diff --git a/CHANGELOG.md b/CHANGELOG.md
index c6e3ae8..15d2116 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ Common and useful classes, methods, exceptions etc.
 4. Travis CI > run many tasks using Phing (instead of PHPUnit only)
 5. Fix integration with [Coveralls](https://www.coveralls.io) (available as the badge in [README.md](README.md))
 6. Implement [PHPStan](https://github.com/phpstan/phpstan)
+7. PHPUnit > execute tests in random order
 
 # 1.0.1
 
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index a8faf74..b6e693d 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,11 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>
 
-<!-- https://phpunit.de/manual/4.8/en/appendixes.configuration.html -->
+<!-- https://phpunit.readthedocs.io/en/8.0/ -->
 <phpunit
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/4.8/phpunit.xsd"
         bootstrap="vendor/autoload.php"
         colors="true"
+        executionOrder="random"
         verbose="true"
 >
     <php>
diff --git a/tests/Collection/CollectionTest.php b/tests/Collection/CollectionTest.php
index 092ef89..5c5112a 100644
--- a/tests/Collection/CollectionTest.php
+++ b/tests/Collection/CollectionTest.php
@@ -347,27 +347,30 @@ class CollectionTest extends BaseTestCase
      */
     public function provideElementToAdd()
     {
-        $collection = new Collection();
-
         yield[
-            'test1',
+            'This is test 1',
             1,
             0,
-            $collection,
+            new Collection(),
         ];
 
         yield[
-            'test2',
+            'This is test 2',
             2,
             1,
-            $collection,
+            new Collection([
+                'I am 1st',
+            ]),
         ];
 
         yield[
-            'test3',
+            'This is test 3',
             3,
             2,
-            $collection,
+            new Collection([
+                'I am 1st',
+                'I am 2nd',
+            ]),
         ];
     }
 
@@ -378,46 +381,58 @@ class CollectionTest extends BaseTestCase
      */
     public function provideElementToAddWithIndex()
     {
-        $collection = new Collection();
-
         yield[
+            'This is test 1',
             'test1',
-            'aa',
             1,
-            'aa',
-            $collection,
+            'test1',
+            new Collection(),
         ];
 
         yield[
+            'This is test 2',
             'test2',
-            'oo',
             2,
-            'oo',
-            $collection,
+            'test2',
+            new Collection([
+                'test1' => 'I am 1st',
+            ]),
         ];
 
         yield[
-            'test3',
+            'This is test 3',
             null,
             3,
             0,
-            $collection,
+            new Collection([
+                'test1' => 'I am 1st',
+                'test2' => 'I am 2nd',
+            ]),
         ];
 
         yield[
-            'test4',
+            'This is test 4',
             '',
             4,
             1,
-            $collection,
+            new Collection([
+                'test1' => 'I am 1st',
+                'test2' => 'I am 2nd',
+                'I am 3rd',
+            ]),
         ];
 
         yield[
+            'This is test 5',
             'test5',
-            'vv',
             5,
-            'vv',
-            $collection,
+            'test5',
+            new Collection([
+                'test1' => 'I am 1st',
+                'test2' => 'I am 2nd',
+                2       => 'I am 3rd',
+                3       => 'I am 4th',
+            ]),
         ];
     }
 
diff --git a/tests/Utilities/UriTest.php b/tests/Utilities/UriTest.php
index 20b1eaf..6f92391 100644
--- a/tests/Utilities/UriTest.php
+++ b/tests/Utilities/UriTest.php
@@ -60,6 +60,15 @@ class UriTest extends BaseTestCase
      */
     public function testReplenishProtocol($expected, $url, $protocol = '')
     {
+        /*
+         * Required to get protocol when it's not provided and to void test failure:
+         *
+         * Failed asserting that two strings are identical.
+         * Expected :'://test'
+         * Actual   :'http://test'
+         */
+        $_SERVER['SERVER_PROTOCOL'] = 'HTTP/1.1';
+
         self::assertSame($expected, Uri::replenishProtocol($url, $protocol));
     }
 
@@ -251,7 +260,7 @@ class UriTest extends BaseTestCase
     public function provideUrlToReplenishProtocol()
     {
         yield[
-            '://test',
+            'http://test',
             'test',
             '',
         ];