diff --git a/.gitattributes b/.gitattributes
new file mode 100644
index 0000000..03efbe6
--- /dev/null
+++ b/.gitattributes
@@ -0,0 +1,8 @@
+tests export-ignore
+bin export-ignore
+.gitattributes export-ignore
+.gitignore export-ignore
+.travis.yml export-ignore
+phpcs.xml export-ignore
+README.md export-ignore
+LICENSE export-ignore
\ No newline at end of file
diff --git a/EventManager.php b/EventManager.php
new file mode 100644
index 0000000..16f190b
--- /dev/null
+++ b/EventManager.php
@@ -0,0 +1,136 @@
+<?php
+/**
+ * Event Manager for events and listeners.
+ * Based on https://carlalexander.ca/designing-system-wordpress-event-management/
+ *
+ * @package WPMedia\EventManager
+ */
+
+namespace WPMedia\EventManager;
+
+/**
+ * The event manager manages events using the WordPress plugin API.
+ */
+class EventManager
+{
+    /**
+     * WordPress plugin API manager
+     *
+     * @var PluginApiManager
+     */
+    private $plugin_api_manager;
+
+    /**
+     * Constructor
+     *
+     * @param PluginApiManager $plugin_api_manager WordPress plugin API manager.
+     */
+    public function __construct(PluginApiManager $plugin_api_manager)
+    {
+        $this->plugin_api_manager = $plugin_api_manager;
+    }
+
+    /**
+     * Adds the given event listener to the list of event listeners
+     *
+     * @param string   $event_name     Name of the event.
+     * @param callable $listener      Listener Callback function.
+     * @param int      $priority      Priority.
+     * @param int      $accepted_args Number of arguments.
+     */
+    public function addListener($event_name, $listener, $priority = 10, $accepted_args = 1)
+    {
+        $this->plugin_api_manager->addCallback($event_name, $listener, $priority, $accepted_args);
+    }
+
+    /**
+     * Adds an event subscriber.
+     *
+     * The event manager adds the given subscriber to the list of event listeners
+     * for all the events that it wants to listen to.
+     *
+     * @param SubscriberInterface $subscriber SubscriberInterface implementation.
+     */
+    public function addSubscriber(SubscriberInterface $subscriber)
+    {
+        if ($subscriber instanceof EventManagerAwareSubscriberInterface) {
+            $subscriber->setEventManager($this);
+        }
+
+        foreach ($subscriber->getSubscribedEvents() as $event_name => $parameters) {
+            $this->addSubscriberListener($subscriber, $event_name, $parameters);
+        }
+    }
+
+    /**
+     * Removes the given event listener from the list of event listeners
+     * that listen to the given event.
+     *
+     * @param string   $event_name Event name.
+     * @param callable $callback  Callback.
+     * @param int      $priority  Priority.
+     *
+     * @return bool
+     */
+    public function removeListener($event_name, $callback, $priority = 10)
+    {
+        return $this->plugin_api_manager->removeCallback($event_name, $callback, $priority);
+    }
+
+    /**
+     * Removes an event subscriber.
+     *
+     * The event manager removes the given subscriber from the list of event listeners
+     * for all the events that it wants to listen to.
+     *
+     * @param SubscriberInterface $subscriber SubscriberInterface implementation.
+     */
+    public function removeSubscriber(SubscriberInterface $subscriber)
+    {
+        foreach ($subscriber->getSubscribedEvents() as $event_name => $parameters) {
+            $this->removeSubscriberListener($subscriber, $event_name, $parameters);
+        }
+    }
+
+    /**
+     * Adds the given subscriber listener to the list of event listeners
+     * that listen to the given event.
+     *
+     * @param SubscriberInterface $subscriber SubscriberInterface implementation.
+     * @param string              $event_name Event name.
+     * @param mixed               $parameters Parameters, can be a string, an array or a multidimensional array.
+     */
+    private function addSubscriberListener(SubscriberInterface $subscriber, $event_name, $parameters)
+    {
+        if (is_string($parameters)) {
+            $this->addListener($event_name, [ $subscriber, $parameters ]);
+        } elseif (is_array($parameters) && count($parameters) !== count($parameters, COUNT_RECURSIVE)) {
+            foreach ($parameters as $parameter) {
+                $this->addSubscriberListener($subscriber, $event_name, $parameter);
+            }
+        } elseif (is_array($parameters) && isset($parameters[0])) {
+            $this->addListener($event_name, [ $subscriber, $parameters[0] ], isset($parameters[1]) ? $parameters[1] : 10, isset($parameters[2]) ? $parameters[2] : 1);
+        }
+    }
+
+    /**
+     * Removes the given subscriber listener to the list of event listeners
+     * that listen to the given event.
+     *
+     * @param SubscriberInterface $subscriber SubscriberInterface implementation.
+     * @param string              $event_name Event name.
+     * @param mixed               $parameters Parameters, can be a string, an array or a multidimensional array.
+     */
+    private function removeSubscriberListener(SubscriberInterface $subscriber, $event_name, $parameters)
+    {
+        if (is_string($parameters)) {
+            $this->removeListener($event_name, [ $subscriber, $parameters ]);
+        } elseif (is_array($parameters) && count($parameters) !== count($parameters, COUNT_RECURSIVE)) {
+            foreach ($parameters as $parameter) {
+                $this->removeSubscriberListener($subscriber, $event_name, $parameter);
+            }
+        } elseif (is_array($parameters) && isset($parameters[0])) {
+            $this->removeListener($event_name, [ $subscriber, $parameters[0] ], isset($parameters[1]) ? $parameters[1] : 10);
+        }
+    }
+}
diff --git a/EventManagerAwareSubscriberInterface.php b/EventManagerAwareSubscriberInterface.php
new file mode 100644
index 0000000..4b02709
--- /dev/null
+++ b/EventManagerAwareSubscriberInterface.php
@@ -0,0 +1,18 @@
+<?php
+/**
+ * Interface for subscribers who need access to the event manager object
+ *
+ * @package WPMedia\EventManager
+ */
+
+namespace WPMedia\EventManager;
+
+interface EventManagerAwareSubscriberInterface extends SubscriberInterface
+{
+    /**
+     * Set the WordPress event manager for the subscriber.
