Readme - TravisCI badge - do not support PHP 7.2, because friendsofphp/php-cs-fixer package can be run using PHP lower than 7.2 only

Details:
$ composer install
Your requirements could not be resolved to an installable set of packages
friendsofphp/php-cs-fixer v2.3.2 requires php ^5.6 || >=7.0 <7.2 -> your PHP version (7.3.0-dev) does not satisfy that requirement

.styleci.yml

@@ -0,0 +1 @@
+preset: symfony

.travis.yml

@@ -0,0 +1,12 @@
+language: php
+
+php:
+  - 5.6
+  - 7.0
+  - 7.1
+
+install:
+  - composer install
+
+script:
+  - php ./vendor/bin/phpunit

README.md

@@ -1,4 +1,4 @@
-# Meritoo Common Library
+# Meritoo Common Library [![Travis](https://img.shields.io/travis/rust-lang/rust.svg?style=flat-square)](https://travis-ci.org/meritoo/common-library) [![Packagist](https://img.shields.io/packagist/v/meritoo/common-library.svg?style=flat-square)](https://packagist.org/packages/meritoo/common-library) [![StyleCI](https://styleci.io/repos/101790028/shield?branch=master)](https://styleci.io/repos/101790028) [![license](https://img.shields.io/github/license/meritoo/common-library.svg?style=flat-square)](https://github.com/meritoo/common-library) [![GitHub commits](https://img.shields.io/github/commits-since/meritoo/common-library/0.0.1.svg?style=flat-square)](https://github.com/meritoo/common-library) [![Coverage Status](https://coveralls.io/repos/github/meritoo/common-library/badge.svg?branch=master)](https://coveralls.io/github/meritoo/common-library?branch=master)
 Useful classes, methods, extensions etc.
 
 ## Installation
@@ -11,15 +11,93 @@ Run [Composer](https://getcomposer.org) to install new package:
 
 > How to install Composer: https://getcomposer.org/download
 
-## Usage
+## Static methods
 
-This package contains a lot of static methods, so usage is not so complicated. Just run the static method who would you like to use. Example:
+This package contains a lot of class with static methods, so usage is not so complicated. Just run the static method who would you like to use. Example:
 
 ```php
 use Meritoo\Common\Utilities\Arrays;
 
-$firstElement = Arrays::getFirstElement(['lorem' 'ipsum']);
-// result: "lorem"
+$firstElement = Arrays::getFirstElement(['lorem', 'ipsum']);
+var_dump($firstElement); // string(5) "lorem"
+```
+
+## Base test case with common methods and data providers
+
+Located here: `Meritoo\Common\Test\Base\BaseTestCase`. Just extend the `BaseTestCase` class and use it like in `Meritoo\Common\Test\Utilities\DateTest` class:
+
+```php
+class DateTest extends BaseTestCase
+{
+    /**
+     * @param mixed $value Empty value, e.g. ""
+     * @dataProvider provideEmptyValue
+     */
+    public function testGetDateTimeEmptyValue($value)
+    {
+        self::assertFalse(Date::getDateTime($value));
+    }
+
+	(...)
+}
+```
+
+or in `Meritoo\Common\Test\Utilities\MimeTypesTest` class:
+
+```php
+class MimeTypesTest extends BaseTestCase
+{
+	(...)
+
+    /**
+     * @param bool $mimeType The mime type, e.g. "video/mpeg"
+     * @dataProvider provideBooleanValue
+     */
+    public function testGetExtensionBooleanMimeType($mimeType)
+    {
+        self::assertEquals('', MimeTypes::getExtension($mimeType));
+    }
+
+	(...)
+}
+```
+
+## Collection of elements
+
+Located here: `Meritoo\Common\Collection\Collection`. It's a set of some elements, e.g. objects. It's iterable and countable. Provides very useful methods. Some of them:
+- `getFirst()` - returns the first element in the collection
+- `getLast()` - returns the last element in the collection
+- `isEmpty()` - returns information if collection is empty
+- `add($element, $index = null)` - adds given element (at the end of collection)
+- `addMultiple($elements, $useIndexes = false)` - adds given elements (at the end of collection)
+- `prepend($element)` - prepends given element (adds given element at the beginning of collection)
+- `remove($element)` - removes given element
+
+Examples of usage below.
+
+#### An empty collection
+
+```php
+use Meritoo\Common\Collection\Collection;
+
+$emptyCollection = new Collection();
+var_dump($emptyCollection->isEmpty()); // bool(true)
+```
+
+#### Simple collection
+
+```php
+use Meritoo\Common\Collection\Collection;
+
+$elements = [
+    'lorem',
+    'ipsum',
+    123 => 'dolor',
+    345 => 'sit',
+];
+
+$simpleCollection = new Collection($elements);
+var_dump($simpleCollection->has('dolor')); // bool(true)
 ```
 
 Enjoy!

composer.json

@@ -2,7 +2,7 @@
     "name": "meritoo/common-library",
     "description": "Useful classes, methods, extensions etc.",
     "license": "MIT",
-    "version": "0.0.5",
+    "version": "0.0.7",
     "authors": [
         {
             "name": "Meritoo.pl",

tests/Meritoo/Common/Test/Utilities/DateTest.php

@@ -454,8 +454,11 @@ class DateTest extends BaseTestCase
         $start = 1;
         $end = 100;
 
-        $intervalMinDate = (clone $startDate)->add(new DateInterval(sprintf('P%dD', $start)));
-        $intervalMaxDate = (clone $startDate)->add(new DateInterval(sprintf('P%dD', $end)));
+        $minDate = clone $startDate;
+        $maxDate = clone $startDate;
+
+        $intervalMinDate = $minDate->add(new DateInterval(sprintf('P%dD', $start)));
+        $intervalMaxDate = $maxDate->add(new DateInterval(sprintf('P%dD', $end)));
 
         $randomDate = Date::getRandomDate();
         self::assertTrue($randomDate >= $intervalMinDate && $randomDate <= $intervalMaxDate);
@@ -471,7 +474,9 @@ class DateTest extends BaseTestCase
     public function testGetRandomDateIncorrectEnd(DateTime $startDate, $start, $end)
     {
         $randomDate = Date::getRandomDate($startDate, $start, $end);
-        $intervalDate = (clone $startDate)->add(new DateInterval(sprintf('P%dD', $start)));
+
+        $cloned = clone $startDate;
+        $intervalDate = $cloned->add(new DateInterval(sprintf('P%dD', $start)));
 
         self::assertTrue($randomDate >= $intervalDate && $randomDate <= $intervalDate);
     }
@@ -487,8 +492,11 @@ class DateTest extends BaseTestCase
     {
         $randomDate = Date::getRandomDate($startDate, $start, $end);
 
-        $intervalMinDate = (clone $startDate)->add(new DateInterval(sprintf('P%dD', $start)));
-        $intervalMaxDate = (clone $startDate)->add(new DateInterval(sprintf('P%dD', $end)));
+        $minDate = clone $startDate;
+        $maxDate = clone $startDate;
+
+        $intervalMinDate = $minDate->add(new DateInterval(sprintf('P%dD', $start)));
+        $intervalMaxDate = $maxDate->add(new DateInterval(sprintf('P%dD', $end)));
 
         self::assertTrue($randomDate >= $intervalMinDate && $randomDate <= $intervalMaxDate);
     }