diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index f7a5a0b..9852101 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -14,7 +14,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        php-version: [ '8.3', '8.4' ]
+        php-version: [ '8.3', '8.4', '8.5' ]
 
     name: Tests on PHP ${{ matrix.php-version }}
 
diff --git a/composer.json b/composer.json
index e09cc3b..8075b2c 100644
--- a/composer.json
+++ b/composer.json
@@ -18,7 +18,7 @@
     }
   ],
   "require": {
-    "php": "^8.3",
+    "php": ">=8.3 <8.6",
     "phpdocumentor/reflection-docblock": "^5.6",
     "psr/container": "^2.0"
   },
diff --git a/src/Container/Enum/Locales.php b/src/Container/Enum/Locales.php
new file mode 100644
index 0000000..7c1926c
--- /dev/null
+++ b/src/Container/Enum/Locales.php
@@ -0,0 +1,8 @@
+<?php
+
+namespace Xefi\Faker\Container\Enum;
+
+class Locales
+{
+    public const string DEFAULT = 'default';
+}
diff --git a/src/Container/Traits/HasExtensions.php b/src/Container/Traits/HasExtensions.php
index 254f4f2..475691b 100644
--- a/src/Container/Traits/HasExtensions.php
+++ b/src/Container/Traits/HasExtensions.php
@@ -4,6 +4,7 @@
 
 use Random\Randomizer;
 use Xefi\Faker\Container\Container;
+use Xefi\Faker\Container\Enum\Locales;
 use Xefi\Faker\Exceptions\NoExtensionLocaleFound;
 use Xefi\Faker\Extensions\Extension;
 
@@ -189,10 +190,10 @@ public function callExtensionMethod(string $method, array $parameters = [])
         // We assume we here have multiple extensions declined by locale, we will try
         // to get the extension with the current locale, defaulting to first element
         if (is_array($extension) && isset($extension['locales'])) {
-            if (!isset($extension['locales'][$this->getLocale()]) && !isset($extension['locales'][null])) {
-                throw new NoExtensionLocaleFound(sprintf('Locale \'%s\' and \'null\' for method \'%s\' was not found', $this->getLocale(), $method));
+            if (!isset($extension['locales'][$this->getLocale()]) && !isset($extension['locales'][Locales::DEFAULT])) {
+                throw new NoExtensionLocaleFound(sprintf('Locale \'%s\' and \'%s\' for method \'%s\' was not found', $this->getLocale(), Locales::DEFAULT, $method));
             }
-            $extension = $extension['locales'][$this->getLocale()] ?? $extension['locales'][null];
+            $extension = $extension['locales'][$this->getLocale()] ?? $extension['locales'][Locales::DEFAULT];
         }
 
         return $extension->$method(...$parameters);
diff --git a/src/Container/Traits/HasLocale.php b/src/Container/Traits/HasLocale.php
index 3fddf6f..6d0d323 100644
--- a/src/Container/Traits/HasLocale.php
+++ b/src/Container/Traits/HasLocale.php
@@ -2,6 +2,8 @@
 
 namespace Xefi\Faker\Container\Traits;
 
+use Xefi\Faker\Container\Enum\Locales;
+
 trait HasLocale
 {
     /**
@@ -18,7 +20,7 @@ trait HasLocale
      */
     public function getLocale(): ?string
     {
-        return $this->locale ?? null;
+        return $this->locale ?? Locales::DEFAULT;
     }
 
     /**
diff --git a/src/Extensions/Traits/HasLocale.php b/src/Extensions/Traits/HasLocale.php
index a5c2349..bcd1146 100644
--- a/src/Extensions/Traits/HasLocale.php
+++ b/src/Extensions/Traits/HasLocale.php
@@ -2,6 +2,8 @@
 
 namespace Xefi\Faker\Extensions\Traits;
 
