diff --git a/src/Illuminate/Foundation/Testing/Concerns/InteractsWithConsole.php b/src/Illuminate/Foundation/Testing/Concerns/InteractsWithConsole.php
index 382f2927120a..5e962e80a75d 100644
--- a/src/Illuminate/Foundation/Testing/Concerns/InteractsWithConsole.php
+++ b/src/Illuminate/Foundation/Testing/Concerns/InteractsWithConsole.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Foundation\Testing\Concerns;
 
+use Illuminate\Support\Arr;
 use Illuminate\Console\OutputStyle;
 use Illuminate\Contracts\Console\Kernel;
 use Illuminate\Foundation\Testing\PendingCommand;
@@ -44,11 +45,11 @@ public function artisan($command, $parameters = [])
 
         $this->beforeApplicationDestroyed(function () {
             if (count($this->expectedQuestions)) {
-                $this->fail('Question "'.array_first($this->expectedQuestions)[0].'" was not asked.');
+                $this->fail('Question "'.Arr::first($this->expectedQuestions)[0].'" was not asked.');
             }
 
             if (count($this->expectedOutput)) {
-                $this->fail('Output "'.array_first($this->expectedOutput).'" was not printed.');
+                $this->fail('Output "'.Arr::first($this->expectedOutput).'" was not printed.');
             }
         });
 