+     *
+     * @param EventManager $event_manager EventManager instance.
+     */
+    public function setEventManager(EventManager $event_manager);
+}
diff --git a/PluginApiManager.php b/PluginApiManager.php
new file mode 100644
index 0000000..788f1c4
--- /dev/null
+++ b/PluginApiManager.php
@@ -0,0 +1,102 @@
+<?php
+/**
+ * Based on https://carlalexander.ca/designing-system-wordpress-event-management/
+ *
+ * @package WPMedia\EventManager
+ */
+
+namespace WPMedia\EventManager;
+
+/**
+ * Wrapper class around the WordPress plugin API
+ */
+class PluginApiManager
+{
+    /**
+     * Adds a callback to a specific hook of the WordPress plugin API.
+     *
+     * @uses add_filter()
+     *
+     * @param string   $hook_name     Name of the hook.
+     * @param callable $callback      Callback function.
+     * @param int      $priority      Priority.
+     * @param int      $accepted_args Number of arguments.
+     */
+    public function addCallback($hook_name, $callback, $priority = 10, $accepted_args = 1)
+    {
+        add_filter($hook_name, $callback, $priority, $accepted_args);
+    }
+
+    /**
+     * Removes the given callback from the given hook. The WordPress plugin API only
+     * removes the hook if the callback and priority match a registered hook.
+     *
+     * @uses remove_filter()
+     *
+     * @param string   $hook_name Hook name.
+     * @param callable $callback  Callback.
+     * @param int      $priority  Priority.
+     *
+     * @return bool
+     */
+    public function removeCallback($hook_name, $callback, $priority = 10)
+    {
+        return remove_filter($hook_name, $callback, $priority);
+    }
+
+    /**
+     * Checks the WordPress plugin API to see if the given hook has
+     * the given callback. The priority of the callback will be returned
+     * or false. If no callback is given will return true or false if
+     * there's any callbacks registered to the hook.
+     *
+     * @uses has_filter()
+     *
+     * @param string $hook_name Hook name.
+     * @param mixed  $callback  Callback.
+     *
+     * @return bool|int
+     */
+    public function hasCallback($hook_name, $callback = false)
+    {
+        return has_filter($hook_name, $callback);
+    }
+
+    /**
+     * Get the name of the hook that WordPress plugin API is executing. Returns
+     * false if it isn't executing a hook.
+     *
+     * @uses current_filter()
+     *
+     * @return string|bool
+     */
+    public function getCurrentHook()
+    {
+        return current_filter();
+    }
+
+    /**
+     * Executes all the callbacks registered with the given hook.
+     *
+     * @uses do_action()
+     */
+    public function execute()
+    {
+        $args = func_get_args();
+        return call_user_func_array('do_action', $args);
+    }
+ 
+    /**
+     * Filters the given value by applying all the changes from the callbacks
+     * registered with the given hook. Returns the filtered value.
+     *
+     * @uses apply_filters()
+     *
+     * @return mixed
+     */
+    public function filter()
+    {
+        $args = func_get_args();
+        return call_user_func_array('apply_filters', $args);
+    }
+}
diff --git a/SubscriberInterface.php b/SubscriberInterface.php
new file mode 100644
index 0000000..6a7b4ee
--- /dev/null
+++ b/SubscriberInterface.php
@@ -0,0 +1,38 @@
+<?php
+/**
+ * Interface for subscribers
+ *
+ * @package WPMedia\EventManager
+ */
+
+namespace WPMedia\EventManager;
+
+/**
+ * A Subscriber knows what specific WordPress events it wants to listen to.
+ *
+ * When an EventManager adds a Subscriber, it gets all the WordPress events that
+ * it wants to listen to. It then adds the subscriber as a listener for each of them.
+ */
+interface SubscriberInterface
+{
+    /**
+     * Returns an array of events that this subscriber wants to listen to.
+     *
+     * The array key is the event name. The value can be:
+     *
+     *  * The method name
+     *  * An array with the method name and priority
+     *  * An array with the method name, priority and number of accepted arguments
+     *  * An array containing arrays following the above patterns
+     *
+     * For instance:
+     *
+     *  * array('event_name' => 'method_name')
+     *  * array('event_name' => array('method_name', $priority))
+     *  * array('event_name' => array('method_name', $priority, $accepted_args))
+     *  * array('event_name' => array(array('method_name_1', $priority_1, $accepted_args_1)), array('method_name_2', $priority_2, $accepted_args_2)))
+     *
+     * @return array
+     */
+    public static function getSubscribedEvents();
+}
diff --git a/bin/install-wp-tests.sh b/bin/install-wp-tests.sh
new file mode 100644
index 0000000..878881f
--- /dev/null
+++ b/bin/install-wp-tests.sh
@@ -0,0 +1,152 @@
+#!/usr/bin/env bash
+
+if [ $# -lt 3 ]; then
+	echo "usage: $0 <db-name> <db-user> <db-pass> [db-host] [wp-version] [skip-database-creation]"
+	exit 1
+fi
+
+DB_NAME=$1
+DB_USER=$2
+DB_PASS=$3
+DB_HOST=${4-localhost}
+WP_VERSION=${5-latest}
+SKIP_DB_CREATE=${6-false}
+
+TMPDIR=${TMPDIR-/tmp}
+TMPDIR=$(echo $TMPDIR | sed -e "s/\/$//")
+WP_TESTS_DIR=${WP_TESTS_DIR-$TMPDIR/wordpress-tests-lib}
+WP_CORE_DIR=${WP_CORE_DIR-$TMPDIR/wordpress/}
+
+download() {
+    if [ `which curl` ]; then
+        curl -s "$1" > "$2";
+    elif [ `which wget` ]; then
+        wget -nv -O "$2" "$1"
+    fi
+}
+
+if [[ $WP_VERSION =~ ^[0-9]+\.[0-9]+$ ]]; then
+	WP_TESTS_TAG="branches/$WP_VERSION"
+elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0-9]+ ]]; then
+	if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+		# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+		WP_TESTS_TAG="tags/${WP_VERSION%??}"
