Adding unit test for VariableAnalysis sniff

In #78 there is a fatal error reported in case the sniff is processing a `compact` function's args.

Author: david-binda

WordPressVIPMinimum/Tests/Variables/VariableAnalysisUnitTest.inc

@@ -0,0 +1,6 @@
+<?php
+
+function foo() {
+	$a = 'Hello';
+	$c = compact( $a, $b );
+}

WordPressVIPMinimum/Tests/Variables/VariableAnalysisUnitTest.php

@@ -0,0 +1,36 @@
+<?php
+/**
+ * Unit test class for WordPressVIPMinimum Coding Standard.
+ *
+ * @package VIPCS\WordPressVIPMinimum
+ */
+
+/**
+ * Unit test class for the Variable Analysis sniff.
+ *
+ * @package VIPCS\WordPressVIPMinimum
+ */
+class WordPressVIPMinimum_Tests_Variables_VariableAnalysisUnitTest extends AbstractSniffUnitTest {
+
+	/**
+	 * Returns the lines where errors should occur.
+	 *
+	 * @return array <int line number> => <int number of errors>
+	 */
+	public function getErrorList() {
+		return array();
+	}
+
+	/**
+	 * Returns the lines where warnings should occur.
+	 *
+	 * @return array <int line number> => <int number of warnings>
+	 */
+	public function getWarningList() {
+		return array(
+			5 => 2,
+		);
+
+	}
+
+} // End class.