diff --git a/README.md b/README.md
index 1f7e85d..164d37a 100644
--- a/README.md
+++ b/README.md
@@ -236,6 +236,22 @@ DateTimeHumanizer::preciseDifference(new \DateTime("2014-04-26 13:00:00"), new \
 DateTimeHumanizer::preciseDifference(new \DateTime("2014-04-26 13:00:00"), new \DateTime("2016-04-27 13:00:00")); // 2 years, 1 day from now
 ```
 
+## Aeon Calendar 
+
+[Aeon PHP](https://aeon-php.org/) is a date&time oriented set of libraries. 
+
+```php
+use Coduo\PHPHumanizer\DateTimeHumanizer;
+
+$timeUnit = TimeUnit::days(2)
+                ->add(TimeUnit::hours(3))
+                ->add(TimeUnit::minutes(25))
+                ->add(TimeUnit::seconds(30))
+                ->add(TimeUnit::milliseconds(200));
+            
+DateTimeHumanizer::timeUnit($timeUnit); // 2 days, 3 hours, 25 minutes, and 30.2 seconds
+```
+
 Currently we support following languages:
 * [Azerbaijani](src/Coduo/PHPHumanizer/Resources/translations/difference.az.yml)
 * [English](src/Coduo/PHPHumanizer/Resources/translations/difference.en.yml)
diff --git a/composer.json b/composer.json
index 58f5108..92dbc7a 100644
--- a/composer.json
+++ b/composer.json
@@ -17,7 +17,8 @@
     "require": {
         "php": "^7.4 | ^8.0",
         "symfony/translation": "^4.4|^5.0",
-        "symfony/yaml": "^4.4|^5.0"
+        "symfony/yaml": "^4.4|^5.0",
+        "aeon-php/calendar": ">=0.16.1"
     },
     "require-dev": {
         "thunderer/shortcode": "^0.7",
@@ -40,6 +41,10 @@
         "ext-intl": "Required if you are going to use humanizer with locales different than en_EN"
     },
     "scripts": {
+        "build": [
+            "@static:analyze",
+            "@test"
+        ],
         "cs:php:fix": [
             "tools/php-cs-fixer fix --using-cache=no"
         ],
diff --git a/composer.lock b/composer.lock
index d0fe9ed..1753b0c 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,63 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "2266b8e08228e1596ce0366b445cd246",
+    "content-hash": "c74a1cca580ca33e81761900ec3f88f1",
     "packages": [
+        {
+            "name": "aeon-php/calendar",
+            "version": "0.16.1",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/aeon-php/calendar.git",
+                "reference": "9509656c6b01024aad6158628fc8c950f9cf1199"
+            },
+            "dist": {
+                "type": "zip",
+                "url": "https://api.github.com/repos/aeon-php/calendar/zipball/9509656c6b01024aad6158628fc8c950f9cf1199",
+                "reference": "9509656c6b01024aad6158628fc8c950f9cf1199",
+                "shasum": ""
+            },
+            "require": {
+                "php": ">=7.4.2"
+            },
+            "require-dev": {
+                "ext-bcmath": "*"
+            },
+            "suggest": {
+                "ext-bcmath": "Compare time units with high precision"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "Aeon\\": [
+                        "src/Aeon"
+                    ]
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "PHP type safe, immutable calendar library",
+            "keywords": [
+                "calendar",
+                "date",
+                "datetime",
+                "immutable",
+                "time"
+            ],
+            "support": {
+                "issues": "https://github.com/aeon-php/calendar/issues",
+                "source": "https://github.com/aeon-php/calendar/tree/0.16.1"
+            },
+            "funding": [
+                {
+                    "url": "https://github.com/norberttech",
+                    "type": "github"
+                }
+            ],
+            "time": "2021-02-23T08:58:57+00:00"
+        },
         {
             "name": "symfony/deprecation-contracts",
             "version": "v2.2.0",
@@ -808,16 +863,16 @@
         },
         {
             "name": "phar-io/version",
-            "version": "3.0.4",