diff --git a/src/Illuminate/Support/helpers.php b/src/Illuminate/Support/helpers.php
index ba34e893973e..7bd92ec68cdb 100755
--- a/src/Illuminate/Support/helpers.php
+++ b/src/Illuminate/Support/helpers.php
@@ -38,6 +38,8 @@ function append_config(array $array)
      * @param  string  $key
      * @param  mixed   $value
      * @return array
+     *
+     * @deprecated Arr::add() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_add($array, $key, $value)
     {
@@ -51,6 +53,8 @@ function array_add($array, $key, $value)
      *
      * @param  array  $array
      * @return array
+     *
+     * @deprecated Arr::collapse() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_collapse($array)
     {
@@ -64,6 +68,8 @@ function array_collapse($array)
      *
      * @param  array  $array
      * @return array
+     *
+     * @deprecated Arr::divide() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_divide($array)
     {
@@ -78,6 +84,8 @@ function array_divide($array)
      * @param  array   $array
      * @param  string  $prepend
      * @return array
+     *
+     * @deprecated Arr::dot() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_dot($array, $prepend = '')
     {
@@ -92,6 +100,8 @@ function array_dot($array, $prepend = '')
      * @param  array  $array
      * @param  array|string  $keys
      * @return array
+     *
+     * @deprecated Arr::except() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_except($array, $keys)
     {
@@ -107,6 +117,8 @@ function array_except($array, $keys)
      * @param  callable|null  $callback
      * @param  mixed  $default
      * @return mixed
+     *
+     * @deprecated Arr::first() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_first($array, callable $callback = null, $default = null)
     {
@@ -121,6 +133,8 @@ function array_first($array, callable $callback = null, $default = null)
      * @param  array  $array
      * @param  int  $depth
      * @return array
+     *
+     * @deprecated Arr::flatten() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_flatten($array, $depth = INF)
     {
@@ -135,6 +149,8 @@ function array_flatten($array, $depth = INF)
      * @param  array  $array
      * @param  array|string  $keys
      * @return void
+     *
+     * @deprecated Arr::forget() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_forget(&$array, $keys)
     {
@@ -150,6 +166,8 @@ function array_forget(&$array, $keys)
      * @param  string  $key
      * @param  mixed   $default
      * @return mixed
+     *
+     * @deprecated Arr::get() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_get($array, $key, $default = null)
     {
@@ -164,6 +182,8 @@ function array_get($array, $key, $default = null)
      * @param  \ArrayAccess|array  $array
      * @param  string|array  $keys
      * @return bool
+     *
+     * @deprecated Arr::has() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_has($array, $keys)
     {
@@ -179,6 +199,8 @@ function array_has($array, $keys)
      * @param  callable|null  $callback
      * @param  mixed  $default
      * @return mixed
+     *
+     * @deprecated Arr::last() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_last($array, callable $callback = null, $default = null)
     {
@@ -193,6 +215,8 @@ function array_last($array, callable $callback = null, $default = null)
      * @param  array  $array
      * @param  array|string  $keys
      * @return array
+     *
+     * @deprecated Arr::only() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_only($array, $keys)
     {
@@ -208,6 +232,8 @@ function array_only($array, $keys)
      * @param  string|array  $value
      * @param  string|array|null  $key
      * @return array
+     *
+     * @deprecated Arr::pluck() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_pluck($array, $value, $key = null)
     {
@@ -223,6 +249,8 @@ function array_pluck($array, $value, $key = null)
      * @param  mixed  $value
      * @param  mixed  $key
      * @return array
+     *
+     * @deprecated Arr::prepend() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_prepend($array, $value, $key = null)
     {
@@ -238,6 +266,8 @@ function array_prepend($array, $value, $key = null)
      * @param  string  $key
      * @param  mixed   $default
      * @return mixed
+     *
+     * @deprecated Arr::pull() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_pull(&$array, $key, $default = null)
     {
@@ -252,6 +282,8 @@ function array_pull(&$array, $key, $default = null)
      * @param  array  $array
      * @param  int|null  $num
      * @return mixed
+     *
+     * @deprecated Arr::random() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_random($array, $num = null)
     {
@@ -269,6 +301,8 @@ function array_random($array, $num = null)
      * @param  string  $key
      * @param  mixed   $value
      * @return array
+     *
+     * @deprecated Arr::set() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_set(&$array, $key, $value)
     {
@@ -283,6 +317,8 @@ function array_set(&$array, $key, $value)
      * @param  array  $array
      * @param  callable|string|null  $callback
      * @return array
+     *
+     * @deprecated Arr::sort() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_sort($array, $callback = null)
     {
@@ -296,6 +332,8 @@ function array_sort($array, $callback = null)
      *
      * @param  array  $array
      * @return array
+     *
+     * @deprecated Arr::sortRecursive() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_sort_recursive($array)
     {
@@ -310,6 +348,8 @@ function array_sort_recursive($array)
      * @param  array  $array
      * @param  callable  $callback
      * @return array
+     *
+     * @deprecated Arr::where() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_where($array, callable $callback)
     {
@@ -323,6 +363,8 @@ function array_where($array, callable $callback)
      *
      * @param  mixed  $value
      * @return array
+     *
+     * @deprecated Arr::wrap() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function array_wrap($value)
     {
@@ -365,6 +407,8 @@ function blank($value)
      *
      * @param  string  $value
      * @return string
+     *
+     * @deprecated Str::camel() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function camel_case($value)
     {
@@ -572,6 +616,8 @@ function e($value, $doubleEncode = true)
      * @param  string  $haystack
      * @param  string|array  $needles
      * @return bool
+     *
+     * @deprecated Str::endsWith() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function ends_with($haystack, $needles)
     {
@@ -650,6 +696,8 @@ function head($array)
      *
      * @param  string  $value
      * @return string
+     *
+     * @deprecated Str::kebab() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function kebab_case($value)
     {
@@ -778,6 +826,8 @@ function retry($times, callable $callback, $sleep = 0)
      * @param  string  $value
      * @param  string  $delimiter
      * @return string
+     *
+     * @deprecated Str::snake() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function snake_case($value, $delimiter = '_')
     {
@@ -792,6 +842,8 @@ function snake_case($value, $delimiter = '_')
      * @param  string  $haystack
      * @param  string|array  $needles
      * @return bool
+     *
+     * @deprecated Str::startsWith() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function starts_with($haystack, $needles)
     {
@@ -806,6 +858,8 @@ function starts_with($haystack, $needles)
      * @param  string  $subject
      * @param  string  $search
      * @return string
+     *
+     * @deprecated Str::after() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_after($subject, $search)
     {
@@ -820,6 +874,8 @@ function str_after($subject, $search)
      * @param  string  $subject
      * @param  string  $search
      * @return string
+     *
+     * @deprecated Str::before() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_before($subject, $search)
     {
@@ -834,6 +890,8 @@ function str_before($subject, $search)
      * @param  string  $haystack
      * @param  string|array  $needles
      * @return bool
+     *
+     * @deprecated Str::contains() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_contains($haystack, $needles)
     {
@@ -848,6 +906,8 @@ function str_contains($haystack, $needles)
      * @param  string  $value
      * @param  string  $cap
      * @return string
+     *
+     * @deprecated Str::finish() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_finish($value, $cap)
     {
@@ -862,6 +922,8 @@ function str_finish($value, $cap)
      * @param  string|array  $pattern
      * @param  string  $value
      * @return bool
+     *
+     * @deprecated Str::is() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_is($pattern, $value)
     {
@@ -877,6 +939,8 @@ function str_is($pattern, $value)
      * @param  int     $limit
      * @param  string  $end
      * @return string
+     *
+     * @deprecated Str::limit() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_limit($value, $limit = 100, $end = '...')
     {
@@ -891,6 +955,8 @@ function str_limit($value, $limit = 100, $end = '...')
      * @param  string  $value
      * @param  int     $count
      * @return string
+     *
+     * @deprecated Str::plural() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_plural($value, $count = 2)
     {
@@ -906,6 +972,8 @@ function str_plural($value, $count = 2)
      * @return string
      *
      * @throws \RuntimeException
+     *
+     * @deprecated Str::random() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_random($length = 16)
     {
@@ -921,6 +989,8 @@ function str_random($length = 16)
      * @param  array   $replace
      * @param  string  $subject
      * @return string
+     *
+     * @deprecated Str::replaceArray() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_replace_array($search, array $replace, $subject)
     {
@@ -936,6 +1006,8 @@ function str_replace_array($search, array $replace, $subject)
      * @param  string  $replace
      * @param  string  $subject
      * @return string
+     *
+     * @deprecated Str::replaceFirst() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_replace_first($search, $replace, $subject)
     {
@@ -951,6 +1023,8 @@ function str_replace_first($search, $replace, $subject)
      * @param  string  $replace
      * @param  string  $subject
      * @return string
+     *
+     * @deprecated Str::replaceLast() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_replace_last($search, $replace, $subject)
     {
@@ -964,6 +1038,8 @@ function str_replace_last($search, $replace, $subject)
      *
      * @param  string  $value
      * @return string
+     *
+     * @deprecated Str::singular() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_singular($value)
     {
@@ -979,6 +1055,8 @@ function str_singular($value)
      * @param  string  $separator
      * @param  string  $language
      * @return string
+     *
+     * @deprecated Str::slug() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_slug($title, $separator = '-', $language = 'en')
     {
@@ -993,6 +1071,8 @@ function str_slug($title, $separator = '-', $language = 'en')
      * @param  string  $value
      * @param  string  $prefix
      * @return string
+     *
+     * @deprecated Str::start() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function str_start($value, $prefix)
     {
@@ -1006,6 +1086,8 @@ function str_start($value, $prefix)
      *
      * @param  string  $value
      * @return string
+     *
+     * @deprecated Str::studly() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function studly_case($value)
     {
@@ -1080,6 +1162,8 @@ function throw_unless($condition, $exception, ...$parameters)
      *
      * @param  string  $value
      * @return string
+     *
+     * @deprecated Str::title() should be used directly instead. Will be removed in Laravel 5.9.
      */
     function title_case($value)
     {
diff --git a/tests/Foundation/FoundationHelpersTest.php b/tests/Foundation/FoundationHelpersTest.php
index 001ce7d8c86a..29d03a4279d4 100644
--- a/tests/Foundation/FoundationHelpersTest.php
+++ b/tests/Foundation/FoundationHelpersTest.php
@@ -4,6 +4,7 @@
 
