diff --git a/src/components/SqlEditor.vue b/src/components/SqlEditor.vue
index 8c826a0..22830c0 100644
--- a/src/components/SqlEditor.vue
+++ b/src/components/SqlEditor.vue
@@ -1,39 +1,22 @@
 <template>
   <div class="codemirror-container">
-    <codemirror v-model="query" :options="cmOptions" @changes="onCmChange" />
+    <codemirror v-model="query" :options="cmOptions" @changes="onChange" />
   </div>
 </template>
 
 <script>
-import CM from 'codemirror'
+import hint from '@/hint'
 import { codemirror } from 'vue-codemirror'
 import 'codemirror/lib/codemirror.css'
 import 'codemirror/mode/sql/sql.js'
 import 'codemirror/theme/neo.css'
-import 'codemirror/addon/hint/show-hint.js'
 import 'codemirror/addon/hint/show-hint.css'
-import 'codemirror/addon/hint/sql-hint.js'
 import 'codemirror/addon/display/autorefresh.js'
-import { debounce } from 'debounce'
-
-const sqlHint = CM.hint.sql
-CM.hint.sql = (cm, options) => {
-  const token = cm.getTokenAt(cm.getCursor()).string.toUpperCase()
-  const result = sqlHint(cm, options)
-  // Don't show the hint if there is only one option
-  // and the token is already completed with this option
-  if (result.list.length === 1 && result.list[0].text.toUpperCase() === token) {
-    result.list = []
-  }
-  return result
-}
 
 export default {
   name: 'SqlEditor',
   props: ['value'],
-  components: {
-    codemirror
-  },
+  components: { codemirror },
   data () {
     return {
       query: this.value,
@@ -49,40 +32,13 @@ export default {
       }
     }
   },
-  computed: {
-    tables () {
-      const tables = {}
-      if (this.$store.state.schema) {
-        this.$store.state.schema.forEach(table => {
-          tables[table.name] = table.columns.map(column => column.name)
-        })
-      }
-      return tables
-    }
-  },
   watch: {
     query () {
       this.$emit('input', this.query)
     }
   },
   methods: {
-    onCmChange: debounce(function (editor) {
-      // Don't show autocomplete after a space or semicolon or in string literals
-      const ch = editor.getTokenAt(editor.getCursor()).string.slice(-1)
-      const tokenType = editor.getTokenAt(editor.getCursor()).type
-      if (tokenType === 'string' || !ch || ch === ' ' || ch === ';') {
-        return
-      }
-
-      const hintOptions = {
-        tables: this.tables,
-        completeSingle: false,
-        completeOnSingleClick: true,
-        alignWithWord: false
-      }
-
-      CM.showHint(editor, CM.hint.sql, hintOptions)
-    }, 400)
+    onChange: hint.show
   }
 }
 </script>
diff --git a/src/hint.js b/src/hint.js
new file mode 100644
index 0000000..c584bb8
--- /dev/null
+++ b/src/hint.js
@@ -0,0 +1,45 @@
+import CM from 'codemirror'
+import 'codemirror/addon/hint/show-hint.js'
+import 'codemirror/addon/hint/sql-hint.js'
+import store from '@/store'
+import { debounce } from 'debounce'
+
+export function getHints (cm, options) {
+  const token = cm.getTokenAt(cm.getCursor()).string.toUpperCase()
+  const result = CM.hint.sql(cm, options)
+  // Don't show the hint if there is only one option
+  // and the token is already completed with this option
+  if (result.list.length === 1 && result.list[0].text.toUpperCase() === token) {
+    result.list = []
+  }
+  return result
+}
+
+const hintOptions = {
+  get tables () {
+    const tables = {}
+    if (store.state.schema) {
+      store.state.schema.forEach(table => {
+        tables[table.name] = table.columns.map(column => column.name)
+      })
+    }
+    return tables
+  },
+  completeSingle: false,
+  completeOnSingleClick: true,
+  alignWithWord: false
+}
+
+export default {
+  show: debounce(function (editor) {
+    // Don't show autocomplete after a space or semicolon or in string literals
+    const token = editor.getTokenAt(editor.getCursor())
+    const ch = token.string.slice(-1)
+    const tokenType = token.type
+    if (tokenType === 'string' || !ch || ch === ' ' || ch === ';') {
+      return
+    }
+
+    CM.showHint(editor, getHints, hintOptions)
+  }, 400)
+}
diff --git a/tests/unit/components/SqlEditor.spec.js b/tests/unit/components/SqlEditor.spec.js
new file mode 100644
index 0000000..43ea490
--- /dev/null
+++ b/tests/unit/components/SqlEditor.spec.js
@@ -0,0 +1,11 @@
+import { expect } from 'chai'
+import { mount } from '@vue/test-utils'
+import SqlEditor from '@/components/SqlEditor.vue'
+
+describe('SqlEditor.vue', () => {
+  it('Emits input event when a query is changed', async() => {
+    const wrapper = mount(SqlEditor)
+    await wrapper.findComponent({ name: 'codemirror'}).vm.$emit('input', 'SELECT * FROM foo')
+    expect(wrapper.emitted('input')[0]).to.eql(['SELECT * FROM foo'])
+  })
+})