+            "version": "3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/phar-io/version.git",
-                "reference": "e4782611070e50613683d2b9a57730e9a3ba5451"
+                "reference": "bae7c545bef187884426f042434e561ab1ddb182"
             },
             "dist": {
                 "type": "zip",
-                "url": "https://api.github.com/repos/phar-io/version/zipball/e4782611070e50613683d2b9a57730e9a3ba5451",
-                "reference": "e4782611070e50613683d2b9a57730e9a3ba5451",
+                "url": "https://api.github.com/repos/phar-io/version/zipball/bae7c545bef187884426f042434e561ab1ddb182",
+                "reference": "bae7c545bef187884426f042434e561ab1ddb182",
                 "shasum": ""
             },
             "require": {
@@ -853,9 +908,9 @@
             "description": "Library for handling version information and constraints",
             "support": {
                 "issues": "https://github.com/phar-io/version/issues",
-                "source": "https://github.com/phar-io/version/tree/3.0.4"
+                "source": "https://github.com/phar-io/version/tree/3.1.0"
             },
-            "time": "2020-12-13T23:18:30+00:00"
+            "time": "2021-02-23T14:00:09+00:00"
         },
         {
             "name": "phpdocumentor/reflection-common",
diff --git a/src/Coduo/PHPHumanizer/Aeon/Calendar/Formatter.php b/src/Coduo/PHPHumanizer/Aeon/Calendar/Formatter.php
new file mode 100644
index 0000000..3576da6
--- /dev/null
+++ b/src/Coduo/PHPHumanizer/Aeon/Calendar/Formatter.php
@@ -0,0 +1,42 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the PHP Humanizer Library.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Coduo\PHPHumanizer\Aeon\Calendar;
+
+use Aeon\Calendar\Unit;
+use Coduo\PHPHumanizer\CollectionHumanizer;
+use Symfony\Contracts\Translation\TranslatorInterface;
+
+final class Formatter
+{
+    private TranslatorInterface $translator;
+
+    public function __construct(TranslatorInterface $translator)
+    {
+        $this->translator = $translator;
+    }
+
+    public function timeUnit(Unit $unit, string $locale = 'en') : string
+    {
+        $parts = [];
+
+        foreach ((new UnitCompound($unit))->components() as $component) {
+            $parts[] = $this->translator->trans(
+                'compound.'.$component->getUnit()->getName(),
+                ['%count%' => $component->getQuantity()],
+                'difference',
+                $locale
+            );
+        }
+
+        return CollectionHumanizer::oxford($parts, null, $locale);
+    }
+}
diff --git a/src/Coduo/PHPHumanizer/Aeon/Calendar/UnitCompound.php b/src/Coduo/PHPHumanizer/Aeon/Calendar/UnitCompound.php
new file mode 100644
index 0000000..b461b11
--- /dev/null
+++ b/src/Coduo/PHPHumanizer/Aeon/Calendar/UnitCompound.php
@@ -0,0 +1,83 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the PHP Humanizer Library.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Coduo\PHPHumanizer\Aeon\Calendar;
+
+use Aeon\Calendar\RelativeTimeUnit;
+use Aeon\Calendar\TimeUnit;
+use Aeon\Calendar\Unit;
+use Coduo\PHPHumanizer\DateTime\DateIntervalCompound;
+use Coduo\PHPHumanizer\DateTime\Difference\CompoundResult;
+use Coduo\PHPHumanizer\DateTime\Unit\Day;
+use Coduo\PHPHumanizer\DateTime\Unit\Hour;
+use Coduo\PHPHumanizer\DateTime\Unit\Minute;
+use Coduo\PHPHumanizer\DateTime\Unit\Month;
+use Coduo\PHPHumanizer\DateTime\Unit\Second;
+use Coduo\PHPHumanizer\DateTime\Unit\Year;
+
+final class UnitCompound
+{
+    private Unit $unit;
+
+    public function __construct(Unit $timeUnit)
+    {
+        $this->unit = $timeUnit;
+    }
+
+    /**
+     * @return array<CompoundResult>
+     */
+    public function components() : array
+    {
+        $unit = $this->unit;
+        $compoundResults = [];
+
+        if ($unit instanceof RelativeTimeUnit) {
+            if ($unit->inYears()) {