 use stdClass;
 use Mockery as m;
+use Illuminate\Support\Str;
 use Illuminate\Foundation\Mix;
 use PHPUnit\Framework\TestCase;
 use Illuminate\Foundation\Application;
@@ -210,7 +211,7 @@ protected function makeHotModuleReloadFile($url, $directory = '')
             return __DIR__;
         });
 
-        $path = public_path(str_finish($directory, '/').'hot');
+        $path = public_path(Str::finish($directory, '/').'hot');
 
         // Laravel mix when run 'hot' has a new line after the
         // url, so for consistency this "\n" is added.
@@ -225,7 +226,7 @@ protected function makeManifest($directory = '')
             return __DIR__;
         });
 
-        $path = public_path(str_finish($directory, '/').'mix-manifest.json');
+        $path = public_path(Str::finish($directory, '/').'mix-manifest.json');
 
         touch($path);
 
diff --git a/tests/Foundation/Http/Middleware/TransformsRequestTest.php b/tests/Foundation/Http/Middleware/TransformsRequestTest.php
index d2a43b18f7f4..76a45d831887 100644
--- a/tests/Foundation/Http/Middleware/TransformsRequestTest.php
+++ b/tests/Foundation/Http/Middleware/TransformsRequestTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Foundation\Http\Middleware;
 
+use Illuminate\Support\Str;
 use Illuminate\Http\Request;
 use PHPUnit\Framework\TestCase;
 use Illuminate\Foundation\Http\Middleware\TransformsRequest;
@@ -113,11 +114,11 @@ class ManipulateArrayInput extends TransformsRequest
 {
     protected function transform($key, $value)
     {
-        if (str_contains($key, 'beers')) {
+        if (Str::contains($key, 'beers')) {
             $value++;
         }
 
-        if (str_contains($key, 'age')) {
+        if (Str::contains($key, 'age')) {
             $value--;
         }
 
diff --git a/tests/Integration/Auth/AuthenticationTest.php b/tests/Integration/Auth/AuthenticationTest.php
index 72a5d40ac1af..83586f8afac6 100644
--- a/tests/Integration/Auth/AuthenticationTest.php
+++ b/tests/Integration/Auth/AuthenticationTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Auth;
 
