diff --git a/.distignore b/.distignore
index b964b40c7..95b52fb02 100644
--- a/.distignore
+++ b/.distignore
@@ -6,6 +6,8 @@
 .travis.yml
 behat.yml
 circle.yml
+phpcs.xml.dist
+phpunit.xml.dist
 bin/
 features/
 utils/
diff --git a/.gitignore b/.gitignore
index ff4941991..bcf211b32 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,3 +6,6 @@ vendor/
 *.tar.gz
 composer.lock
 *.log
+phpunit.xml
+phpcs.xml
+.phpcs.xml
diff --git a/composer.json b/composer.json
index 09f2dff18..fd2519c7c 100644
--- a/composer.json
+++ b/composer.json
@@ -16,7 +16,7 @@
     },
     "require-dev": {
         "wp-cli/entity-command": "^1.3 || ^2",
-        "wp-cli/wp-cli-tests": "^2.0.11"
+        "wp-cli/wp-cli-tests": "^2.1"
     },
     "config": {
         "process-timeout": 7200,
diff --git a/cron-command.php b/cron-command.php
index eedb81eaa..96022abec 100644
--- a/cron-command.php
+++ b/cron-command.php
@@ -4,9 +4,9 @@
 	return;
 }
 
-$autoload = dirname( __FILE__ ) . '/vendor/autoload.php';
-if ( file_exists( $autoload ) ) {
-	require_once $autoload;
+$wpcli_cron_autoloader = dirname( __FILE__ ) . '/vendor/autoload.php';
+if ( file_exists( $wpcli_cron_autoloader ) ) {
+	require_once $wpcli_cron_autoloader;
 }
 
 WP_CLI::add_command( 'cron', 'Cron_Command' );
diff --git a/phpcs.xml.dist b/phpcs.xml.dist
new file mode 100644
index 000000000..4c5ea7966
--- /dev/null
+++ b/phpcs.xml.dist
@@ -0,0 +1,59 @@
+<?xml version="1.0"?>
+<ruleset name="WP-CLI-cron">
+	<description>Custom ruleset for WP-CLI cron-command</description>
+
+	<!--
+	#############################################################################
+	COMMAND LINE ARGUMENTS
+	For help understanding this file: https://github.com/squizlabs/PHP_CodeSniffer/wiki/Annotated-ruleset.xml
+	For help using PHPCS: https://github.com/squizlabs/PHP_CodeSniffer/wiki/Usage
+	#############################################################################
+	-->
+
+	<!-- What to scan. -->
+	<file>.</file>
+
+	<!-- Show progress. -->
+	<arg value="p"/>
+
+	<!-- Strip the filepaths down to the relevant bit. -->
+	<arg name="basepath" value="./"/>
+
+	<!-- Check up to 8 files simultaneously. -->
+	<arg name="parallel" value="8"/>
+
+	<!--
+	#############################################################################
+	USE THE WP_CLI_CS RULESET
+	#############################################################################
+	-->
+
+	<rule ref="WP_CLI_CS"/>
+
+	<!--
+	#############################################################################
+	PROJECT SPECIFIC CONFIGURATION FOR SNIFFS
+	#############################################################################
+	-->
+
+	<!-- For help understanding the `testVersion` configuration setting:
+		 https://github.com/PHPCompatibility/PHPCompatibility#sniffing-your-code-for-compatibility-with-specific-php-versions -->
+	<config name="testVersion" value="5.4-"/>
+
+	<!-- Verify that everything in the global namespace is either namespaced or prefixed.
+		 See: https://github.com/WordPress-Coding-Standards/WordPress-Coding-Standards/wiki/Customizable-sniff-properties#naming-conventions-prefix-everything-in-the-global-namespace -->
+	<rule ref="WordPress.NamingConventions.PrefixAllGlobals">
+		<properties>
+			<property name="prefixes" type="array">
+				<element value="WP_CLI\Cron"/><!-- Namespaces. -->
+				<element value="wpcli_cron"/><!-- Global variables and such. -->
+			</property>
+		</properties>
+	</rule>
+
+	<!-- Exclude existing classes from the prefix rule as it would break BC to prefix them now. -->
+	<rule ref="WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedClassFound">
+		<exclude-pattern>*/src/Cron_(Event_|Schedule_)?Command\.php$</exclude-pattern>
+	</rule>
+
+</ruleset>
diff --git a/src/Cron_Command.php b/src/Cron_Command.php
index b93c86fa6..127186e71 100644
--- a/src/Cron_Command.php
+++ b/src/Cron_Command.php
@@ -69,15 +69,19 @@ protected static function get_cron_spawn() {
 		$sslverify     = \WP_CLI\Utils\wp_version_compare( 4.0, '<' );
 		$doing_wp_cron = sprintf( '%.22F', microtime( true ) );
 