+                $compoundResults[] = new CompoundResult(new Year(), $unit->inYears());
+            }
+
+            if ($unit->inCalendarMonths()) {
+                $compoundResults[] = new CompoundResult(new Month(), $unit->inCalendarMonths());
+            }
+
+            return (new DateIntervalCompound($unit->toDateInterval()))->components();
+        }
+
+        if ($unit instanceof TimeUnit) {
+            if ($unit->inDaysAbs() > 0) {
+                $compoundResults[] = new CompoundResult(new Day(), $unit->inDaysAbs());
+            }
+
+            if ($unit->inTimeHours()) {
+                $compoundResults[] = new CompoundResult(new Hour(), $unit->inTimeHours());
+            }
+
+            if ($unit->inTimeMinutes()) {
+                $compoundResults[] = new CompoundResult(new Minute(), $unit->inTimeMinutes());
+            }
+
+            if ($unit->inTimeSeconds()) {
+                $seconds = $unit->inTimeSeconds();
+
+                if ($unit->inTimeMilliseconds() > 0) {
+                    $seconds += $unit->inTimeMilliseconds() / 1000;
+                }
+
+                $compoundResults[] = new CompoundResult(new Second(), $seconds);
+            }
+
+            return $compoundResults;
+        }
+
+        throw new \RuntimeException('Unsupported unit type ' . \get_class($unit));
+    }
+}
diff --git a/src/Coduo/PHPHumanizer/DateTime/DateIntervalCompound.php b/src/Coduo/PHPHumanizer/DateTime/DateIntervalCompound.php
new file mode 100644
index 0000000..c94c7d9
--- /dev/null
+++ b/src/Coduo/PHPHumanizer/DateTime/DateIntervalCompound.php
@@ -0,0 +1,58 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the PHP Humanizer Library.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Coduo\PHPHumanizer\DateTime;
+
+use Coduo\PHPHumanizer\DateTime\Difference\CompoundResult;
+use Coduo\PHPHumanizer\DateTime\Unit\Day;
+use Coduo\PHPHumanizer\DateTime\Unit\Hour;
+use Coduo\PHPHumanizer\DateTime\Unit\Minute;
+use Coduo\PHPHumanizer\DateTime\Unit\Month;
+use Coduo\PHPHumanizer\DateTime\Unit\Second;
+use Coduo\PHPHumanizer\DateTime\Unit\Year;
+
+final class DateIntervalCompound
+{
+    private \DateInterval $dateInterval;
+
+    public function __construct(\DateInterval $dateInterval)
+    {
+        $this->dateInterval = $dateInterval;
+    }
+
+    /**
+     * @return array<CompoundResult>
+     */
+    public function components() : array
+    {
+        /* @var Unit[] $units */
+        $units = [
+            new Year(),
+            new Month(),
+            new Day(),
+            new Hour(),
+            new Minute(),
+            new Second(),
+        ];
+
+
+        /** @var array<CompoundResult> $compoundResults */
+        $compoundResults = [];
+
+        foreach ($units as $unit) {
+            if ($this->dateInterval->{$unit->getDateIntervalSymbol()} > 0) {
+                $compoundResults[] = new CompoundResult($unit, (int) $this->dateInterval->{$unit->getDateIntervalSymbol()});
+            }
+        }
+
+        return $compoundResults;
+    }
+}
diff --git a/src/Coduo/PHPHumanizer/DateTime/Difference.php b/src/Coduo/PHPHumanizer/DateTime/Difference.php
index 2ca8258..25f8025 100644
--- a/src/Coduo/PHPHumanizer/DateTime/Difference.php
+++ b/src/Coduo/PHPHumanizer/DateTime/Difference.php
@@ -22,9 +22,9 @@
 
 final class Difference
 {
-    private \DateTime $fromDate;
+    private \DateTimeInterface $fromDate;
 
-    private \DateTime $toDate;
+    private \DateTimeInterface $toDate;
 
     /**
      * @psalm-suppress PropertyNotSetInConstructor
@@ -33,7 +33,7 @@ final class Difference
 
     private ?int $quantity = null;
 
-    public function __construct(\DateTime $fromDate, \DateTime $toDate)
+    public function __construct(\DateTimeInterface $fromDate, \DateTimeInterface $toDate)
     {
         $this->fromDate = $fromDate;
         $this->toDate = $toDate;