+use Illuminate\Support\Str;
 use Illuminate\Auth\Events\Login;
 use Orchestra\Testbench\TestCase;
 use Illuminate\Auth\Events\Failed;
@@ -209,7 +210,7 @@ public function test_auth_via_attempt_remembering()
             'username' => 'username2',
             'email' => 'email2',
             'password' => bcrypt('password'),
-            'remember_token' => $token = str_random(),
+            'remember_token' => $token = Str::random(),
             'is_active' => false,
         ]);
 
diff --git a/tests/Integration/Database/EloquentBelongsToManyTest.php b/tests/Integration/Database/EloquentBelongsToManyTest.php
index aed50f04c574..7971b61c0339 100644
--- a/tests/Integration/Database/EloquentBelongsToManyTest.php
+++ b/tests/Integration/Database/EloquentBelongsToManyTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentBelongsToManyTest;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\DB;
 use Illuminate\Support\Facades\Schema;
@@ -45,11 +46,11 @@ public function test_basic_create_and_retrieve()
     {
         Carbon::setTestNow('2017-10-10 10:10:10');
 
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
-        $tag3 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
+        $tag3 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->sync([
             $tag->id => ['flag' => 'taylor'],
@@ -80,8 +81,8 @@ public function test_basic_create_and_retrieve()
 
     public function test_refresh_on_other_model_works()
     {
-        $post = Post::create(['title' => str_random()]);
-        $tag = Tag::create(['name' => $tagName = str_random()]);
+        $post = Post::create(['title' => Str::random()]);
+        $tag = Tag::create(['name' => $tagName = Str::random()]);
 
         $post->tags()->sync([
             $tag->id,
@@ -110,9 +111,9 @@ public function test_custom_pivot_class()
     {
         Carbon::setTestNow('2017-10-10 10:10:10');
 
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = TagWithCustomPivot::create(['name' => str_random()]);
+        $tag = TagWithCustomPivot::create(['name' => Str::random()]);
 
         $post->tagsWithCustomPivot()->attach($tag->id);
 
@@ -135,16 +136,16 @@ public function test_custom_pivot_class()
 
     public function test_attach_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
-        $tag3 = Tag::create(['name' => str_random()]);
-        $tag4 = Tag::create(['name' => str_random()]);
-        $tag5 = Tag::create(['name' => str_random()]);
-        $tag6 = Tag::create(['name' => str_random()]);
-        $tag7 = Tag::create(['name' => str_random()]);
-        $tag8 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
+        $tag3 = Tag::create(['name' => Str::random()]);
+        $tag4 = Tag::create(['name' => Str::random()]);
+        $tag5 = Tag::create(['name' => Str::random()]);
+        $tag6 = Tag::create(['name' => Str::random()]);
+        $tag7 = Tag::create(['name' => Str::random()]);
+        $tag8 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach($tag->id);
         $this->assertEquals($tag->name, $post->tags[0]->name);
@@ -175,15 +176,15 @@ public function test_attach_method()
 
     public function test_detach_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
-        $tag3 = Tag::create(['name' => str_random()]);
-        $tag4 = Tag::create(['name' => str_random()]);
-        $tag5 = Tag::create(['name' => str_random()]);
-        Tag::create(['name' => str_random()]);
-        Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
+        $tag3 = Tag::create(['name' => Str::random()]);
+        $tag4 = Tag::create(['name' => Str::random()]);
+        $tag5 = Tag::create(['name' => Str::random()]);
+        Tag::create(['name' => Str::random()]);
+        Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -218,9 +219,9 @@ public function test_detach_method()
 
     public function test_first_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -232,17 +233,17 @@ public function test_first_method()
      */
     public function test_firstOrFail_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         $post->tags()->firstOrFail(['id' => 10]);
     }
 
     public function test_find_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -255,9 +256,9 @@ public function test_find_method()
      */
     public function test_findOrFail_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        Tag::create(['name' => str_random()]);
+        Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -266,9 +267,9 @@ public function test_findOrFail_method()
 
     public function test_findOrNew_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -280,9 +281,9 @@ public function test_findOrNew_method()
 
     public function test_firstOrNew_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -294,9 +295,9 @@ public function test_firstOrNew_method()
 
     public function test_firstOrCreate_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -309,9 +310,9 @@ public function test_firstOrCreate_method()
 
     public function test_updateOrCreate_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
         $post->tags()->attach(Tag::all());
 
@@ -324,12 +325,12 @@ public function test_updateOrCreate_method()
 
     public function test_sync_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
-        $tag3 = Tag::create(['name' => str_random()]);
-        $tag4 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
+        $tag3 = Tag::create(['name' => Str::random()]);
+        $tag4 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->sync([$tag->id, $tag2->id]);
 