+	else
+		WP_TESTS_TAG="tags/$WP_VERSION"
+	fi
+elif [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
+	WP_TESTS_TAG="trunk"
+else
+	# http serves a single offer, whereas https serves multiple. we only want one
+	download http://api.wordpress.org/core/version-check/1.7/ /tmp/wp-latest.json
+	grep '[0-9]+\.[0-9]+(\.[0-9]+)?' /tmp/wp-latest.json
+	LATEST_VERSION=$(grep -o '"version":"[^"]*' /tmp/wp-latest.json | sed 's/"version":"//')
+	if [[ -z "$LATEST_VERSION" ]]; then
+		echo "Latest WordPress version could not be found"
+		exit 1
+	fi
+	WP_TESTS_TAG="tags/$LATEST_VERSION"
+fi
+
+set -ex
+
+install_wp() {
+
+	if [ -d $WP_CORE_DIR ]; then
+		return;
+	fi
+
+	mkdir -p $WP_CORE_DIR
+
+	if [[ $WP_VERSION == 'nightly' || $WP_VERSION == 'trunk' ]]; then
+		mkdir -p $TMPDIR/wordpress-nightly
+		download https://wordpress.org/nightly-builds/wordpress-latest.zip  $TMPDIR/wordpress-nightly/wordpress-nightly.zip
+		unzip -q $TMPDIR/wordpress-nightly/wordpress-nightly.zip -d $TMPDIR/wordpress-nightly/
+		mv $TMPDIR/wordpress-nightly/wordpress/* $WP_CORE_DIR
+	else
+		if [ $WP_VERSION == 'latest' ]; then
+			local ARCHIVE_NAME='latest'
+		elif [[ $WP_VERSION =~ [0-9]+\.[0-9]+ ]]; then
+			# https serves multiple offers, whereas http serves single.
+			download https://api.wordpress.org/core/version-check/1.7/ $TMPDIR/wp-latest.json
+			if [[ $WP_VERSION =~ [0-9]+\.[0-9]+\.[0] ]]; then
+				# version x.x.0 means the first release of the major version, so strip off the .0 and download version x.x
+				LATEST_VERSION=${WP_VERSION%??}
+			else
+				# otherwise, scan the releases and get the most up to date minor version of the major release
+				local VERSION_ESCAPED=`echo $WP_VERSION | sed 's/\./\\\\./g'`
+				LATEST_VERSION=$(grep -o '"version":"'$VERSION_ESCAPED'[^"]*' $TMPDIR/wp-latest.json | sed 's/"version":"//' | head -1)
+			fi
+			if [[ -z "$LATEST_VERSION" ]]; then
+				local ARCHIVE_NAME="wordpress-$WP_VERSION"
+			else
+				local ARCHIVE_NAME="wordpress-$LATEST_VERSION"
+			fi
+		else
+			local ARCHIVE_NAME="wordpress-$WP_VERSION"
+		fi
+		download https://wordpress.org/${ARCHIVE_NAME}.tar.gz  $TMPDIR/wordpress.tar.gz
+		tar --strip-components=1 -zxmf $TMPDIR/wordpress.tar.gz -C $WP_CORE_DIR
+	fi
+
+	download https://raw.github.com/markoheijnen/wp-mysqli/master/db.php $WP_CORE_DIR/wp-content/db.php
+}
+
+install_test_suite() {
+	# portable in-place argument for both GNU sed and Mac OSX sed
+	if [[ $(uname -s) == 'Darwin' ]]; then
+		local ioption='-i .bak'
+	else
+		local ioption='-i'
+	fi
+
+	# set up testing suite if it doesn't yet exist
+	if [ ! -d $WP_TESTS_DIR ]; then
+		# set up testing suite
+		mkdir -p $WP_TESTS_DIR
+		svn co --quiet https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/includes/ $WP_TESTS_DIR/includes
+		svn co --quiet https://develop.svn.wordpress.org/${WP_TESTS_TAG}/tests/phpunit/data/ $WP_TESTS_DIR/data
+	fi
+
+	if [ ! -f wp-tests-config.php ]; then
+		download https://develop.svn.wordpress.org/${WP_TESTS_TAG}/wp-tests-config-sample.php "$WP_TESTS_DIR"/wp-tests-config.php
+		# remove all forward slashes in the end
+		WP_CORE_DIR=$(echo $WP_CORE_DIR | sed "s:/\+$::")
+		sed $ioption "s:dirname( __FILE__ ) . '/src/':'$WP_CORE_DIR/':" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/youremptytestdbnamehere/$DB_NAME/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/yourusernamehere/$DB_USER/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s/yourpasswordhere/$DB_PASS/" "$WP_TESTS_DIR"/wp-tests-config.php
+		sed $ioption "s|localhost|${DB_HOST}|" "$WP_TESTS_DIR"/wp-tests-config.php
+	fi
+
+}
+
+install_db() {
+
+	if [ ${SKIP_DB_CREATE} = "true" ]; then
+		return 0
+	fi
+
+	# parse DB_HOST for port or socket references
+	local PARTS=(${DB_HOST//\:/ })
+	local DB_HOSTNAME=${PARTS[0]};
+	local DB_SOCK_OR_PORT=${PARTS[1]};
+	local EXTRA=""
+
+	if ! [ -z $DB_HOSTNAME ] ; then
+		if [ $(echo $DB_SOCK_OR_PORT | grep -e '^[0-9]\{1,\}$') ]; then
+			EXTRA=" --host=$DB_HOSTNAME --port=$DB_SOCK_OR_PORT --protocol=tcp"
+		elif ! [ -z $DB_SOCK_OR_PORT ] ; then
+			EXTRA=" --socket=$DB_SOCK_OR_PORT"
+		elif ! [ -z $DB_HOSTNAME ] ; then
+			EXTRA=" --host=$DB_HOSTNAME --protocol=tcp"
+		fi
+	fi
+
+	# create database
+	mysqladmin create $DB_NAME --user="$DB_USER" --password="$DB_PASS"$EXTRA
+}
+
+install_wp
+install_test_suite
+install_db
diff --git a/composer.json b/composer.json
index 8c7ed7c..a83fe78 100644
--- a/composer.json
+++ b/composer.json
@@ -31,13 +31,14 @@
     },
     "autoload": {
         "psr-4": {
-            "WP_Media\\EventManager\\": "src/"
+            "WPMedia\\EventManager\\": ""
         }
     },
     "autoload-dev": {
         "psr-4": {
-            "WP_Media\\EventManager\\Tests\\Unit\\": "test/Unit",
-            "WP_Media\\EventManager\\Tests\\Integration\\": "test/Integration"
+            "WPMedia\\EventManager\\Tests\\Unit\\": "tests/Unit",
+            "WPMedia\\EventManager\\Tests\\Integration\\": "tests/Integration",
+            "WPMedia\\EventManager\\Tests\\Fixtures\\": "tests/Fixtures"
         }
     },
     "scripts": {
diff --git a/tests/Fixtures/DummySubscriber.php b/tests/Fixtures/DummySubscriber.php
new file mode 100644
index 0000000..31f5a44
--- /dev/null
+++ b/tests/Fixtures/DummySubscriber.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Fixtures;
+
+use WPMedia\EventManager\SubscriberInterface;
+
+/**
+ * Dummy subscriber for tests
+ */
+class DummySubscriber implements SubscriberInterface {
+    public static function getSubscribedEvents() {
+        return [
+            'foo' => 'bar',
+            'foofoo' => [ 'barbar', 20 ],
+            'foobar' => [ 'foobarbar', 50, 3 ],
+            'barfoo' => [
