diff --git a/src/storedQueries.js b/src/storedQueries.js
index f290bfd..4eacc15 100644
--- a/src/storedQueries.js
+++ b/src/storedQueries.js
@@ -73,7 +73,7 @@ export default {
 
     // Create downloader
     const downloader = document.createElement('a')
-    downloader.style.display = 'none'
+    downloader.hidden = true
     document.body.appendChild(downloader)
 
     // Prepare data
@@ -106,7 +106,7 @@ export default {
       uploader.id = 'file-uploader'
       uploader.type = 'file'
       uploader.accept = '.json'
-      uploader.style.display = 'none'
+      uploader.hidden = true
 
       uploader.addEventListener('change', () => {
         const file = uploader.files[0]
diff --git a/tests/unit/storedQueries.spec.js b/tests/unit/storedQueries.spec.js
new file mode 100644
index 0000000..4ebebcf
--- /dev/null
+++ b/tests/unit/storedQueries.spec.js
@@ -0,0 +1,44 @@
+import { expect } from 'chai'
+import storedQueries from '@/storedQueries.js'
+
+describe('storedQueries.js', () => {
+  beforeEach(()=> {
+    localStorage.removeItem('myQueries')
+  })
+
+  it('getStoredQueries(empty storage)', () => {
+    const queries = storedQueries.getStoredQueries() 
+    expect(queries).to.eql([])
+  })  
+
+  it('getStoredQueries', () => {
+    const data = [
+      { id: 1 },
+      { id: 2 },
+    ]
+    storedQueries.updateStorage(data)
+    const queries = storedQueries.getStoredQueries() 
+    expect(queries).to.eql(data)
+  })  
+
+  it('duplicateQuery', () => {
+    const now = new Date()
+    const nowPlusMinute = new Date(now.getTime() + 60*1000)
+    const base = {
+      id: 1,
+      name: 'foo',
+      query: 'SELECT * from foo',
+      chart: [],
+      createdAt: new Date(2021, 0, 1),
+      isPredefined: true   
+    }
+
+    const copy = storedQueries.duplicateQuery(base)
+    expect(copy).to.have.property('id').which.not.equal(base.id)
+    expect(copy).to.have.property('name').which.equal(base.name + ' Copy')
+    expect(copy).to.have.property('query').which.equal(base.query)
+    expect(copy).to.have.property('chart').which.eql(base.chart)
+    expect(copy).to.have.property('createdAt').which.within(now, nowPlusMinute)
+    expect(copy).to.not.have.property('isPredefined')
+  })
+})
\ No newline at end of file