@@ -367,10 +368,10 @@ public function test_sync_method()
 
     public function test_syncWithoutDetaching_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->sync([$tag->id]);
 
@@ -389,10 +390,10 @@ public function test_syncWithoutDetaching_method()
 
     public function test_toggle_method()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = Tag::create(['name' => str_random()]);
-        $tag2 = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $tag2 = Tag::create(['name' => Str::random()]);
 
         $post->tags()->toggle([$tag->id]);
 
@@ -419,9 +420,9 @@ public function test_toggle_method()
 
     public function test_touching_parent()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = TouchingTag::create(['name' => str_random()]);
+        $tag = TouchingTag::create(['name' => Str::random()]);
 
         $post->touchingTags()->attach([$tag->id]);
 
@@ -432,15 +433,15 @@ public function test_touching_parent()
         $tag->update(['name' => $tag->name]);
         $this->assertNotEquals('2017-10-10 10:10:10', $post->fresh()->updated_at->toDateTimeString());
 
-        $tag->update(['name' => str_random()]);
+        $tag->update(['name' => Str::random()]);
         $this->assertEquals('2017-10-10 10:10:10', $post->fresh()->updated_at->toDateTimeString());
     }
 
     public function test_touching_related_models_on_sync()
     {
-        $tag = TouchingTag::create(['name' => str_random()]);
+        $tag = TouchingTag::create(['name' => Str::random()]);
 
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         $this->assertNotEquals('2017-10-10 10:10:10', $post->fresh()->updated_at->toDateTimeString());
         $this->assertNotEquals('2017-10-10 10:10:10', $tag->fresh()->updated_at->toDateTimeString());
@@ -455,9 +456,9 @@ public function test_touching_related_models_on_sync()
 
     public function test_no_touching_happens_if_not_configured()
     {
-        $tag = Tag::create(['name' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
 
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         $this->assertNotEquals('2017-10-10 10:10:10', $post->fresh()->updated_at->toDateTimeString());
         $this->assertNotEquals('2017-10-10 10:10:10', $tag->fresh()->updated_at->toDateTimeString());
@@ -472,11 +473,11 @@ public function test_no_touching_happens_if_not_configured()
 
     public function test_can_retrieve_related_ids()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('tags')->insert([
             ['id' => 200, 'name' => 'excluded'],
-            ['id' => 300, 'name' => str_random()],
+            ['id' => 300, 'name' => Str::random()],
         ]);
 
         DB::table('posts_tags')->insert([
@@ -490,11 +491,11 @@ public function test_can_retrieve_related_ids()
 
     public function test_can_touch_related_models()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('tags')->insert([
-            ['id' => 200, 'name' => str_random()],
-            ['id' => 300, 'name' => str_random()],
+            ['id' => 200, 'name' => Str::random()],
+            ['id' => 300, 'name' => Str::random()],
         ]);
 
         DB::table('posts_tags')->insert([
@@ -516,8 +517,8 @@ public function test_can_touch_related_models()
 
     public function test_can_update_existing_pivot()
     {
-        $tag = Tag::create(['name' => str_random()]);
-        $post = Post::create(['title' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('posts_tags')->insert([
             ['post_id' => $post->id, 'tag_id' => $tag->id, 'flag' => 'empty'],
@@ -533,10 +534,10 @@ public function test_can_update_existing_pivot()
     public function test_can_update_existing_pivot_using_arrayable_of_ids()
     {
         $tags = new Collection([
-            $tag1 = Tag::create(['name' => str_random()]),
-            $tag2 = Tag::create(['name' => str_random()]),
+            $tag1 = Tag::create(['name' => Str::random()]),
+            $tag2 = Tag::create(['name' => Str::random()]),
         ]);
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('posts_tags')->insert([
             ['post_id' => $post->id, 'tag_id' => $tag1->id, 'flag' => 'empty'],
@@ -552,8 +553,8 @@ public function test_can_update_existing_pivot_using_arrayable_of_ids()
 
     public function test_can_update_existing_pivot_using_model()
     {
-        $tag = Tag::create(['name' => str_random()]);
-        $post = Post::create(['title' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('posts_tags')->insert([
             ['post_id' => $post->id, 'tag_id' => $tag->id, 'flag' => 'empty'],
@@ -568,9 +569,9 @@ public function test_can_update_existing_pivot_using_model()
 
     public function test_custom_related_key()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
-        $tag = $post->tagsWithCustomRelatedKey()->create(['name' => str_random()]);
+        $tag = $post->tagsWithCustomRelatedKey()->create(['name' => Str::random()]);
         $this->assertEquals($tag->name, $post->tagsWithCustomRelatedKey()->first()->pivot->tag_id);
 