-		$cron_request = apply_filters( 'cron_request', array(
+		$cron_request_array = array(
 			'url'  => site_url( 'wp-cron.php?doing_wp_cron=' . $doing_wp_cron ),
 			'key'  => $doing_wp_cron,
 			'args' => array(
 				'timeout'   => 3,
 				'blocking'  => true,
-				'sslverify' => apply_filters( 'https_local_ssl_verify', $sslverify )
-			)
-		) );
+				// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Calling native WordPress hook.
+				'sslverify' => apply_filters( 'https_local_ssl_verify', $sslverify ),
+			),
+		);
+
+		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Calling native WordPress hook.
+		$cron_request = apply_filters( 'cron_request', $cron_request_array );
 
 		# Enforce a blocking request in case something that's hooked onto the 'cron_request' filter sets it to false
 		$cron_request['args']['blocking'] = true;
diff --git a/src/Cron_Event_Command.php b/src/Cron_Event_Command.php
index fde3a77f0..3b76b300c 100644
--- a/src/Cron_Event_Command.php
+++ b/src/Cron_Event_Command.php
@@ -1,5 +1,7 @@
 <?php
 
+use WP_CLI\Utils;
+
 /**
  * Schedules, runs, and deletes WP-Cron events.
  *
@@ -31,6 +33,7 @@ class Cron_Event_Command extends WP_CLI_Command {
 		'next_run_relative',
 		'recurrence',
 	);
+
 	private static $time_format = 'Y-m-d H:i:s';
 
 	/**
@@ -112,7 +115,7 @@ public function list_( $args, $assoc_args ) {
 			}
 		}
 
-		if ( 'ids' == $formatter->format ) {
+		if ( 'ids' === $formatter->format ) {
 			echo implode( ' ', wp_list_pluck( $events, 'hook' ) );
 		} else {
 			$formatter->display_items( $events );
@@ -153,13 +156,13 @@ public function list_( $args, $assoc_args ) {
 	 */
 	public function schedule( $args, $assoc_args ) {
 
-		$hook = $args[0];
-		$next_run = \WP_CLI\Utils\get_flag_value( $args, 1, 'now' );
-		$recurrence = \WP_CLI\Utils\get_flag_value( $args, 2, false );
+		$hook       = $args[0];
+		$next_run   = Utils\get_flag_value( $args, 1, 'now' );
+		$recurrence = Utils\get_flag_value( $args, 2, false );
 
 		if ( empty( $next_run ) ) {
 			$timestamp = time();
-		} else if ( is_numeric( $next_run ) ) {
+		} elseif ( is_numeric( $next_run ) ) {
 			$timestamp = absint( $next_run );
 		} else {
 			$timestamp = strtotime( $next_run );
@@ -173,7 +176,7 @@ public function schedule( $args, $assoc_args ) {
 
 			$schedules = wp_get_schedules();
 
-			if ( ! isset( $schedules[$recurrence] ) ) {
+			if ( ! isset( $schedules[ $recurrence ] ) ) {
 				WP_CLI::error( sprintf( "'%s' is not a valid schedule name for recurrence.", $recurrence ) );
 			}
 
@@ -215,7 +218,7 @@ public function schedule( $args, $assoc_args ) {
 	 */
 	public function run( $args, $assoc_args ) {
 
-		if ( empty( $args ) && ! \WP_CLI\Utils\get_flag_value( $assoc_args, 'due-now' ) && ! \WP_CLI\Utils\get_flag_value( $assoc_args, 'all' ) ) {
+		if ( empty( $args ) && ! Utils\get_flag_value( $assoc_args, 'due-now' ) && ! Utils\get_flag_value( $assoc_args, 'all' ) ) {
 			WP_CLI::error( 'Please specify one or more cron events, or use --due-now/--all.' );
 		}
 
