Index: src/wp-includes/wp-db.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/wp-includes/wp-db.php	(revision 40284)
+++ src/wp-includes/wp-db.php	(revision )
@@ -3330,11 +3330,17 @@
 	 * @return null|string Null on failure, version number on success.
 	 */
 	public function db_version() {
-		if ( $this->use_mysqli ) {
-			$server_info = mysqli_get_server_info( $this->dbh );
-		} else {
-			$server_info = mysql_get_server_info( $this->dbh );
+		return preg_replace( '/[^0-9.].*/', '', $this->db_server_info() );
-		}
+	}
-		return preg_replace( '/[^0-9.].*/', '', $server_info );
+
+    /**
+     * Retrieves full MySQL server information
+     *
+     * @return null|string Null on failure, server info on success.
+     */
+	public function db_server_info() {
+	    return $this->use_mysqli ?
+            mysqli_get_server_info( $this->dbh ) :
+            mysql_get_server_info( $this->dbh );
-	}
+    }
 }
Index: tests/phpunit/tests/db/charset.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- tests/phpunit/tests/db/charset.php	(revision 40284)
+++ tests/phpunit/tests/db/charset.php	(revision )
@@ -28,11 +28,7 @@
 
 		self::$_wpdb = new wpdb_exposed_methods_for_testing();
 
-		if ( self::$_wpdb->use_mysqli ) {
-			self::$server_info = mysqli_get_server_info( self::$_wpdb->dbh );
-		} else {
-			self::$server_info = mysql_get_server_info( self::$_wpdb->dbh );
-		}
+        self::$server_info = self::$_wpdb->db_server_info();
 	}
 
 	/**