         $post->tagsWithCustomRelatedKey()->detach($tag);
@@ -589,8 +590,8 @@ public function test_custom_related_key()
 
     public function test_global_scope_columns()
     {
-        $tag = Tag::create(['name' => str_random()]);
-        $post = Post::create(['title' => str_random()]);
+        $tag = Tag::create(['name' => Str::random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         DB::table('posts_tags')->insert([
             ['post_id' => $post->id, 'tag_id' => $tag->id, 'flag' => 'empty'],
diff --git a/tests/Integration/Database/EloquentBelongsToTest.php b/tests/Integration/Database/EloquentBelongsToTest.php
index d68d31ffab09..fadfd2eea96c 100644
--- a/tests/Integration/Database/EloquentBelongsToTest.php
+++ b/tests/Integration/Database/EloquentBelongsToTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentBelongsToTest;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Tests\Integration\Database\DatabaseTestCase;
@@ -22,7 +23,7 @@ public function setUp()
             $table->string('parent_slug')->nullable();
         });
 
-        $user = User::create(['slug' => str_random()]);
+        $user = User::create(['slug' => Str::random()]);
         User::create(['parent_id' => $user->id, 'parent_slug' => $user->slug]);
     }
 
diff --git a/tests/Integration/Database/EloquentHasManyThroughTest.php b/tests/Integration/Database/EloquentHasManyThroughTest.php
index a1323ce1d740..6a91eb6556ec 100644
--- a/tests/Integration/Database/EloquentHasManyThroughTest.php
+++ b/tests/Integration/Database/EloquentHasManyThroughTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentHasManyThroughTest;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\SoftDeletes;
@@ -43,15 +44,15 @@ public function setUp()
 
     public function test_basic_create_and_retrieve()
     {
-        $user = User::create(['name' => str_random()]);
+        $user = User::create(['name' => Str::random()]);
 
         $team1 = Team::create(['id' => 10, 'owner_id' => $user->id]);
         $team2 = Team::create(['owner_id' => $user->id]);
 
-        $mate1 = User::create(['name' => str_random(), 'team_id' => $team1->id]);
-        $mate2 = User::create(['name' => str_random(), 'team_id' => $team2->id]);
+        $mate1 = User::create(['name' => Str::random(), 'team_id' => $team1->id]);
+        $mate2 = User::create(['name' => Str::random(), 'team_id' => $team2->id]);
 
-        User::create(['name' => str_random()]);
+        User::create(['name' => Str::random()]);
 
         $this->assertEquals([$mate1->id, $mate2->id], $user->teamMates->pluck('id')->toArray());
         $this->assertEquals([$user->id], User::has('teamMates')->pluck('id')->toArray());
@@ -59,11 +60,11 @@ public function test_basic_create_and_retrieve()
 
     public function test_global_scope_columns()
     {
-        $user = User::create(['name' => str_random()]);
+        $user = User::create(['name' => Str::random()]);
 
         $team1 = Team::create(['owner_id' => $user->id]);
 
-        User::create(['name' => str_random(), 'team_id' => $team1->id]);
+        User::create(['name' => Str::random(), 'team_id' => $team1->id]);
 
         $teamMates = $user->teamMatesWithGlobalScope;
 
@@ -72,11 +73,11 @@ public function test_global_scope_columns()
 
     public function test_has_self()
     {
-        $user = User::create(['name' => str_random()]);
+        $user = User::create(['name' => Str::random()]);
 
         $team = Team::create(['owner_id' => $user->id]);
 
-        User::create(['name' => str_random(), 'team_id' => $team->id]);
+        User::create(['name' => Str::random(), 'team_id' => $team->id]);
 
         $users = User::has('teamMates')->get();
 
@@ -85,11 +86,11 @@ public function test_has_self()
 
     public function test_has_self_custom_owner_key()
     {
-        $user = User::create(['slug' => str_random(), 'name' => str_random()]);
+        $user = User::create(['slug' => Str::random(), 'name' => Str::random()]);
 
         $team = Team::create(['owner_slug' => $user->slug]);
 
-        User::create(['name' => str_random(), 'team_id' => $team->id]);
+        User::create(['name' => Str::random(), 'team_id' => $team->id]);
 
         $users = User::has('teamMatesBySlug')->get();
 
diff --git a/tests/Integration/Database/EloquentModelConnectionsTest.php b/tests/Integration/Database/EloquentModelConnectionsTest.php
index fda43f3855b4..d03560a8209b 100644
--- a/tests/Integration/Database/EloquentModelConnectionsTest.php
+++ b/tests/Integration/Database/EloquentModelConnectionsTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database;
 