@@ -226,15 +229,15 @@ public function run( $args, $assoc_args ) {
 		}
 
 		$hooks = wp_list_pluck( $events, 'hook' );
-		foreach( $args as $hook ) {
+		foreach ( $args as $hook ) {
 			if ( ! in_array( $hook, $hooks, true ) ) {
 				WP_CLI::error( sprintf( "Invalid cron event '%s'", $hook ) );
 			}
 		}
 
-		if ( \WP_CLI\Utils\get_flag_value( $assoc_args, 'due-now' ) ) {
+		if ( Utils\get_flag_value( $assoc_args, 'due-now' ) ) {
 			$due_events = array();
-			foreach( $events as $event ) {
+			foreach ( $events as $event ) {
 				if ( ! empty( $args ) && ! in_array( $event->hook, $args, true ) ) {
 					continue;
 				}
@@ -243,10 +246,10 @@ public function run( $args, $assoc_args ) {
 				}
 			}
 			$events = $due_events;
-		} else if ( ! \WP_CLI\Utils\get_flag_value( $assoc_args, 'all' ) ) {
+		} elseif ( ! Utils\get_flag_value( $assoc_args, 'all' ) ) {
 			$due_events = array();
-			foreach( $events as $event ) {
-				if ( in_array( $event->hook, $args ) ) {
+			foreach ( $events as $event ) {
+				if ( in_array( $event->hook, $args, true ) ) {
 					$due_events[] = $event;
 				}
 			}
@@ -255,9 +258,9 @@ public function run( $args, $assoc_args ) {
 
 		$executed = 0;
 		foreach ( $events as $event ) {
-			$start = microtime( true );
+			$start  = microtime( true );
 			$result = self::run_event( $event );
-			$total = round( microtime( true ) - $start, 3 );
+			$total  = round( microtime( true ) - $start, 3 );
 			$executed++;
 			WP_CLI::log( sprintf( "Executed the cron event '%s' in %ss.", $event->hook, $total ) );
 		}
@@ -275,16 +278,18 @@ public function run( $args, $assoc_args ) {
 	protected static function run_event( stdClass $event ) {
 
 		if ( ! defined( 'DOING_CRON' ) ) {
+			// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedConstantFound -- Using native WordPress constant.
 			define( 'DOING_CRON', true );
 		}
 
-		if ( $event->schedule != false ) {
+		if ( false !== $event->schedule ) {
 			$new_args = array( $event->time, $event->schedule, $event->hook, $event->args );
 			call_user_func_array( 'wp_reschedule_event', $new_args );
 		}
 
 		wp_unschedule_event( $event->time, $event->hook, $event->args );
 
+		// phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.DynamicHooknameFound -- Can't prefix dynamic hooks here, calling registered hooks.
 		do_action_ref_array( $event->hook, $event->args );
 
 		return true;
@@ -316,7 +321,7 @@ public function delete( $args, $assoc_args ) {
 
 		$deleted = 0;
 		foreach ( $events as $event ) {
-			if ( $event->hook == $hook ) {
+			if ( $event->hook === $hook ) {
 				$result = self::delete_event( $event );
 				if ( $result ) {
 					$deleted++;
@@ -327,7 +332,7 @@ public function delete( $args, $assoc_args ) {
 		}
 
 		if ( $deleted ) {
-			$message = ( 1 == $deleted ) ? "Deleted the cron event '%2\$s'." : "Deleted %1\$d instances of the cron event '%2\$s'.";
+			$message = ( 1 === $deleted ) ? "Deleted the cron event '%2\$s'." : "Deleted %1\$d instances of the cron event '%2\$s'.";
 			WP_CLI::success( sprintf( $message, $deleted, $hook ) );
 		} else {
 			WP_CLI::error( sprintf( "Invalid cron event '%s'.", $hook ) );
@@ -344,7 +349,7 @@ public function delete( $args, $assoc_args ) {
 	protected static function delete_event( stdClass $event ) {
 		$crons = _get_cron_array();
 
-		if ( ! isset( $crons[$event->time][$event->hook][$event->sig] ) ) {
+		if ( ! isset( $crons[ $event->time ][ $event->hook ][ $event->sig ] ) ) {
 			return false;
 		}
 
