improve code coverage on devTools.js

Author: ellbee

test/devTools.spec.js

@@ -14,6 +14,7 @@ function counterWithBug(state = 0, action) {
   switch (action.type) {
     case 'INCREMENT': return state + 1;
     case 'DECREMENT': return mistake - 1; // eslint-disable-line no-undef
+    case 'SET_UNDEFINED': return undefined;
     default: return state;
   }
 }
@@ -202,18 +203,13 @@ describe('devTools', () => {
     spy.restore();
   });
 
-  it('returns the last non-undefined state from getState', () => {
-    let spy = spyOn(console, 'error');
-
-    store.dispatch({ type: 'INCREMENT' });
-    store.dispatch({ type: 'DECREMENT' });
-    store.dispatch({ type: 'INCREMENT' });
-    store.dispatch({ type: 'INCREMENT' });
-    expect(store.getState()).toBe(2);
-
-    store.replaceReducer(counterWithBug);
-    expect(store.getState()).toBe(1);
+  it('should return the last non-undefined state from getState', () => {
+    let storeWithBug = devTools()(createStore)(counterWithBug);
+    storeWithBug.dispatch({ type: 'INCREMENT' });
+    storeWithBug.dispatch({ type: 'INCREMENT' });
+    expect(storeWithBug.getState()).toBe(2);
 
-    spy.restore();
+    storeWithBug.dispatch({ type: 'SET_UNDEFINED' });
+    expect(storeWithBug.getState()).toBe(2);
   });
 });