+use Illuminate\Support\Str;
 use Orchestra\Testbench\TestCase;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
@@ -59,14 +60,14 @@ public function setUp()
 
     public function test_child_obeys_parent_connection()
     {
-        $parent1 = ParentModel::create(['name' => str_random()]);
+        $parent1 = ParentModel::create(['name' => Str::random()]);
         $parent1->children()->create(['name' => 'childOnConn1']);
         $parents1 = ParentModel::with('children')->get();
         $this->assertEquals('childOnConn1', ChildModel::on('conn1')->first()->name);
         $this->assertEquals('childOnConn1', $parent1->children()->first()->name);
         $this->assertEquals('childOnConn1', $parents1[0]->children[0]->name);
 
-        $parent2 = ParentModel::on('conn2')->create(['name' => str_random()]);
+        $parent2 = ParentModel::on('conn2')->create(['name' => Str::random()]);
         $parent2->children()->create(['name' => 'childOnConn2']);
         $parents2 = ParentModel::on('conn2')->with('children')->get();
         $this->assertEquals('childOnConn2', ChildModel::on('conn2')->first()->name);
@@ -76,7 +77,7 @@ public function test_child_obeys_parent_connection()
 
     public function test_child_uses_its_own_connection_if_set()
     {
-        $parent1 = ParentModel::create(['name' => str_random()]);
+        $parent1 = ParentModel::create(['name' => Str::random()]);
         $parent1->childrenDefaultConn2()->create(['name' => 'childAlwaysOnConn2']);
         $parents1 = ParentModel::with('childrenDefaultConn2')->get();
         $this->assertEquals('childAlwaysOnConn2', ChildModelDefaultConn2::first()->name);
@@ -87,7 +88,7 @@ public function test_child_uses_its_own_connection_if_set()
 
     public function test_child_uses_its_own_connection_if_set_even_if_parent_explicit_connection()
     {
-        $parent1 = ParentModel::on('conn1')->create(['name' => str_random()]);
+        $parent1 = ParentModel::on('conn1')->create(['name' => Str::random()]);
         $parent1->childrenDefaultConn2()->create(['name' => 'childAlwaysOnConn2']);
         $parents1 = ParentModel::on('conn1')->with('childrenDefaultConn2')->get();
         $this->assertEquals('childAlwaysOnConn2', ChildModelDefaultConn2::first()->name);
diff --git a/tests/Integration/Database/EloquentModelTest.php b/tests/Integration/Database/EloquentModelTest.php
index 9c586186db31..67928edc5b0c 100644
--- a/tests/Integration/Database/EloquentModelTest.php
+++ b/tests/Integration/Database/EloquentModelTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
@@ -45,7 +46,7 @@ public function test_user_can_update_nullable_date()
     public function test_attribute_changes()
     {
         $user = TestModel2::create([
-            'name' => str_random(), 'title' => str_random(),
+            'name' => Str::random(), 'title' => Str::random(),
         ]);
 
         $this->assertEmpty($user->getDirty());
@@ -53,7 +54,7 @@ public function test_attribute_changes()
         $this->assertFalse($user->isDirty());
         $this->assertFalse($user->wasChanged());
 
-        $user->name = $name = str_random();
+        $user->name = $name = Str::random();
 
         $this->assertEquals(['name' => $name], $user->getDirty());
         $this->assertEmpty($user->getChanges());
diff --git a/tests/Integration/Database/EloquentMorphManyTest.php b/tests/Integration/Database/EloquentMorphManyTest.php
index b6989ca3296c..37aaf304a8de 100644
--- a/tests/Integration/Database/EloquentMorphManyTest.php
+++ b/tests/Integration/Database/EloquentMorphManyTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentMorphManyTest;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
@@ -35,7 +36,7 @@ public function setUp()
 
     public function test_update_model_with_default_withCount()
     {
-        $post = Post::create(['title' => str_random()]);
+        $post = Post::create(['title' => Str::random()]);
 
         $post->update(['title' => 'new name']);
 
diff --git a/tests/Integration/Database/EloquentTouchParentWithGlobalScopeTest.php b/tests/Integration/Database/EloquentTouchParentWithGlobalScopeTest.php
index 6c22212f953c..5ee60bcc02b7 100644
--- a/tests/Integration/Database/EloquentTouchParentWithGlobalScopeTest.php
+++ b/tests/Integration/Database/EloquentTouchParentWithGlobalScopeTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database\EloquentTouchParentWithGlobalScopeTest;
 
+use Illuminate\Support\Str;
 use Illuminate\Support\Carbon;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
@@ -34,11 +35,11 @@ public function setUp()
 
     public function test_basic_create_and_retrieve()
     {
-        $post = Post::create(['title' => str_random(), 'updated_at' => '2016-10-10 10:10:10']);
+        $post = Post::create(['title' => Str::random(), 'updated_at' => '2016-10-10 10:10:10']);
 
         $this->assertEquals('2016-10-10', $post->fresh()->updated_at->toDateString());
 