+use Xefi\Faker\Container\Enum\Locales;
+
 trait HasLocale
 {
     /**
@@ -11,6 +13,6 @@ trait HasLocale
      */
     public function getLocale(): ?string
     {
-        return null;
+        return Locales::DEFAULT;
     }
 }
diff --git a/tests/Unit/Extensions/NumbersExtensionTest.php b/tests/Unit/Extensions/NumbersExtensionTest.php
index 0a245a4..8de48e8 100644
--- a/tests/Unit/Extensions/NumbersExtensionTest.php
+++ b/tests/Unit/Extensions/NumbersExtensionTest.php
@@ -71,7 +71,7 @@ public static function floatProvider()
             [-0.0001, 0.0001, 6],
             [1.111, 1.119, 4],
             [2500.0, 5000.0, 0],
-            [-0.999, 0.999, 2],
+            [-0.995, 0.995, 2],
             [1234.567, 2345.678, 3],
             [-300.3, -100.1, 1],
             [0.000001, 0.000009, 7],
diff --git a/tests/Unit/LocaleTest.php b/tests/Unit/LocaleTest.php
index 36196a4..b256a67 100644
--- a/tests/Unit/LocaleTest.php
+++ b/tests/Unit/LocaleTest.php
@@ -19,10 +19,10 @@ public function testExtensionsCorrectlyRegistered()
         $this->assertEquals(
             [
                 'locales' => [
-                    null    => new \Xefi\Faker\Tests\Support\Extensions\NullLocaleExtensionTest(new \Random\Randomizer()),
-                    'en_EN' => new \Xefi\Faker\Tests\Support\Extensions\EnEnExtensionTest(new \Random\Randomizer()),
-                    'en_US' => new \Xefi\Faker\Tests\Support\Extensions\EnUsExtensionTest(new \Random\Randomizer()),
-                    'fr_FR' => new \Xefi\Faker\Tests\Support\Extensions\FrFrExtensionTest(new \Random\Randomizer()),
+                    'default' => new \Xefi\Faker\Tests\Support\Extensions\NullLocaleExtensionTest(new \Random\Randomizer()),
+                    'en_EN'   => new \Xefi\Faker\Tests\Support\Extensions\EnEnExtensionTest(new \Random\Randomizer()),
+                    'en_US'   => new \Xefi\Faker\Tests\Support\Extensions\EnUsExtensionTest(new \Random\Randomizer()),
+                    'fr_FR'   => new \Xefi\Faker\Tests\Support\Extensions\FrFrExtensionTest(new \Random\Randomizer()),
                 ],
             ],
             (new \Xefi\Faker\Container\Container())->getExtensions()['locale-extension-test']
@@ -32,7 +32,7 @@ public function testExtensionsCorrectlyRegistered()
     public function testCallingDefaultExtension()
     {
         $this->assertEquals(
-            null,
+            'default',
             (new \Xefi\Faker\Faker())->returnLocale()
         );
     }
@@ -75,16 +75,21 @@ public function testResettingLocale()
         );
 
         $this->assertEquals(
-            null,
+            'default',
             $faker->locale(null)->returnLocale()
         );
+
+        $this->assertEquals(
+            'default',
+            $faker->locale('default')->returnLocale()
+        );
     }
 
     public function testUsingNotExistingLocaleFallingBackToNullLocale()
     {
         $faker = new Xefi\Faker\Faker('not-existing-locale');
         $this->assertEquals(
-            null,
+            'default',
             $faker->returnLocale()
         );
     }
@@ -101,7 +106,7 @@ public function testUsingNotExistingLocaleWithoutNullLocale()
         ]);
 
         $this->expectException(\Xefi\Faker\Exceptions\NoExtensionLocaleFound::class);
-        $this->expectExceptionMessage('Locale \'not-existing-locale\' and \'null\' for method \'returnLocale\' was not found');
+        $this->expectExceptionMessage('Locale \'not-existing-locale\' and \'default\' for method \'returnLocale\' was not found');
 
         $faker = new Xefi\Faker\Faker('not-existing-locale');
         $faker->returnLocale();