diff --git a/src/Coduo/PHPHumanizer/DateTime/Difference/CompoundResult.php b/src/Coduo/PHPHumanizer/DateTime/Difference/CompoundResult.php
index 512fd1b..7cedcbb 100644
--- a/src/Coduo/PHPHumanizer/DateTime/Difference/CompoundResult.php
+++ b/src/Coduo/PHPHumanizer/DateTime/Difference/CompoundResult.php
@@ -16,29 +16,29 @@
 final class CompoundResult
 {
     private Unit $unit;
-    private int $quantity;
 
-    public function __construct(Unit $unit, int $quantity)
-    {
-        $this->unit = $unit;
-        $this->quantity = $quantity;
-    }
+    /**
+     * @var int|float
+     */
+    private $quantity;
 
-    public function setQuantity(int $quantity): void
+    /**
+     * @param int|float $quantity
+     */
+    public function __construct(Unit $unit, $quantity)
     {
+        $this->unit = $unit;
         $this->quantity = $quantity;
     }
 
-    public function getQuantity() : int
+    /**
+     * @return int|float
+     */
+    public function getQuantity()
     {
         return $this->quantity;
     }
 
-    public function setUnit(Unit $unit): void
-    {
-        $this->unit = $unit;
-    }
-
     public function getUnit(): Unit
     {
         return $this->unit;
diff --git a/src/Coduo/PHPHumanizer/DateTime/PreciseDifference.php b/src/Coduo/PHPHumanizer/DateTime/PreciseDifference.php
index 0a75a80..c16f59e 100644
--- a/src/Coduo/PHPHumanizer/DateTime/PreciseDifference.php
+++ b/src/Coduo/PHPHumanizer/DateTime/PreciseDifference.php
@@ -11,65 +11,33 @@
 
 namespace Coduo\PHPHumanizer\DateTime;
 
-use Coduo\PHPHumanizer\DateTime\Unit\Day;
-use Coduo\PHPHumanizer\DateTime\Unit\Hour;
-use Coduo\PHPHumanizer\DateTime\Unit\Minute;
-use Coduo\PHPHumanizer\DateTime\Unit\Month;
-use Coduo\PHPHumanizer\DateTime\Unit\Second;
-use Coduo\PHPHumanizer\DateTime\Unit\Year;
 use Coduo\PHPHumanizer\DateTime\Difference\CompoundResult;
 
 final class PreciseDifference
 {
-    private \DateTime $fromDate;
+    private \DateTimeInterface $fromDate;
 
-    private \DateTime $toDate;
+    private \DateTimeInterface $toDate;
 
-    /**
-     * @var array<Unit>
-     */
-    private array $units = [];
-
-    /**
-     * @var array<CompoundResult>
-     */
-    private array $compoundResults = [];
+    private ?DateIntervalCompound $compoundResults ;
 
-    public function __construct(\DateTime $fromDate, \DateTime $toDate)
+    public function __construct(\DateTimeInterface $fromDate, \DateTimeInterface $toDate)
     {
         $this->fromDate = $fromDate;
         $this->toDate = $toDate;
-        $this->calculate();
+        $this->compoundResults = null;
     }
 
     /**
      * @return array<CompoundResult>
      */
-    public function getCompoundResults(): array
+    public function components() : array
     {
-        return $this->compoundResults;
-    }
-
-    private function calculate(): void
-    {
-        /* @var $units Unit[] */
-        $units = [
-            new Year(),
-            new Month(),
-            new Day(),
-            new Hour(),
-            new Minute(),
-            new Second(),
-        ];
-
-        $diff = $this->fromDate->diff($this->toDate);
-
-        foreach ($units as $unit) {
-            if ($diff->{$unit->getDateIntervalSymbol()} > 0) {
-                $this->units[] = $unit;
-                $this->compoundResults[] = new CompoundResult($unit, $diff->{$unit->getDateIntervalSymbol()});
-            }
+        if ($this->compoundResults === null) {
+            $this->compoundResults = new DateIntervalCompound($this->fromDate->diff($this->toDate));
         }
+
+        return $this->compoundResults->components();
     }
 
     public function isPast(): bool
diff --git a/src/Coduo/PHPHumanizer/DateTime/PreciseFormatter.php b/src/Coduo/PHPHumanizer/DateTime/PreciseFormatter.php
index 2036fb9..45a1f7f 100644
--- a/src/Coduo/PHPHumanizer/DateTime/PreciseFormatter.php
+++ b/src/Coduo/PHPHumanizer/DateTime/PreciseFormatter.php
@@ -11,6 +11,7 @@
 
 namespace Coduo\PHPHumanizer\DateTime;
 