+                [ 'filter_this' ],
+                [ 'filter_that', 10, 2 ],
+            ],
+        ];
+    }
+}
diff --git a/tests/Integration/EventManager/addSubscriber.php b/tests/Integration/EventManager/addSubscriber.php
new file mode 100644
index 0000000..63c5383
--- /dev/null
+++ b/tests/Integration/EventManager/addSubscriber.php
@@ -0,0 +1,47 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\EventManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use WPMedia\EventManager\EventManager;
+use WPMedia\EventManager\PluginApiManager;
+use WPMedia\EventManager\Tests\Fixtures\DummySubscriber;
+
+/**
+ * Tests for the addSubscriber method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::addSubscriber
+ * @group EventManager
+ */
+class Test_AddSubscriber extends TestCase {
+    /**
+     * Test should register listeners for each event listed in the subscriber
+     */
+    public function testShouldAddListenersToEventsFromSubscriber() {
+        $manager    = new EventManager(new PluginApiManager());
+        $subscriber = new DummySubscriber();
+
+        $manager->addSubscriber($subscriber);
+
+        $this->assertSame(
+            10,
+            has_filter('foo', [ $subscriber, 'bar' ])
+        );
+        $this->assertSame(
+            20,
+            has_filter('foofoo', [ $subscriber, 'barbar' ])
+        );
+        $this->assertSame(
+            50,
+            has_filter('foobar', [ $subscriber, 'foobarbar' ])
+        );
+        $this->assertSame(
+            10,
+            has_filter('barfoo', [ $subscriber, 'filter_this' ])
+        );
+        $this->assertSame(
+            10,
+            has_filter('barfoo', [ $subscriber, 'filter_that' ])
+        );
+    }
+}
diff --git a/tests/Integration/EventManager/removeSubscriber.php b/tests/Integration/EventManager/removeSubscriber.php
new file mode 100644
index 0000000..7aca294
--- /dev/null
+++ b/tests/Integration/EventManager/removeSubscriber.php
@@ -0,0 +1,33 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\EventManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use WPMedia\EventManager\EventManager;
+use WPMedia\EventManager\PluginApiManager;
+use WPMedia\EventManager\Tests\Fixtures\DummySubscriber;
+
+/**
+ * Tests for the removeSubscriber method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::removeSubscriber
+ * @group EventManager
+ */
+class Test_RemoveSubscriber extends TestCase {
+    /**
+     * Test should remove listeners from events listed in the subscriber
+     */
+    public function testShouldRemoveListenersFromEventsFromSubscriber() {
+        $manager    = new EventManager(new PluginApiManager());
+        $subscriber = new DummySubscriber();
+
+        $manager->addSubscriber($subscriber);
+        $manager->removeSubscriber($subscriber);
+
+        $this->assertFalse(has_filter('foo', [ $subscriber, 'bar' ]));
+        $this->assertFalse(has_filter('foofoo', [ $subscriber, 'barbar' ]));
+        $this->assertFalse(has_filter('foobar', [ $subscriber, 'foobarbar' ]));
+        $this->assertFalse(has_filter('barfoo', [ $subscriber, 'filter_this' ]));
+        $this->assertFalse(has_filter('barfoo', [ $subscriber, 'filter_that' ]));
+    }
+}
diff --git a/tests/Integration/PluginApiManager/addCallback.php b/tests/Integration/PluginApiManager/addCallback.php
new file mode 100644
index 0000000..7fbec41
--- /dev/null
+++ b/tests/Integration/PluginApiManager/addCallback.php
@@ -0,0 +1,39 @@
+<?php
+namespace WPMedia\EventManager\Tests\Integration\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the addCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::addCallback
+ * @group PluginApiManager
+ */
+class Test_AddCallback extends TestCase {
+    /**
+     * Test should add a new filter with default priority and arguments
+     */
+    public function testShouldAddNewFilterWithDefaultParameters() {
+        $plugin_api_manager = new PluginApiManager();
+        $plugin_api_manager->addCallback('the_content', 'strtolower');
+
+        $this->assertSame(
+            10,
+            has_filter('the_content', 'strtolower')
+        );
+    }
+
+    /**
+     * Test should add a new filter with a priority 100 and 3 arguments
+     */
+    public function testShouldAddNewFilterWithAllParameters() {
+        $plugin_api_manager = new PluginApiManager();
+        $plugin_api_manager->addCallback('the_content', 'strtolower', 100, 3);
+
+        $this->assertSame(
+            100,
+            has_filter('the_content', 'strtolower')
+        );
+    }
+}
diff --git a/tests/Integration/PluginApiManager/execute.php b/tests/Integration/PluginApiManager/execute.php
new file mode 100644
index 0000000..575d7ae
--- /dev/null
+++ b/tests/Integration/PluginApiManager/execute.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use Brain\Monkey\Actions;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the execute method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::execute
+ * @group PluginApiManager
+ */
+class Test_Execute extends TestCase {
+    /**
+     * Test should assert the given action was fired once
+     */
+    public function testShouldAssertExecutedHook() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $plugin_api_manager->execute('my_action');
+
+        $this->assertSame(1, did_action('my_action'));
+    }
+}
\ No newline at end of file
diff --git a/tests/Integration/PluginApiManager/filter.php b/tests/Integration/PluginApiManager/filter.php
new file mode 100644
index 0000000..09626cc
--- /dev/null
+++ b/tests/Integration/PluginApiManager/filter.php
