--- /dev/null
+<?php
+/*
+ * This file is part of the Comparator package.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace SebastianBergmann\Comparator;
+
+use SebastianBergmann\Exporter\Exporter;
+
+/**
+ * Abstract base class for comparators which compare values for equality.
+ */
+abstract class Comparator
+{
+ /**
+ * @var Factory
+ */
+ protected $factory;
+
+ /**
+ * @var Exporter
+ */
+ protected $exporter;
+
+ public function __construct()
+ {
+ $this->exporter = new Exporter;
+ }
+
+ /**
+ * @param Factory $factory
+ */
+ public function setFactory(Factory $factory)
+ {
+ $this->factory = $factory;
+ }
+
+ /**
+ * Returns whether the comparator can compare two values.
+ *
+ * @param mixed $expected The first value to compare
+ * @param mixed $actual The second value to compare
+ * @return bool
+ */
+ abstract public function accepts($expected, $actual);
+
+ /**
+ * Asserts that two values are equal.
+ *
+ * @param mixed $expected First value to compare
+ * @param mixed $actual Second value to compare
+ * @param float $delta Allowed numerical distance between two values to consider them equal
+ * @param bool $canonicalize Arrays are sorted before comparison when set to true
+ * @param bool $ignoreCase Case is ignored when set to true
+ *
+ * @throws ComparisonFailure
+ */
+ abstract public function assertEquals($expected, $actual, $delta = 0.0, $canonicalize = false, $ignoreCase = false);
+}