diff --git a/composer.json b/composer.json
index e051258..aed2087 100644
--- a/composer.json
+++ b/composer.json
@@ -34,7 +34,8 @@
   "autoload-dev": {
     "psr-4": {
       "Budgegeria\\IntlFormat\\Tests\\": "tests/"
-    }
+    },
+    "files": ["src/intl-format.php"]
   },
   "prefer-stable": true,
   "config": {
diff --git a/tests/FactoryTest.php b/tests/FactoryTest.php
index ff1ee62..944c294 100644
--- a/tests/FactoryTest.php
+++ b/tests/FactoryTest.php
@@ -9,8 +9,11 @@
 use DateTime;
 use DateTimeZone;
 use Exception;
+use Locale;
 use PHPUnit\Framework\TestCase;
 
+use function Budgegeria\IntlFormat\sprintf;
+
 class FactoryTest extends TestCase
 {
     public function testCreateIntlFormat(): void
@@ -40,4 +43,25 @@ public function testCreateIntlFormatIntegration(): void
         self::assertSame('Error: "test"', $intlFormat->format('Error: "%emessage"', new Exception('test')));
         self::assertSame('User Foo has 10 points', $intlFormat->format('User %s has %d points', 'Foo', 10));
     }
+
+    public function testSprintF(): void
+    {
+        Locale::setDefault('en_US');
+        $date = new DateTime();
+        $date->setDate(2016, 3, 1);
+        $date->setTime(5, 30);
+        $date->setTimezone(new DateTimeZone('US/Arizona'));
+
+        self::assertSame('Today is 3/1/16', sprintf('Today is %date_short', $date));
+        self::assertSame('I got 1,002.25 as average value', sprintf('I got %number as average value', 1002.25));
+        self::assertSame('I got 1,002.2500 as average value', sprintf('I got %.4number as average value', 1002.25));
+        self::assertSame('I got 01,002.2500 as average value', sprintf('I got %011.4number as average value', 1002.25));
+        self::assertSame('I got 1,002.3 as average value', sprintf('I got %.1number_halfway_up as average value', 1002.25));
+        self::assertSame('I is 5:30 AM on my clock.', sprintf('I is %time_short on my clock.', $date));
+        self::assertSame('The timezone id is US/Arizona.', sprintf('The timezone id is %timezone_id.', $date));
+        self::assertSame('I am from Italy.', sprintf('I am from %region.', 'it_IT'));
+        self::assertSame('You have 10$.', sprintf('You have 10%currency_symbol.', ''));
+        self::assertSame('Error: "test"', sprintf('Error: "%emessage"', new Exception('test')));
+        self::assertSame('User Foo has 10 points', sprintf('User %s has %d points', 'Foo', 10));
+    }
 }