diff --git a/tests/unit/hint.spec.js b/tests/unit/hint.spec.js
new file mode 100644
index 0000000..5525aee
--- /dev/null
+++ b/tests/unit/hint.spec.js
@@ -0,0 +1,205 @@
+import { expect } from 'chai'
+import sinon from 'sinon'
+import { state } from '@/store'
+import { default as hint, getHints } from '@/hint'
+import CM from 'codemirror'
+
+describe('hint.js', () => {
+  it('Calculates table list for hint', () => {
+    // mock store state
+    const schema = [
+        {
+          name: 'foo',
+          columns: [
+            { name: 'fooId', type: 'INTEGER' },
+            { name: 'name', type: 'NVARCHAR(20)' }
+          ]
+        },
+        {
+          name: 'bar',
+          columns: [
+            { name: 'barId', type: 'INTEGER' }
+          ]
+        }
+      ]
+    sinon.stub(state, 'schema').value(schema)
+
+    // mock showHint and editor
+    sinon.stub(CM, 'showHint')
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'SELECT',
+          type: 'keyword'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const clock = sinon.useFakeTimers();
+    hint.show(editor)
+    clock.tick(500)
+
+    expect(CM.showHint.called).to.equal(true)
+    expect(CM.showHint.firstCall.args[2].tables).to.eql({
+      foo: ['fooId', 'name'],
+      bar: ['barId']
+    })
+    
+    sinon.restore()
+  })
+
+  it("Doesn't show hint when in string or space, or ';'", () => {
+    // mock showHint and editor
+    sinon.stub(CM, 'showHint')
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'foo',
+          type: 'string'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const clock = sinon.useFakeTimers()
+    hint.show(editor)
+    clock.tick(500)
+    
+    expect(CM.showHint.called).to.equal(false)
+    
+    sinon.restore()
+  })
+
+  it("Doesn't show hint after space", () => {
+    // mock showHint and editor
+    sinon.stub(CM, 'showHint')
+    const editor = {
+      getTokenAt() {
+        return {
+          string: ' ',
+          type: null
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const clock = sinon.useFakeTimers()
+    hint.show(editor)
+    clock.tick(500)
+    
+    expect(CM.showHint.called).to.equal(false)
+    
+    sinon.restore()
+  })
+
+  it("Doesn't show hint after ';'", () => {
+    // mock showHint and editor
+    sinon.stub(CM, 'showHint')
+    const editor = {
+      getTokenAt() {
+        return {
+          string: ';',
+          type: 'punctuation'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const clock = sinon.useFakeTimers()
+    hint.show(editor)
+    clock.tick(500)
+    
+    expect(CM.showHint.called).to.equal(false)
+    
+    sinon.restore()
+  })
+
+  it("getHints returns [ ] if there is only one option and the token is already completed with this option", () => {
+    // mock CM.hint.sql and editor
+    sinon.stub(CM.hint, 'sql').returns({ list: [{ text: 'SELECT' }] })
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'select',
+          type: 'keyword'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const hints = getHints(editor, {})
+    expect(hints.list).to.eql([])
+    
+    sinon.restore()
+  })
+
+  it("getHints returns hints as is when there are more than one option", () => {
+    // mock CM.hint.sql and editor
+    let list = [
+      { text: 'SELECT' },
+      { text: 'ST' }
+    ]
+    sinon.stub(CM.hint, 'sql').returns({ list })
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'se',
+          type: 'keyword'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const hints = getHints(editor, {})
+    expect(hints.list).to.eql(list)
+    
+    sinon.restore()
+  })
+
+  it("getHints returns hints as is when there only one option but the token is not cpmpleted", () => {
+    // mock CM.hint.sql and editor
+    let list = [{ text: 'SELECT' }]
+    sinon.stub(CM.hint, 'sql').returns({ list })
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'sele',
+          type: 'keyword'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const hints = getHints(editor, {})
+    expect(hints.list).to.eql(list)
+    
+    sinon.restore()
+  })
+
+  it('tables is empty object when schema is null', () => {
+    // mock store state
+    sinon.stub(state, 'schema').value(null)
+
+    // mock showHint and editor
+    sinon.stub(CM, 'showHint')
+    const editor = {
+      getTokenAt() {
+        return {
+          string: 'SELECT',
+          type: 'keyword'
+        }
+      },
+      getCursor: sinon.stub()
+    }
+
+    const clock = sinon.useFakeTimers();
+    hint.show(editor)
+    clock.tick(500)
+
+    expect(CM.showHint.called).to.equal(true)
+    expect(CM.showHint.firstCall.args[2].tables).to.eql({})
+    
+    sinon.restore()
+  })
+})