diff --git a/tests/helpers/cookie-utils.spec.js b/tests/helpers/cookie-utils.spec.js
new file mode 100644
index 00000000..d1eaf255
--- /dev/null
+++ b/tests/helpers/cookie-utils.spec.js
@@ -0,0 +1,76 @@
+import { concatCookieNameValuePath } from '../../src/helpers/cookie-utils';
+
+describe('concatCookieNameValuePath', () => {
+    describe('encode cookie value', () => {
+        test.each([
+            {
+                actual: ['name', 'value', ''],
+                expected: 'name=value;',
+            },
+            {
+                actual: ['name', 'value', '/'],
+                expected: 'name=value; path=/',
+            },
+            {
+                actual: ['pop::138', '138', ''],
+                // do not encode cookie name
+                // https://github.com/AdguardTeam/Scriptlets/issues/408
+                expected: 'pop::138=138;',
+            },
+            {
+                actual: ['aa::bb::cc', '1', ''],
+                expected: 'aa::bb::cc=1;',
+            },
+            // invalid path
+            {
+                actual: ['name', 'value', '/docs'],
+                // no path is set if unsupported path values passed
+                expected: 'name=value;',
+            },
+            // invalid name because of ';'
+            {
+                actual: ['a;bc', 'def', ''],
+                expected: null,
+            },
+            // value with ';' but it should be encoded so its ok
+            {
+                actual: ['abc', 'de;f', ''],
+                expected: 'abc=de%3Bf;',
+            },
+        ])('$actual -> $expected', ({ actual, expected }) => {
+            expect(concatCookieNameValuePath(...actual)).toBe(expected);
+        });
+    });
+
+    describe('no cookie value encoding', () => {
+        test.each([
+            {
+                actual: ['name', 'value', ''],
+                expected: 'name=value;',
+            },
+            {
+                actual: ['aa::bb::cc', '1', ''],
+                expected: 'aa::bb::cc=1;',
+            },
+            {
+                actual: ['__w_cc11', '{%22cookies_statistical%22:false%2C%22cookies_ad%22:true}', ''],
+                // do not encode cookie value
+                // https://github.com/AdguardTeam/Scriptlets/issues/311
+                expected: '__w_cc11={%22cookies_statistical%22:false%2C%22cookies_ad%22:true};',
+            },
+            // invalid name because of ';'
+            {
+                actual: ['a;bc', 'def', ''],
+                expected: null,
+            },
+            // invalid value because of ';' and it is not being encoded
+            {
+                actual: ['abc', 'de;f', ''],
+                expected: null,
+            },
+        ])('$actual -> $expected', ({ actual, expected }) => {
+            // explicit 'false' to disable encoding
+            expect(concatCookieNameValuePath(...actual, false)).toBe(expected);
+        });
+    });
+});