-        $post->comments()->create(['title' => str_random()]);
+        $post->comments()->create(['title' => Str::random()]);
 
         $this->assertNotEquals('2016-10-10', $post->fresh()->updated_at->toDateString());
     }
diff --git a/tests/Integration/Database/EloquentUpdateTest.php b/tests/Integration/Database/EloquentUpdateTest.php
index baf1712d20dc..5b05abbc3eea 100644
--- a/tests/Integration/Database/EloquentUpdateTest.php
+++ b/tests/Integration/Database/EloquentUpdateTest.php
@@ -2,6 +2,7 @@
 
 namespace Illuminate\Tests\Integration\Database;
 
+use Illuminate\Support\Str;
 use Orchestra\Testbench\TestCase;
 use Illuminate\Support\Facades\Schema;
 use Illuminate\Database\Eloquent\Model;
@@ -47,7 +48,7 @@ public function setUp()
     public function testBasicUpdate()
     {
         TestUpdateModel1::create([
-            'name' => str_random(),
+            'name' => Str::random(),
             'title' => 'Ms.',
         ]);
 
@@ -76,7 +77,7 @@ public function testUpdatedAtWithJoins()
         ]);
 
         TestUpdateModel2::create([
-            'name' => str_random(),
+            'name' => Str::random(),
         ]);
 
         TestUpdateModel2::join('test_model1', function ($join) {
@@ -92,12 +93,12 @@ public function testUpdatedAtWithJoins()
     public function testSoftDeleteWithJoins()
     {
         TestUpdateModel1::create([
-            'name' => str_random(),
+            'name' => Str::random(),
             'title' => 'Mr.',
         ]);
 
         TestUpdateModel2::create([
-            'name' => str_random(),
+            'name' => Str::random(),
         ]);
 
         TestUpdateModel2::join('test_model1', function ($join) {
diff --git a/tests/Integration/Foundation/FoundationHelpersTest.php b/tests/Integration/Foundation/FoundationHelpersTest.php
index 29c7354d8e56..a342b5a1bf5d 100644
--- a/tests/Integration/Foundation/FoundationHelpersTest.php
+++ b/tests/Integration/Foundation/FoundationHelpersTest.php
@@ -3,8 +3,8 @@
 namespace Illuminate\Tests\Integration\Foundation;
 
 use Exception;
+use Illuminate\Support\Str;
 use Orchestra\Testbench\TestCase;
-use Illuminate\Support\Facades\Route;
 use Illuminate\Contracts\Debug\ExceptionHandler;
 
 /**
@@ -107,7 +107,7 @@ protected function makeManifest($directory = '')
             return __DIR__;
         });
 
-        $path = public_path(str_finish($directory, '/').'mix-manifest.json');
+        $path = public_path(Str::finish($directory, '/').'mix-manifest.json');
 
         touch($path);
 
diff --git a/tests/Integration/Session/SessionPersistenceTest.php b/tests/Integration/Session/SessionPersistenceTest.php
index 38a06c5f7b0e..1ab66e45f22f 100644
--- a/tests/Integration/Session/SessionPersistenceTest.php
+++ b/tests/Integration/Session/SessionPersistenceTest.php
@@ -3,6 +3,7 @@
 namespace Illuminate\Tests\Integration\Session;
 
 use Mockery;
+use Illuminate\Support\Str;
 use Illuminate\Http\Response;
 use Orchestra\Testbench\TestCase;
 use Illuminate\Support\Facades\Route;
@@ -42,7 +43,7 @@ protected function getEnvironmentSetUp($app)
 
         $handler->shouldReceive('render')->andReturn(new Response);
 
-        $app['config']->set('app.key', str_random(32));
+        $app['config']->set('app.key', Str::random(32));
         $app['config']->set('session.driver', 'fake-null');
         $app['config']->set('session.expire_on_close', true);
     }
diff --git a/tests/Support/SupportHelpersTest.php b/tests/Support/SupportHelpersTest.php
index 79b0087a4a51..5f91f4fafcc5 100755
--- a/tests/Support/SupportHelpersTest.php
+++ b/tests/Support/SupportHelpersTest.php
@@ -270,9 +270,9 @@ public function testEndsWith()
 
     public function testStrAfter()
     {
-        $this->assertEquals('nah', str_after('hannah', 'han'));
-        $this->assertEquals('nah', str_after('hannah', 'n'));
-        $this->assertEquals('hannah', str_after('hannah', 'xxxx'));
+        $this->assertEquals('nah', Str::after('hannah', 'han'));
+        $this->assertEquals('nah', Str::after('hannah', 'n'));
+        $this->assertEquals('hannah', Str::after('hannah', 'xxxx'));
     }
 
     public function testStrContains()