diff --git a/tests/lib/html-text-helper-test.js b/tests/lib/html-text-helper-test.js
new file mode 100644
index 00000000..c61b3d16
--- /dev/null
+++ b/tests/lib/html-text-helper-test.js
@@ -0,0 +1,52 @@
+/**
+ * @fileoverview Unit test for browser/lib/htmlTextHelper
+ */
+const test = require('ava')
+const htmlTextHelper = require('browser/lib/htmlTextHelper')
+
+// Unit test
+test('htmlTextHelper#decodeEntities should return encoded text (string)', t => {
+  // [input, expected]
+  const testCases = [
+    ['&lt;a href=', '<a href='],
+    ['var test = &apos;test&apos;', "var test = 'test'"],
+    ['&lt;a href=&apos;https://boostnote.io&apos;&gt;Boostnote', "<a href='https://boostnote.io'>Boostnote"],
+    ["&lt;\\?php\n var = &apos;hoge&apos;;", "<\\?php\n var = 'hoge';"],
+    ["&amp;", "&"],
+  ]
+
+  testCases.forEach(testCase => {
+    const [input, expected] = testCase;
+    t.is(htmlTextHelper.decodeEntities(input), expected, `Test for decodeEntities() input: ${input} expected: ${expected}`);
+  })
+})
+
+test('htmlTextHelper#decodeEntities() should return decoded text (string)', t => {
+  // [input, expected]
+  const testCases = [
+    ['<a href=', '&lt;a href='],
+    ["var test = 'test'", 'var test = &apos;test&apos;'],
+    ["<a href='https://boostnote.io'>Boostnote", '&lt;a href=&apos;https://boostnote.io&apos;&gt;Boostnote'],
+    ["<?php\n var = 'hoge';", "&lt;&#63;php\n var = &apos;hoge&apos;;"],
+  ]
+
+  testCases.forEach(testCase => {
+    const [input, expected] = testCase;
+    t.is(htmlTextHelper.encodeEntities(input), expected, `Test for encodeEntities() input: ${input} expected: ${expected}`);
+  })
+})
+
+// Integration test
+test(t => {
+  const testCases = [
+    "var test = 'test'",
+    "<a href='https://boostnote.io'>Boostnote",
+    "<Component styleName='test' />",
+  ]
+
+  testCases.forEach(testCase => {
+    const encodedText = htmlTextHelper.encodeEntities(testCase)
+    const decodedText = htmlTextHelper.decodeEntities(encodedText)
+    t.is(decodedText, testCase, `Integration test for encodedText() and decodedText()`);
+  })
+})