@@ -0,0 +1,31 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use Brain\Monkey\Filters;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the filter method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::filter
+ * @group PluginApiManager
+ */
+class Test_Filter extends TestCase {
+    /**
+     * Test should assert the given filter was fired at least once
+     */
+    public function testShouldAssertExecutedHook() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $plugin_api_manager->filter('my_filter', 'filter value');
+
+        add_filter('my_filter', 'strtoupper');
+
+        $this->assertSame(
+            10,
+            has_filter('my_filter', 'strtoupper')
+        );
+    }
+}
diff --git a/tests/Integration/PluginApiManager/hasCallback.php b/tests/Integration/PluginApiManager/hasCallback.php
new file mode 100644
index 0000000..ecf81ff
--- /dev/null
+++ b/tests/Integration/PluginApiManager/hasCallback.php
@@ -0,0 +1,59 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the hasCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::hasCallback
+ * @group PluginApiManager
+ */
+class Test_HasCallback extends TestCase {
+    /**
+     * Test should return false when no callback is attached to the given hook.
+     */
+    public function testShouldReturnFalseWhenNoCallbackAttached() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->hasCallback('my_custom_filter'));
+    }
+
+    /**
+     * Test should return true when a callback is attached to the given hook.
+     */
+    public function testShouldReturnTrueWhenCallbackAttached() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->hasCallback('the_content'));
+    }
+
+    /**
+     * Test should return false when the given callback is not attached to the given hook.
+     */
+    public function testShouldReturnFalseWhenCallbackNotAttached() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->hasCallback('the_content', 'strtoupper'));
+    }
+
+    /**
+     * Test should return true when the given callback is attached to the given hook.
+     */
+    public function testShouldReturnPriorityIntWhenCallbackAttached() {
+        add_filter('the_content', 'strtolower', 11);
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertSame(
+            11,
+            $plugin_api_manager->hasCallback('the_content', 'strtolower')
+        );
+    }
+}
diff --git a/tests/Integration/PluginApiManager/removeCallback.php b/tests/Integration/PluginApiManager/removeCallback.php
new file mode 100644
index 0000000..732f632
--- /dev/null
+++ b/tests/Integration/PluginApiManager/removeCallback.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Integration\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Integration\TestCase;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the removeCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::removeCallback
+ * @group PluginApiManager
+ */
+class Test_RemoveCallback extends TestCase {
+    /**
+     * Test should return true when the given callback is removed from the given hook
+     */
+    public function testShouldReturnTrueWhenCallbackRemoved() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->removeCallback('the_content', 'strtolower'));
+    }
+
+    /**
+     * Test should return false when the given callback doesn't exist for the given hook
+     */
+    public function testShouldReturnFalseWhenCallbackDoesNotExist() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->removeCallback('the_content', 'strtoupper'));
+    }
+
+    /**
+     * Test should return false when the given callback priority doesn't match with the priority when added
+     */
+    public function testShouldReturnFalseWhenPriorityDoesNotMatch() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->removeCallback('the_content', 'strtolower', 100));
+    }
+
+    /**
+     * Test should return true when the given callback priority matches with the priority when added
+     */
+    public function testShouldReturnTrueWhenPriorityMatches() {
+        add_filter('the_content', 'strtolower', 100);
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->removeCallback('the_content', 'strtolower', 100));
+    }
+}
diff --git a/tests/Integration/TestCase.php b/tests/Integration/TestCase.php
new file mode 100644
index 0000000..ecc9ad4
--- /dev/null
+++ b/tests/Integration/TestCase.php
@@ -0,0 +1,31 @@
+<?php
+/**
+ * Test Case for all of the integration tests.
+ *
+ * @package WPMedia\EventManager\Tests\Integration
+ */
+
+namespace WPMedia\EventManager\Tests\Integration;
+
+use Brain\Monkey;
+use WPMedia\EventManager\Tests\TestCaseTrait;
+use WP_UnitTestCase;
+
+abstract class TestCase extends WP_UnitTestCase {
+    use TestCaseTrait;
+    /**
+     * Prepares the test environment before each test.
+     */
+    public function setUp() {
+        parent::setUp();
+        Monkey\setUp();
+    }
+
+    /**
+     * Cleans up the test environment after each test.
+     */
+    public function tearDown() {
+        Monkey\tearDown();
+        parent::tearDown();
+    }
+}
diff --git a/tests/Integration/bootstrap.php b/tests/Integration/bootstrap.php
new file mode 100644
index 0000000..017ff18
--- /dev/null
+++ b/tests/Integration/bootstrap.php
@@ -0,0 +1,53 @@
+<?php
+/**
+ * Bootstraps the plugin's integration tests
+ *
+ * @package WPMedia\EventManager\Tests\Integration
+ */
+
+namespace WPMedia\EventManager\Tests\Integration;
+
+use Brain\Monkey;
+use WPMedia\EventManager\Tests\Fixtures\Redis;
+use function WPMedia\EventManager\Tests\init_test_suite;
+
+require_once dirname( dirname( __FILE__ ) ) . '/bootstrap-functions.php';
+init_test_suite( 'Integration' );
+
+/**
+ * Get the WordPress' tests suite directory.
+ *
+ * @return string Returns The directory path to the WordPress testing environment.
