Use custom exceptions

Use InvalidArgumentException for the invalid argument case, and
introduce a new CommandException class for the rest.

Author: danmichaelo

src/Command.php

@@ -23,7 +23,7 @@ private function __construct()
     public static function exec($command, array $params = array())
     {
         if (empty($command)) {
-            throw new \Exception('Command line is empty');
+            throw new \InvalidArgumentException('Command line is empty');
         }
 
         $command = self::bindParams($command, $params);
@@ -37,7 +37,7 @@ public static function exec($command, array $params = array())
         }
 
         if ($code !== 0) {
-            throw new \Exception($output . ' Command line: ' . $command);
+            throw new CommandException($command, $output, $code);
         }
 
         return $output;

src/CommandException.php

@@ -0,0 +1,39 @@
+<?php
+namespace pastuhov\Command;
+
+class CommandException extends \RuntimeException
+{
+    protected $command;
+    protected $output;
+    protected $returnCode;
+
+    public function __construct($command, $output, $returnCode)
+    {
+        $this->command = $command;
+        $this->output = $output;
+        $this->returnCode = $returnCode;
+
+        if ($this->returnCode == 127) {
+            $message = 'Command not found: "' . $this->getCommand() . '"';
+        } else {
+            $message = 'Command "' . $this->getCommand() . '" exited with code ' . $this->getReturnCode() . ': ' . $this->getOutput();
+        }
+
+        parent::__construct($message);
+    }
+
+    public function getCommand()
+    {
+        return $this->command;
+    }
+
+    public function getOutput()
+    {
+        return $this->output;
+    }
+
+    public function getReturnCode()
+    {
+        return $this->returnCode;
+    }
+}

tests/CommandTest.php

@@ -31,7 +31,7 @@ public function testExec()
      */
     public function testExecException()
     {
-        $this->setExpectedException('Exception');
+        $this->setExpectedException('pastuhov\Command\CommandException');
 
         $output = Command::exec(
             'echo111'
@@ -43,7 +43,7 @@ public function testExecException()
      */
     public function testExecEmptyCommand()
     {
-        $this->setExpectedException('Exception');
+        $this->setExpectedException('InvalidArgumentException');
 
         $output = Command::exec(
             ''