+use Coduo\PHPHumanizer\CollectionHumanizer;
 use Symfony\Contracts\Translation\TranslatorInterface;
 
 final class PreciseFormatter
@@ -26,7 +27,7 @@ public function formatDifference(PreciseDifference $difference, string $locale =
     {
         $diff = [];
 
-        foreach ($difference->getCompoundResults() as $result) {
+        foreach ($difference->components() as $result) {
             $diff[] = $this->translator->trans(
                 'compound.'.$result->getUnit()->getName(),
                 ['%count%' => $result->getQuantity()],
@@ -42,4 +43,20 @@ public function formatDifference(PreciseDifference $difference, string $locale =
             $locale
         );
     }
+
+    public function formatInterval(\DateInterval $dateInterval, string $locale = 'en') : string
+    {
+        $parts = [];
+
+        foreach ((new DateIntervalCompound($dateInterval))->components() as $component) {
+            $parts[] = $this->translator->trans(
+                'compound.'.$component->getUnit()->getName(),
+                ['%count%' => $component->getQuantity()],
+                'difference',
+                $locale
+            );
+        }
+
+        return CollectionHumanizer::oxford($parts, null, $locale);
+    }
 }
diff --git a/src/Coduo/PHPHumanizer/DateTimeHumanizer.php b/src/Coduo/PHPHumanizer/DateTimeHumanizer.php
index 2c51cf5..2e6951d 100644
--- a/src/Coduo/PHPHumanizer/DateTimeHumanizer.php
+++ b/src/Coduo/PHPHumanizer/DateTimeHumanizer.php
@@ -11,6 +11,8 @@
 
 namespace Coduo\PHPHumanizer;
 
+use Aeon\Calendar\Gregorian\TimePeriod;
+use Aeon\Calendar\Unit;
 use Coduo\PHPHumanizer\DateTime\Difference;
 use Coduo\PHPHumanizer\DateTime\PreciseDifference;
 use Coduo\PHPHumanizer\DateTime\Formatter;
@@ -19,17 +21,38 @@
 
 final class DateTimeHumanizer
 {
-    public static function difference(\DateTime $fromDate, \DateTime $toDate, string $locale = 'en'): string
+    public static function difference(\DateTimeInterface $fromDate, \DateTimeInterface $toDate, string $locale = 'en'): string
     {
         $formatter = new Formatter(Builder::build($locale));
 
         return $formatter->formatDifference(new Difference($fromDate, $toDate), $locale);
     }
 
-    public static function preciseDifference(\DateTime $fromDate, \DateTime $toDate, string $locale = 'en'): string
+    public static function preciseDifference(\DateTimeInterface $fromDate, \DateTimeInterface $toDate, string $locale = 'en'): string
     {
         $formatter = new PreciseFormatter(Builder::build($locale));
 
         return $formatter->formatDifference(new PreciseDifference($fromDate, $toDate), $locale);
     }
+
+    public static function timeUnit(Unit $unit, string $locale = 'en') : string
+    {
+        $formatter = new Aeon\Calendar\Formatter(Builder::build($locale));
+
+        return $formatter->timeUnit($unit, $locale);
+    }
+
+    public static function timePeriod(TimePeriod $timePeriod, string $locale = 'en') : string
+    {
+        $formatter = new Formatter(Builder::build($locale));
+
+        return $formatter->formatDifference(new Difference($timePeriod->start()->toDateTimeImmutable(), $timePeriod->end()->toDateTimeImmutable()), $locale);
+    }
+
+    public static function timePeriodPrecise(TimePeriod $timePeriod, string $locale = 'en') : string
+    {
+        $formatter = new PreciseFormatter(Builder::build($locale));
+
+        return $formatter->formatDifference(new PreciseDifference($timePeriod->start()->toDateTimeImmutable(), $timePeriod->end()->toDateTimeImmutable()), $locale);
+    }
 }
diff --git a/tests/Coduo/PHPHumanizer/Tests/Aeon/Calendar/FormatterTest.php b/tests/Coduo/PHPHumanizer/Tests/Aeon/Calendar/FormatterTest.php
new file mode 100644
index 0000000..dca4d01
--- /dev/null
+++ b/tests/Coduo/PHPHumanizer/Tests/Aeon/Calendar/FormatterTest.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the PHP Humanizer Library.
