Implement "IfLess" helper

src/Comparison/IfLessHelper.php

@@ -0,0 +1,47 @@
+<?php
+/*
+ * This file is part of Handlebars.php Helpers Set
+ *
+ * (c) Dmitriy Simushev <simushevds@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace JustBlackBird\HandlebarsHelpers\Comparison;
+
+use Handlebars\Helper as HelperInterface;
+
+/**
+ * Conditional helper that checks if one value is less than another one.
+ *
+ * My "less" strict inequality is meant. That's why in cases where two equal
+ * values are compared the result of the "less" operation is false.
+ *
+ * Example of usage:
+ * ```handlebars
+ *   {{#ifLess first second}}
+ *     The first argument is less than the second one.
+ *   {{else}}
+ *     The first argument is more or equal to the second one.
+ *   {{/ifLess}}
+ * ```
+ *
+ * @author Dmitriy Simushev <simushevds@gmail.com>
+ */
+class IfLessHelper extends AbstractComparisonHelper implements HelperInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    protected function evaluateCondition($args)
+    {
+        if (count($args) != 2) {
+            throw new \InvalidArgumentException(
+                '"ifLess" helper expects exactly two arguments.'
+            );
+        }
+
+        return ($args[0] < $args[1]);
+    }
+}

tests/Comparison/IfLessHelperTest.php

@@ -0,0 +1,90 @@
+<?php
+/*
+ * This file is part of Handlebars.php Helpers Set
+ *
+ * (c) Dmitriy Simushev <simushevds@gmail.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace JustBlackBird\HandlebarsHelpers\Tests\Comparison;
+
+use JustBlackBird\HandlebarsHelpers\Comparison\IfLessHelper;
+
+/**
+ * Test class for "ifLess" helper.
+ *
+ * @author Dmitriy Simushev <simushevds@gmail.com>
+ */
+class IfLessHelperTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * Tests conditions work as expected.
+     *
+     * @dataProvider conditionProvider
+     */
+    public function testCondition($value, $border, $is_less)
+    {
+        $helpers = new \Handlebars\Helpers(array('ifLess' => new IfLessHelper()));
+        $engine = new \Handlebars\Handlebars(array('helpers' => $helpers));
+
+        $this->assertEquals(
+            $engine->render(
+                '{{#ifLess value border}}true{{else}}false{{/ifLess}}',
+                array(
+                    'value' => $value,
+                    'border' => $border,
+                )
+            ),
+            $is_less ? 'true' : 'false'
+        );
+    }
+
+    /**
+     * A data provider for testCondition method.
+     */
+    public function conditionProvider()
+    {
+        return array(
+            // Less values with different types.
+            array(2, 10, true),
+            array("8", "12", true),
+            // Equal values with different types.
+            array(0, 0, false),
+            array("42", "42", false),
+            // Greater values with different types.
+            array(75, 10, false),
+            array("17", "2", false),
+        );
+    }
+
+    /**
+     * Tests that exception is thrown if wrong number of arguments is used.
+     *
+     * @expectedException InvalidArgumentException
+     * @dataProvider wrongArgumentsProvider
+     */
+    public function testArgumentsCount($template)
+    {
+        $helpers = new \Handlebars\Helpers(array('ifLess' => new IfLessHelper()));
+        $engine = new \Handlebars\Handlebars(array('helpers' => $helpers));
+
+        $engine->render($template, array());
+    }
+
+    /**
+     * A data provider for testArgumentsCount method.
+     */
+    public function wrongArgumentsProvider()
+    {
+        return array(
+            // Not enough arguments
+            array('{{#ifLess}}yes{{else}}no{{/ifLess}}'),
+            // Still not enough arguments
+            array('{{#ifLess 1}}yes{{else}}no{{/ifLess}}'),
+            // Too much arguments
+            array('{{#ifLess 1 2 3}}yes{{else}}no{{/ifLess}}'),
+        );
+    }
+}