectedPropWasPassed && {valueSetReactivelyToExpectedStateChange: true}),
+    }));
+    const reducer = Input(namespace, {}, mockOnStateChange);
+    const store = createStore(reducer);
+    expect(store.getState()).toEqual({});
+
+    store.dispatch(changeField(actionType, 'UNexpectedPropWasPassed', true));
+    expect(store.getState()).toEqual({UNexpectedPropWasPassed: true});
+
+    store.dispatch(changeField(actionType, 'expectedPropWasPassed', true));
+    expect(mockOnStateChange).toHaveBeenCalledTimes(2);
+    expect(mockOnStateChange).toHaveBeenLastCalledWith({UNexpectedPropWasPassed: true, expectedPropWasPassed: true});
+    expect(store.getState()).toEqual({
+      expectedPropWasPassed: true,
+      UNexpectedPropWasPassed: true,
+      valueSetReactivelyToExpectedStateChange: true,
+    });
+  });
+});