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Coduo\PHPHumanizer\Tests\Aeon\Calendar;
+
+use Aeon\Calendar\RelativeTimeUnit;
+use Aeon\Calendar\TimeUnit;
+use Coduo\PHPHumanizer\Aeon\Calendar\Formatter;
+use Coduo\PHPHumanizer\Translator\Builder;
+use PHPUnit\Framework\TestCase;
+
+final class FormatterTest extends TestCase
+{
+    public function test_format_complex_time_unit() : void
+    {
+        $timeUnit = TimeUnit::days(2)
+            ->add(TimeUnit::hours(3))
+            ->add(TimeUnit::minutes(25))
+            ->add(TimeUnit::seconds(30))
+            ->add(TimeUnit::milliseconds(200));
+
+        $formatter = new Formatter(Builder::build('en'));
+
+        $this->assertSame(
+            '2 days, 3 hours, 25 minutes, and 30.2 seconds',
+            $formatter->timeUnit($timeUnit)
+        );
+    }
+
+    public function test_format_relative_time_unit() : void
+    {
+        $timeUnit = RelativeTimeUnit::months(14);
+
+        $formatter = new Formatter(Builder::build('en'));
+
+        $this->assertSame(
+            '1 year and 2 months',
+            $formatter->timeUnit($timeUnit)
+        );
+    }
+}
diff --git a/tests/Coduo/PHPHumanizer/Tests/DateTime/PreciseFormatterTest.php b/tests/Coduo/PHPHumanizer/Tests/DateTime/PreciseFormatterTest.php
index a14cb81..99b1c11 100644
--- a/tests/Coduo/PHPHumanizer/Tests/DateTime/PreciseFormatterTest.php
+++ b/tests/Coduo/PHPHumanizer/Tests/DateTime/PreciseFormatterTest.php
@@ -41,4 +41,16 @@ public function test_format_compound_datetime_diff_for_specific_locale()
 
         $this->assertSame('через 10 дней, 5 часов', $formatter->formatDifference($diff, 'ru'));
     }
+
+    public function test_format_date_interval() : void
+    {
+        $interval = new \DateInterval('P1DT5H25M43S');
+
+        $formatter = new PreciseFormatter(Builder::build('en'));
+
+        $this->assertSame(
+            '1 day, 5 hours, 25 minutes, and 43 seconds',
+            $formatter->formatInterval($interval)
+        );
+    }
 }
diff --git a/tests/Coduo/PHPHumanizer/Tests/DateTimeHumanizerTest.php b/tests/Coduo/PHPHumanizer/Tests/DateTimeHumanizerTest.php
index a4c441e..23ce537 100644
--- a/tests/Coduo/PHPHumanizer/Tests/DateTimeHumanizerTest.php
+++ b/tests/Coduo/PHPHumanizer/Tests/DateTimeHumanizerTest.php
@@ -11,42 +11,57 @@
 
 namespace Coduo\PHPHumanizer\Tests;
 
+use Aeon\Calendar\Gregorian\DateTime;
+use Aeon\Calendar\Gregorian\TimePeriod;
+use Aeon\Calendar\RelativeTimeUnit;
+use Aeon\Calendar\TimeUnit;
+use Aeon\Calendar\Unit;
 use Coduo\PHPHumanizer\DateTimeHumanizer;
 use PHPUnit\Framework\TestCase;
 
 class DateTimeHumanizerTest extends TestCase
 {
     /**
-     * @test
      * @dataProvider humanizeDataProvider
-     *
-     * @param        $firstDate
-     * @param        $secondDate
-     * @param        $expected
-     * @param string $locale
      */
-    public function test_humanize_difference_between_dates($firstDate, $secondDate, $expected, $locale)
+    public function test_humanize_difference_between_dates(string $firstDate, string $secondDate, string $expected, string $locale) : void
     {
         $this->assertEquals($expected, DateTimeHumanizer::difference(new \DateTime($firstDate), new \DateTime($secondDate), $locale));
     }
 
+    /**
+     * @dataProvider humanizeDataProvider
+     */
+    public function test_humanize_time_period(string $firstDate, string $secondDate, string $expected, string $locale) : void
+    {