@@ -395,7 +400,7 @@ protected static function get_cron_events() {
 						'sig'      => $sig,
 						'args'     => $data['args'],
 						'schedule' => $data['schedule'],
-						'interval' => \WP_CLI\Utils\get_flag_value( $data, 'interval' ),
+						'interval' => Utils\get_flag_value( $data, 'interval' ),
 					);
 
 				}
@@ -425,13 +430,13 @@ private static function interval( $since ) {
 
 		// array of time period chunks
 		$chunks = array(
-			array( 60 * 60 * 24 * 365 , \_n_noop( '%s year', '%s years' ) ),
-			array( 60 * 60 * 24 * 30 , \_n_noop( '%s month', '%s months' ) ),
-			array( 60 * 60 * 24 * 7, \_n_noop( '%s week', '%s weeks' ) ),
-			array( 60 * 60 * 24 , \_n_noop( '%s day', '%s days' ) ),
-			array( 60 * 60 , \_n_noop( '%s hour', '%s hours' ) ),
-			array( 60 , \_n_noop( '%s minute', '%s minutes' ) ),
-			array(  1 , \_n_noop( '%s second', '%s seconds' ) ),
+			array( 60 * 60 * 24 * 365, 'year' ),
+			array( 60 * 60 * 24 * 30, 'month' ),
+			array( 60 * 60 * 24 * 7, 'week' ),
+			array( 60 * 60 * 24, 'day' ),
+			array( 60 * 60, 'hour' ),
+			array( 60, 'minute' ),
+			array( 1, 'second' ),
 		);
 
 		// we only want to output two chunks of time here, eg:
@@ -441,26 +446,28 @@ private static function interval( $since ) {
 
 		// step one: the first chunk
 		for ( $i = 0, $j = count( $chunks ); $i < $j; $i++ ) {
-			$seconds = $chunks[$i][0];
-			$name = $chunks[$i][1];
+			$seconds = $chunks[ $i ][0];
+			$name    = $chunks[ $i ][1];
 
 			// finding the biggest chunk (if the chunk fits, break)
-			if ( ( $count = floor( $since / $seconds ) ) != 0 ){
+			$count = floor( $since / $seconds );
+			if ( floatval( 0 ) !== $count ) {
 				break;
 			}
 		}
 
 		// set output var
-		$output = sprintf( \_n( $name[0], $name[1], $count ), $count );
+		$output = sprintf( '%d %s', $count, Utils\pluralize( $name, absint( $count ) ) );
 
 		// step two: the second chunk
 		if ( $i + 1 < $j ) {
-			$seconds2 = $chunks[$i + 1][0];
-			$name2    = $chunks[$i + 1][1];
+			$seconds2 = $chunks[ $i + 1 ][0];
+			$name2    = $chunks[ $i + 1 ][1];
 
-			if ( ( $count2 = floor( ( $since - ( $seconds * $count ) ) / $seconds2 ) ) != 0 ) {
+			$count2 = floor( ( $since - ( $seconds * $count ) ) / $seconds2 );
+			if ( floatval( 0 ) !== $count2 ) {
 				// add to output var
-				$output .= ' ' . sprintf( \_n( $name2[0], $name2[1], $count2 ), $count2 );
+				$output .= ' ' . sprintf( '%d %s', $count2, Utils\pluralize( $name2, absint( $count2 ) ) );
 			}
 		}
 
diff --git a/src/Cron_Schedule_Command.php b/src/Cron_Schedule_Command.php
index 08e4eae2c..46d850ec4 100644
--- a/src/Cron_Schedule_Command.php
+++ b/src/Cron_Schedule_Command.php
@@ -79,7 +79,7 @@ public function list_( $args, $assoc_args ) {
 
 		$schedules = self::get_schedules();
 
-		if ( 'ids' == $formatter->format ) {
+		if ( 'ids' === $formatter->format ) {
 			echo implode( ' ', wp_list_pluck( $schedules, 'name' ) );
 		} else {
 			$formatter->display_items( $schedules );
@@ -106,7 +106,7 @@ protected static function format_schedule( array $schedule, $name ) {
 	*/
 	protected static function get_schedules() {
 		$schedules = wp_get_schedules();
-		if ( !empty( $schedules ) ) {
+		if ( ! empty( $schedules ) ) {
 			uasort( $schedules, 'Cron_Schedule_Command::sort' );
 			$schedules = array_map( 'Cron_Schedule_Command::format_schedule', $schedules, array_keys( $schedules ) );
 		}