+ */
+function get_wp_tests_dir() {
+    $tests_dir = getenv( 'WP_TESTS_DIR' );
+    // Travis CI & Vagrant SSH tests directory.
+    if ( empty( $tests_dir ) ) {
+        $tests_dir = '/tmp/wordpress-tests-lib';
+    }
+    // If the tests' includes directory does not exist, try a relative path to Core tests directory.
+    if ( ! file_exists( $tests_dir . '/includes/' ) ) {
+        $tests_dir = '../../../../tests/phpunit';
+    }
+    // Check it again. If it doesn't exist, stop here and post a message as to why we stopped.
+    if ( ! file_exists( $tests_dir . '/includes/' ) ) {
+        trigger_error( 'Unable to run the integration tests, because the WordPress test suite could not be located.', E_USER_ERROR ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error -- Valid use case for our testing suite.
+    }
+    // Strip off the trailing directory separator, if it exists.
+    return rtrim( $tests_dir, DIRECTORY_SEPARATOR );
+}
+
+/**
+ * Bootstraps the integration testing environment with WordPress and this plugin.
+ *
+ * @param string $wp_tests_dir The directory path to the WordPress testing environment.
+ */
+function bootstrap_integration_suite( $wp_tests_dir ) {
+    // Give access to tests_add_filter() function.
+    require_once $wp_tests_dir . '/includes/functions.php';
+
+    // Start up the WP testing environment.
+    require_once $wp_tests_dir . '/includes/bootstrap.php';
+}
+
+bootstrap_integration_suite( get_wp_tests_dir() );
diff --git a/tests/Integration/phpunit.xml.dist b/tests/Integration/phpunit.xml.dist
new file mode 100644
index 0000000..0c19f29
--- /dev/null
+++ b/tests/Integration/phpunit.xml.dist
@@ -0,0 +1,22 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+		 xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.3/phpunit.xsd"
+		 bootstrap="bootstrap.php"
+		 backupGlobals="false"
+		 colors="true"
+		 beStrictAboutCoversAnnotation="true"
+		 beStrictAboutOutputDuringTests="true"
+		 beStrictAboutTestsThatDoNotTestAnything="true"
+		 beStrictAboutTodoAnnotatedTests="true"
+		 convertErrorsToExceptions="true"
+		 convertNoticesToExceptions="true"
+		 convertWarningsToExceptions="true"
+		 verbose="true">
+
+	<testsuites>
+		<testsuite name="integration">
+			<directory suffix=".php">.</directory>
+			<exclude>TestCase.php</exclude>
+		</testsuite>
+	</testsuites>
+</phpunit>
\ No newline at end of file
diff --git a/tests/TestCaseTrait.php b/tests/TestCaseTrait.php
new file mode 100644
index 0000000..f3f3c15
--- /dev/null
+++ b/tests/TestCaseTrait.php
@@ -0,0 +1,59 @@
+<?php
+/**
+ * Common functionality for all PHP test cases.
+ *
+ * @package WPMedia\EventManager\Tests
+ */
+
+namespace WPMedia\EventManager\Tests;
+
+trait TestCaseTrait {
+    /**
+     * Get reflective access to the private/protected method.
+     *
+     * @param string $method_name Method name for which to gain access.
+     * @param string $class_name  Name of the target class.
+     *
+     * @return \ReflectionMethod
+     * @throws \ReflectionException Throws an exception if method does not exist.
+     */
+    protected function get_reflective_method( $method_name, $class_name ) {
+        $class  = new \ReflectionClass( $class_name );
+        $method = $class->getMethod( $method_name );
+        $method->setAccessible( true );
+        return $method;
+    }
+
+    /**
+     * Get reflective access to the private/protected property.
+     *
+     * @param string       $property Property name for which to gain access.
+     * @param string|mixed $class    Class name or instance.
+     *
+     * @return \ReflectionProperty|string
+     * @throws \ReflectionException Throws an exception if property does not exist.
+     */
+    protected function get_reflective_property( $property, $class ) {
+        $class    = new \ReflectionClass( $class );
+        $property = $class->getProperty( $property );
+        $property->setAccessible( true );
+        return $property;
+    }
+
+    /**
+     * Set the value of a property or private property.
+     *
+     * @param mixed  $value    The value to set for the property.
+     * @param string $property Property name for which to gain access.
+     * @param mixed  $instance Instance of the target object.
+     *
+     * @return \ReflectionProperty|string
+     * @throws \ReflectionException Throws an exception if property does not exist.