+        $this->assertEquals($expected, DateTimeHumanizer::timePeriod(new TimePeriod(DateTime::fromString($firstDate), DateTime::fromString($secondDate)), $locale));
+    }
+
     /**
      * @dataProvider preciseDifferenceDataProvider
-     *
-     * @param        $firstDate
-     * @param        $secondDate
-     * @param        $expected
-     * @param string $locale
      */
-    public function test_humanize_precise_difference_between_dates($firstDate, $secondDate, $expected, $locale)
+    public function test_humanize_precise_difference_between_dates(string $firstDate, string $secondDate, string $expected, string $locale) : void
+    {
+        $this->assertEquals($expected, DateTimeHumanizer::timePeriodPrecise(new TimePeriod(DateTime::fromString($firstDate), DateTime::fromString($secondDate)), $locale));
+    }
+
+    /**
+     * @dataProvider preciseDifferenceDataProvider
+     */
+    public function test_humanize_time_period_precise(string $firstDate, string $secondDate, string $expected, string $locale) : void
     {
         $this->assertEquals($expected, DateTimeHumanizer::preciseDifference(new \DateTime($firstDate), new \DateTime($secondDate), $locale));
     }
 
     /**
-     * @return array
+     * @dataProvider timeUnitDataProvider
      */
-    public function humanizeDataProvider()
+    public function test_humanize_time_unit(Unit $unit, string $expected, string $locale) : void
+    {
+        $this->assertSame($expected, DateTimeHumanizer::timeUnit($unit, $locale));
+    }
+
+    public function humanizeDataProvider() : array
     {
         return [
             // English
@@ -264,10 +279,7 @@ public function humanizeDataProvider()
         ];
     }
 
-    /**
-     * @return array
-     */
-    public function preciseDifferenceDataProvider()
+    public function preciseDifferenceDataProvider() : array
     {
         return [
              // Azerbaijani
@@ -461,4 +473,39 @@ public function preciseDifferenceDataProvider()
             ['2014-04-26 13:00:00', '2016-04-27 13:00:00', '2 年, 1 日後', 'ja'],
         ];
     }
+
+    public function timeUnitDataProvider() : array
+    {
+        return [
+            // English
+            [TimeUnit::seconds(20), '20 seconds', 'en'],
+            [TimeUnit::minutes(20), '20 minutes', 'en'],
+            [TimeUnit::minutes(20)->add(TimeUnit::seconds(5)), '20 minutes and 5 seconds', 'en'],
+            [
+                TimeUnit::days(2)
+                    ->add(TimeUnit::hours(3))
+                    ->add(TimeUnit::minutes(25))
+                    ->add(TimeUnit::seconds(30))
+                    ->add(TimeUnit::milliseconds(200)),
+                '2 days, 3 hours, 25 minutes, and 30.2 seconds',
+                'en'
+            ],
+            [RelativeTimeUnit::months(14), '1 year and 2 months', 'en'],
+
+            // Polish
+            [TimeUnit::seconds(20), '20 sekund', 'pl'],
+            [TimeUnit::minutes(20), '20 minut', 'pl'],
+            [TimeUnit::minutes(20)->add(TimeUnit::seconds(5)), '20 minut i 5 sekund', 'pl'],
+            [
+                TimeUnit::days(2)
+                    ->add(TimeUnit::hours(3))
+                    ->add(TimeUnit::minutes(25))
+                    ->add(TimeUnit::seconds(30))
+                    ->add(TimeUnit::milliseconds(200)),
+                '2 dni, 3 godziny, 25 minut i 30.2 sekund',
+                'pl'
+            ],
+            [RelativeTimeUnit::months(14), '1 rok i 2 miesiące', 'pl']
+        ];
+    }
 }