diff --git a/docs/src/components/page-header.vue b/docs/src/components/page-header.vue
index c61b15fdd..901c4e78e 100644
--- a/docs/src/components/page-header.vue
+++ b/docs/src/components/page-header.vue
@@ -51,7 +51,7 @@ export default {
     window.addEventListener('scroll', () => {
       clearTimeout(timer);
       const scrollTop = document.body.scrollTop || document.documentElement.scrollTop;
-      let timer = setTimeout(() => {
+      timer = setTimeout(() => {
         _this.scrollTop = scrollTop;
       }, 500);
     });
diff --git a/package.json b/package.json
index 5ea301b81..7ef2b5063 100644
--- a/package.json
+++ b/package.json
@@ -69,6 +69,7 @@
     "cp-cli": "^1.0.2",
     "cross-env": "^3.1.3",
     "css-loader": "^0.24.0",
+    "eslint-loader": "^1.7.1",
     "extract-text-webpack-plugin": "^2.0.0-beta.5",
     "felint": "^0.5.0-alpha.3",
     "file-loader": "^0.9.0",
diff --git a/test/unit/specs/quantity.spec.js b/test/unit/specs/quantity.spec.js
index 1a77ade48..43168f6d9 100644
--- a/test/unit/specs/quantity.spec.js
+++ b/test/unit/specs/quantity.spec.js
@@ -9,8 +9,108 @@ describe('Quantity', () => {
   });
 
   it('create a quantity', () => {
-    wrapper = mount(Quantity);
+    wrapper = mount(Quantity, {
+      propsData: {
+        defaultValue: 1
+      }
+    });
 
     expect(wrapper.hasClass('zan-quantity')).to.be.true;
+    expect(wrapper.data().currentValue).to.equal(1);
+
+    const plusButton = wrapper.find('.zan-quantity__plus')[0];
+    plusButton.simulate('click');
+
+    expect(wrapper.data().currentValue).to.equal(2);
+
+    const minusButton = wrapper.find('.zan-quantity__minus')[0];
+    minusButton.simulate('click');
+    expect(wrapper.data().currentValue).to.equal(1);
+  });
+
+  it('create a disabled quantity', (done) => {
+    wrapper = mount(Quantity, {
+      propsData: {
+        disabled: true
+      }
+    });
+
+    expect(wrapper.hasClass('zan-quantity')).to.be.true;
+    const minusButton = wrapper.find('.zan-quantity__minus')[0];
+    expect(minusButton.hasClass('zan-quantity__minus--disabled')).to.be.true;
+
+    const eventStub = sinon.stub(wrapper.vm, '$emit');
+    minusButton.simulate('click');
+
+    wrapper.update();
+    wrapper.vm.$nextTick(() => {
+      expect(eventStub.calledWith('overlimit'));
+      done();
+    });
+
+    const plusButton = wrapper.find('.zan-quantity__plus')[0];
+    expect(plusButton.hasClass('zan-quantity__plus--disabled')).to.be.true;
+
+    plusButton.simulate('click');
+
+    wrapper.update();
+    wrapper.vm.$nextTick(() => {
+      expect(eventStub.calledWith('overlimit'));
+      done();
+    });
+  });
+
+  it('update quantity value use v-model', (done) => {
+    wrapper = mount(Quantity, {
+      propsData: {
+        value: 1
+      }
+    });
+
+    expect(wrapper.hasClass('zan-quantity')).to.be.true;
+    const eventStub = sinon.stub(wrapper.vm, '$emit');
+
+    wrapper.vm.value = 2;
+    wrapper.update();
+    wrapper.vm.$nextTick(() => {
+      expect(eventStub.calledWith('input'));
+      expect(eventStub.calledWith('change'));
+      done();
+    });
+  });
+
+  it('correct value when value is not correct', (done) => {
+    wrapper = mount(Quantity, {
+      propsData: {
+        value: 50,
+        max: 30
+      }
+    });
+
+    expect(wrapper.hasClass('zan-quantity')).to.be.true;
+    const eventStub = sinon.stub(wrapper.vm, '$emit');
+    wrapper.update();
+    wrapper.vm.$nextTick(() => {
+      expect(eventStub.calledWith('input'));
+      done();
+    });
+  });
+
+  it('handle when input change', (done) => {
+    wrapper = mount(Quantity, {
+      propsData: {
+        value: 1
+      }
+    });
+
+    const input = wrapper.find('.zan-quantity__input')[0];
+    input.element.value = 2;
+    input.simulate('input');
+
+    wrapper.update();
+    wrapper.vm.$nextTick(() => {
+      expect(wrapper.data().currentValue).to.equal(2);
+      done();
+    });
   });
 });