+     */
+    protected function set_reflective_property( $value, $property, $instance ) {
+        $property = $this->get_reflective_property( $property, $instance );
+        $property->setValue( $instance, $value );
+        $property->setAccessible( false );
+        return $property;
+    }
+}
diff --git a/tests/Unit/EventManager/addSubscriber.php b/tests/Unit/EventManager/addSubscriber.php
new file mode 100644
index 0000000..a0a3785
--- /dev/null
+++ b/tests/Unit/EventManager/addSubscriber.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\EventManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use WPMedia\EventManager\EventManager;
+use WPMedia\EventManager\PluginApiManager;
+use WPMedia\EventManager\Tests\Fixtures\DummySubscriber;
+
+/**
+ * Tests for the addSubscriber
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::addSubscriber
+ * @group EventManager
+ */
+class Test_AddSubscriber extends TestCase {
+    /**
+     * Test should register listeners to events 5 times
+     */
+    public function testShouldAddListenersToEventsFromSubscriber() {
+        $plugin_api_manager = \Mockery::mock(PluginApiManager::class);
+        $plugin_api_manager->shouldReceive('addCallback')
+        ->times(5);
+
+        $manager = new EventManager($plugin_api_manager);
+
+        $manager->addSubscriber(new DummySubscriber());
+    }
+}
diff --git a/tests/Unit/EventManager/removeSubscriber.php b/tests/Unit/EventManager/removeSubscriber.php
new file mode 100644
index 0000000..767597b
--- /dev/null
+++ b/tests/Unit/EventManager/removeSubscriber.php
@@ -0,0 +1,29 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\EventManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use WPMedia\EventManager\EventManager;
+use WPMedia\EventManager\PluginApiManager;
+use WPMedia\EventManager\Tests\Fixtures\DummySubscriber;
+
+/**
+ * Tests for the removeSubscriber method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::removeSubscriber
+ * @group EventManager
+ */
+class Test_RemoveSubscriber extends TestCase {
+    /**
+     * Test should remove listeners from events 5 times
+     */
+    public function testShouldRemoveListenersFromEventsFromSubscriber() {
+        $plugin_api_manager = \Mockery::mock(PluginApiManager::class);
+        $plugin_api_manager->shouldReceive('removeCallback')
+        ->times(5);
+
+        $manager = new EventManager($plugin_api_manager);
+
+        $manager->removeSubscriber(new DummySubscriber());
+    }
+}
diff --git a/tests/Unit/PluginApiManager/addCallback.php b/tests/Unit/PluginApiManager/addCallback.php
new file mode 100644
index 0000000..030c712
--- /dev/null
+++ b/tests/Unit/PluginApiManager/addCallback.php
@@ -0,0 +1,37 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use Brain\Monkey\Filters;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the addCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::addCallback
+ * @group PluginApiManager
+ */
+class Test_AddCallback extends TestCase {
+    /**
+     * Test should add a new filter with default priority and arguments
+     */
+    public function testShouldAddNewFilterWithDefaultParameters() {
+        Filters\expectAdded('the_content')
+        ->with('strtolower', 10, 1);
+
+        $plugin_api_manager = new PluginApiManager();
+        $plugin_api_manager->addCallback('the_content', 'strtolower');
+    }
+
+    /**
+     * Test should add a new filter with a priority 100 and 3 arguments
+     */
+    public function testShouldAddNewFilterWithAllParameters() {
+        Filters\expectAdded('the_content')
+        ->with('strtolower', 100, 3);
+
+        $plugin_api_manager = new PluginApiManager();
+        $plugin_api_manager->addCallback('the_content', 'strtolower', 100, 3);
+    }
+}
diff --git a/tests/Unit/PluginApiManager/execute.php b/tests/Unit/PluginApiManager/execute.php
new file mode 100644
index 0000000..4cc3c80
--- /dev/null
+++ b/tests/Unit/PluginApiManager/execute.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use Brain\Monkey\Actions;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the execute method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::execute
+ * @group PluginApiManager
+ */
+class Test_Execute extends TestCase {
+    /**
+     * Test should assert the given action was fired once
+     */
+    public function testShouldAssertExecutedHook() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $plugin_api_manager->execute('my_action');
+
+        $this->assertSame(1, did_action('my_action'));
+    }
+}
diff --git a/tests/Unit/PluginApiManager/filter.php b/tests/Unit/PluginApiManager/filter.php
new file mode 100644
index 0000000..24d6177
--- /dev/null
+++ b/tests/Unit/PluginApiManager/filter.php
@@ -0,0 +1,26 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use Brain\Monkey\Filters;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the filter method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::filter
+ * @group PluginApiManager
+ */
+class Test_Filter extends TestCase {
+    /**
+     * Test should assert the given filter was fired at least once
+     */
+    public function testShouldAssertExecutedHook() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $plugin_api_manager->filter('my_filter', 'filter value');
+
+        $this->assertTrue(Filters\applied('my_filter') > 0);
+    }
+}
diff --git a/tests/Unit/PluginApiManager/hasCallback.php b/tests/Unit/PluginApiManager/hasCallback.php
new file mode 100644
index 0000000..ccbf1db
--- /dev/null
+++ b/tests/Unit/PluginApiManager/hasCallback.php
@@ -0,0 +1,56 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the hasCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::hasCallback
+ * @group PluginApiManager
+ */
+class Test_HasCallback extends TestCase {
+    /**
+     * Test should return false when no callback is attached to the given hook.
+     */
+    public function testShouldReturnFalseWhenNoCallbackAttached() {
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->hasCallback('the_content'));
+    }
+
+    /**
+     * Test should return true when a callback is attached to the given hook.
+     */
+    public function testShouldReturnTrueWhenCallbackAttached() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->hasCallback('the_content', null));
+    }
+
+    /**
+     * Test should return false when the given callback is not attached to the given hook.
+     */
+    public function testShouldReturnFalseWhenCallbackNotAttached() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->hasCallback('the_content', 'strtoupper'));
+    }
+
+    /**
+     * Test should return true when the given callback is attached to the given hook.
+     */
+    public function testShouldReturnPriorityIntWhenCallbackAttached() {
+        add_filter('the_content', 'strtolower', 11);
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->hasCallback('the_content', 'strtolower'));
+    }
+}
diff --git a/tests/Unit/PluginApiManager/removeCallback.php b/tests/Unit/PluginApiManager/removeCallback.php
new file mode 100644
index 0000000..556f616
--- /dev/null
+++ b/tests/Unit/PluginApiManager/removeCallback.php
@@ -0,0 +1,58 @@
+<?php
+
+namespace WPMedia\EventManager\Tests\Unit\PluginApiManager;
+
+use WPMedia\EventManager\Tests\Unit\TestCase;
+use WPMedia\EventManager\PluginApiManager;
+
+/**
+ * Tests for the removeCallback method
+ *
+ * @covers WPMedia\EventManager\PluginApiManager::removeCallback
+ * @group PluginApiManager
+ */
+class Test_RemoveCallback extends TestCase {
+    /**
+     * Test should return true when the given callback is removed from the given hook
+     */
+    public function testShouldReturnTrueWhenCallbackRemoved() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->removeCallback('the_content', 'strtolower'));
+    }
+
+    /**
+     * Test should return false when the given callback doesn't exist for the given hook
+     */
+    public function testShouldReturnFalseWhenCallbackDoesNotExist() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->removeCallback('the_content', 'strtoupper'));
+    }
+
+    /**
+     * Test should return false when the given callback priority doesn't match with the priority when added
+     */
+    public function testShouldReturnFalseWhenPriorityDoesNotMatch() {
+        add_filter('the_content', 'strtolower');
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertFalse($plugin_api_manager->removeCallback('the_content', 'strtolower', 100));
+    }
+
+    /**
+     * Test should return true when the given callback priority matches with the priority when added
+     */
+    public function testShouldReturnTrueWhenPriorityMatches() {
+        add_filter('the_content', 'strtolower', 100);
+
+        $plugin_api_manager = new PluginApiManager();
+
+        $this->assertTrue($plugin_api_manager->removeCallback('the_content', 'strtolower', 100));
+    }
+}
diff --git a/tests/Unit/TestCase.php b/tests/Unit/TestCase.php
new file mode 100644
index 0000000..706b8b8
--- /dev/null
+++ b/tests/Unit/TestCase.php
@@ -0,0 +1,33 @@
+<?php
+/**
+ * Test Case for all of the unit tests.
