Sanitize Input for Price Variables

- Updated the model to automatically format the price
- Updated the samples to reflect the new changes
- More Unit Tests

tests/PayPal/Test/Validation/NumericValidatorTest.php

@@ -0,0 +1,61 @@
+<?php
+namespace PayPal\Test\Validation;
+
+use PayPal\Common\FormatConverter;
+use PayPal\Validation\NumericValidator;
+
+class NumericValidatorTest extends \PHPUnit_Framework_TestCase
+{
+
+    public static function positiveProvider()
+    {
+        return array(
+            array("0", "0.00"),
+            array(null, null),
+            array("01", "1.00"),
+            array("01.1", "1.10"),
+            array("10.0", "10.00"),
+            array("0.0", "0.00"),
+            array("00.00", "0.00"),
+            array("000.111", "0.11"),
+            array("000.0001", "0.00"),
+            array("-0.001", "0.00"),
+            array("-0", "0.00"),
+            array("-00.00", "0.00"),
+            array("-10.00", "-10.00"),
+            array("", null),
+            array("  ", null),
+            array(1.20, "1.20")
+        );
+    }
+
+    public static function invalidProvider()
+    {
+        return array(
+            array("01.j"),
+            array("j.10"),
+            array("empty"),
+            array("null")
+        );
+    }
+
+    /**
+     *
+     * @dataProvider positiveProvider
+     */
+    public function testValidate($input)
+    {
+        $this->assertTrue(NumericValidator::validate($input, "Test Value"));
+    }
+
+    /**
+     *
+     * @dataProvider invalidProvider
+     * @expectedException \InvalidArgumentException
+     */
+    public function testValidateException($input)
+    {
+       NumericValidator::validate($input, "Test Value");
+    }
+
+}