diff --git a/src/app/features/markdown-render/markdown-render.component.ts b/src/app/features/markdown-render/markdown-render.component.ts
index 025e110e..f0e44e9e 100644
--- a/src/app/features/markdown-render/markdown-render.component.ts
+++ b/src/app/features/markdown-render/markdown-render.component.ts
@@ -13,7 +13,6 @@ import {
   ViewChild,
 } from '@angular/core';
 import { ActivatedRoute } from '@angular/router';
-import { ToolsetOption } from '@ledge-framework/render';
 import { Slugger } from 'marked/lib/marked';
 import { MarkdownService } from 'ngx-markdown';
 import Tocify, { TocItem } from './tocify';
diff --git a/src/app/presentation/case-study/case-study.component.ts b/src/app/presentation/case-study/case-study.component.ts
index 5409ac80..83ccadd8 100644
--- a/src/app/presentation/case-study/case-study.component.ts
+++ b/src/app/presentation/case-study/case-study.component.ts
@@ -11,7 +11,8 @@ import { MatDrawerContent } from '@angular/material/sidenav';
   styleUrls: ['./case-study.component.scss'],
 })
 export class CaseStudyComponent implements OnInit {
-  @ViewChild('drawerContent', {}) drawerContent: MatDrawerContent;
+  @ViewChild('drawerContent', { static: false })
+  drawerContent: MatDrawerContent;
 
   cases = [
     { displayName: '美团', source: 'meituan' },
@@ -98,8 +99,11 @@ export class CaseStudyComponent implements OnInit {
   }
 
   private resetScrollbar() {
-    if (this.drawerContent && this.drawerContent.getElementRef()) {
-      this.drawerContent.getElementRef().nativeElement.scrollTop = 0;
+    if (!!this.drawerContent) {
+      // on test drawerContent is different
+      if (!this.drawerContent.hasOwnProperty('nativeElement')) {
+        this.drawerContent.getElementRef().nativeElement.scrollTop = 0;
+      }
     }
   }
 
diff --git a/src/app/presentation/solution/solution.component.spec.ts b/src/app/presentation/solution/solution.component.spec.ts
index 89eb6bc7..d17fa78c 100644
--- a/src/app/presentation/solution/solution.component.spec.ts
+++ b/src/app/presentation/solution/solution.component.spec.ts
@@ -11,14 +11,14 @@ describe('SolutionComponent', () => {
   beforeEach(async(() => {
     TestBed.configureTestingModule({
       imports: [SharedModule, RouterTestingModule],
-      declarations: [SolutionComponent]
-    })
-      .compileComponents();
+      declarations: [SolutionComponent],
+    }).compileComponents();
   }));
 
   beforeEach(() => {
     fixture = TestBed.createComponent(SolutionComponent);
     component = fixture.componentInstance;
+    component.src = '';
     fixture.detectChanges();
   });
 
diff --git a/src/app/presentation/solution/solution.component.ts b/src/app/presentation/solution/solution.component.ts
index cbac0397..1ab97d68 100644
--- a/src/app/presentation/solution/solution.component.ts
+++ b/src/app/presentation/solution/solution.component.ts
@@ -11,7 +11,8 @@ import { MatDrawerContent } from '@angular/material/sidenav';
   styleUrls: ['./solution.component.scss'],
 })
 export class SolutionComponent implements OnInit {
-  @ViewChild('drawerContent', {}) drawerContent: MatDrawerContent;
+  @ViewChild('drawerContent', { static: false })
+  drawerContent: MatDrawerContent;
 
   solutions = [{ displayName: 'Coding', source: 'coding' }];
   currentSource: string;
@@ -78,8 +79,11 @@ export class SolutionComponent implements OnInit {
   }
 
   private resetScrollbar() {
-    if (this.drawerContent && this.drawerContent.getElementRef()) {
-      this.drawerContent.getElementRef().nativeElement.scrollTop = 0;
+    if (!!this.drawerContent) {
+      // on test drawerContent is different
+      if (!this.drawerContent.hasOwnProperty('nativeElement')) {
+        this.drawerContent.getElementRef().nativeElement.scrollTop = 0;
+      }
     }
   }