+ *
+ * @package WPMedia\EventManager\Tests\Unit
+ */
+
+namespace WPMedia\EventManager\Tests\Unit;
+
+use PHPUnit\Framework\TestCase as PHPUnitTestCase;
+use Brain\Monkey;
+use WPMedia\EventManager\Tests\TestCaseTrait;
+
+abstract class TestCase extends PHPUnitTestCase {
+    use \Mockery\Adapter\Phpunit\MockeryPHPUnitIntegration;
+    use TestCaseTrait;
+
+    /**
+     * Prepares the test environment before each test.
+     */
+    protected function setUp() {
+        parent::setUp();
+        Monkey\setUp();
+    }
+
+    /**
+     * Cleans up the test environment after each test.
+     */
+    protected function tearDown() {
+        Monkey\tearDown();
+        parent::tearDown();
+    }
+}
diff --git a/tests/Unit/bootstrap.php b/tests/Unit/bootstrap.php
new file mode 100644
index 0000000..1d22779
--- /dev/null
+++ b/tests/Unit/bootstrap.php
@@ -0,0 +1,13 @@
+<?php
+/**
+ * Bootstraps the plugin's Unit Tests
+ *
+ * @package WPMedia\EventManager\Tests\Unit
+ */
+
+namespace WPMedia\EventManager\Tests\Unit;
+
+use function WPMedia\EventManager\Tests\init_test_suite;
+
+require_once dirname( dirname( __FILE__ ) ) . '/bootstrap-functions.php';
+init_test_suite( 'Unit' );
\ No newline at end of file
diff --git a/tests/Unit/phpunit.xml.dist b/tests/Unit/phpunit.xml.dist
new file mode 100644
index 0000000..c8a641a
--- /dev/null
+++ b/tests/Unit/phpunit.xml.dist
@@ -0,0 +1,28 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:noNamespaceSchemaLocation="https://schema.phpunit.de/6.3/phpunit.xsd"
+         bootstrap="bootstrap.php"
+         backupGlobals="false"
+         colors="true"
+         beStrictAboutCoversAnnotation="true"
+         beStrictAboutOutputDuringTests="true"
+         beStrictAboutTestsThatDoNotTestAnything="true"
+         beStrictAboutTodoAnnotatedTests="true"
+         convertErrorsToExceptions="true"
+         convertNoticesToExceptions="true"
+         convertWarningsToExceptions="true"
+         verbose="true">
+
+    <testsuites>
+        <testsuite name="unit">
+            <directory suffix=".php">.</directory>
+            <exclude>TestCase.php</exclude>
+        </testsuite>
+    </testsuites>
+
+    <filter>
+        <whitelist processUncoveredFilesFromWhitelist="true">
+            <directory suffix=".php">.</directory>
+        </whitelist>
+    </filter>
+</phpunit>
\ No newline at end of file
diff --git a/tests/bootstrap-functions.php b/tests/bootstrap-functions.php
new file mode 100644
index 0000000..8e4c114
--- /dev/null
+++ b/tests/bootstrap-functions.php
@@ -0,0 +1,48 @@
+<?php
+/**
+ * Common bootstrap functionality.
+ *
+ * @package WPMedia\EventManager\Tests
+ */
+
+namespace WPMedia\EventManager\Tests;
+
+/**
+ * Initialize the test suite.
+ *
+ * @param string $test_suite Directory name of the test suite. Default is 'Unit'.
+ */
+function init_test_suite( $test_suite = 'Unit' ) {
+    check_readiness();
+    init_constants( $test_suite );
+    // Load the Composer autoloader.
+    require_once EVENTMANAGER_PLUGIN_ROOT . '/vendor/autoload.php';
+    require_once __DIR__ . '/TestCaseTrait.php';
+    // Load Patchwork before everything else in order to allow us to redefine WordPress, 3rd party, and WP Rocket functions.
+    require_once EVENTMANAGER_PLUGIN_ROOT . '/vendor/antecedent/patchwork/Patchwork.php';
+}
+
+/**
+ * Check the system's readiness to run the tests.
+ */
+function check_readiness() {
+    if ( version_compare( phpversion(), '5.6.0', '<' ) ) {
+        trigger_error( 'WP Rocket Unit Tests require PHP 5.6 or higher.', E_USER_ERROR ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error -- Valid use case for our testing suite.
+    }
+    if ( ! file_exists( dirname( __DIR__ ) . '/vendor/autoload.php' ) ) {
+        trigger_error( 'Whoops, we need Composer before we start running tests.  Please type: `composer install`.  When done, try running `phpunit` again.', E_USER_ERROR ); // phpcs:ignore WordPress.PHP.DevelopmentFunctions.error_log_trigger_error -- Valid use case for our testing suite.
+    }
+}
+
+/**
+ * Initialize the constants.
+ *
+ * @param string $test_suite_folder Directory name of the test suite.
+ */
+function init_constants( $test_suite_folder ) {
+    define( 'EVENTMANAGER_PLUGIN_ROOT', dirname( __DIR__ ) . DIRECTORY_SEPARATOR );
+    define( 'EVENTMANAGER_PLUGIN_TESTS_ROOT', __DIR__ . DIRECTORY_SEPARATOR . $test_suite_folder );
+    if ( 'Unit' === $test_suite_folder && ! defined( 'ABSPATH' ) ) {
+        define( 'ABSPATH', EVENTMANAGER_PLUGIN_ROOT );
+    }
+}