Common::getSniffCode(): throw exception on invalid input [2a]

Previously, if an invalid (incomplete) class name was passed, the `Common::getSniffCode()` method would return a garbled name, like `.Qualified.C`, which is just confusing.

This commit changes the behaviour to throw an `InvalidArgumentException` instead.

Includes test.

Author: jrfnl

src/Util/Common.php

@@ -616,6 +616,7 @@ public static function suggestType($varType)
      * @return string
      *
      * @throws \InvalidArgumentException When $sniffClass is not a non-empty string.
+     * @throws \InvalidArgumentException When $sniffClass is not a FQN for a sniff(test) class.
      */
     public static function getSniffCode($sniffClass)
     {
@@ -624,6 +625,12 @@ public static function getSniffCode($sniffClass)
         }
 
         $parts = explode('\\', $sniffClass);
+        if (count($parts) < 4) {
+            throw new InvalidArgumentException(
+                'The $sniffClass parameter was not passed a fully qualified sniff class name. Received: '.$sniffClass
+            );
+        }
+
         $sniff = array_pop($parts);
 
         if (substr($sniff, -5) === 'Sniff') {

tests/Core/Util/Common/GetSniffCodeTest.php

@@ -66,6 +66,52 @@ public static function dataGetSniffCodeThrowsExceptionOnInvalidInput()
     }//end dataGetSniffCodeThrowsExceptionOnInvalidInput()
 
 
+    /**
+     * Test receiving an expected exception when the $sniffClass parameter is not passed a value which
+     * could be a fully qualified sniff(test) class name.
+     *
+     * @param string $input String input which can not be a fully qualified sniff(test) class name.
+     *
+     * @dataProvider dataGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass
+     *
+     * @return void
+     */
+    public function testGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass($input)
+    {
+        $exception = 'InvalidArgumentException';
+        $message   = 'The $sniffClass parameter was not passed a fully qualified sniff class name. Received:';
+
+        if (method_exists($this, 'expectException') === true) {
+            // PHPUnit 5+.
+            $this->expectException($exception);
+            $this->expectExceptionMessage($message);
+        } else {
+            // PHPUnit 4.
+            $this->setExpectedException($exception, $message);
+        }
+
+        Common::getSniffCode($input);
+
+    }//end testGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass()
+
+
+    /**
+     * Data provider.
+     *
+     * @see testGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass()
+     *
+     * @return array<string, array<string>>
+     */
+    public static function dataGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass()
+    {
+        return [
+            'Unqualified class name'                       => ['ClassName'],
+            'Fully qualified class name, not enough parts' => ['Fully\\Qualified\\ClassName'],
+        ];
+
+    }//end dataGetSniffCodeThrowsExceptionOnInputWhichIsNotASniffTestClass()
+
+
     /**
      * Test transforming a sniff class name to a sniff code.
      *