Diff shows only changed lines (#3242)

Diff shows only changed lines

The diff used to show both complete strings instead of only the changed lines,
I've added a unit test for the case and refactored a bit inside the Console.php

composer.json

@@ -30,7 +30,9 @@
         "symfony/browser-kit": ">=2.7 <4.0",
         "symfony/css-selector": ">=2.7 <4.0",
         "symfony/dom-crawler": ">=2.7 <4.0",
-        "behat/gherkin": "~4.4.0"
+        "behat/gherkin": "~4.4.0",
+        "sebastian/comparator": "~1.1",
+        "sebastian/diff": "^1.4"
 
     },
     "require-dev": {

src/Codeception/Lib/Console/Colorizer.php

@@ -0,0 +1,38 @@
+<?php
+namespace Codeception\Lib\Console;
+
+/**
+ * Colorizer
+ **/
+class Colorizer
+{
+    /**
+     * @param string $string
+     * @return string
+     */
+    public function colorize($string = '')
+    {
+        $fp = fopen('php://memory', 'r+');
+        fwrite($fp, $string);
+        rewind($fp);
+
+        $colorizedMessage = '';
+        while ($line = fgets($fp)) {
+            $char = $line[0];
+            $line = trim($line);
+
+            switch ($char) {
+                case '+':
+                    $line = "<info>$line</info>";
+                    break;
+                case '-':
+                    $line = "<comment>$line</comment>";
+                    break;
+            }
+
+            $colorizedMessage .= $line . "\n";
+        }
+
+        return trim($colorizedMessage);
+    }
+}

src/Codeception/Lib/Console/DiffFactory.php

@@ -0,0 +1,41 @@
+<?php
+namespace Codeception\Lib\Console;
+
+use SebastianBergmann\Comparator\ComparisonFailure;
+use SebastianBergmann\Diff\Differ;
+
+/**
+ * DiffFactory
+ **/
+class DiffFactory
+{
+    /**
+     * @param ComparisonFailure $failure
+     * @return string|null
+     */
+    public function createDiff(ComparisonFailure $failure)
+    {
+        $diff = $this->getDiff($failure->getExpectedAsString(), $failure->getActualAsString());
+        if (!$diff) {
+            return null;
+        }
+
+        return $diff;
+    }
+
+    /**
+     * @param string $expected
+     * @param string $actual
+     * @return string
+     */
+    private function getDiff($expected = '', $actual = '')
+    {
+        if (!$actual && !$expected) {
+            return '';
+        }
+
+        $differ = new Differ('');
+
+        return $differ->diff($expected, $actual);
+    }
+}

src/Codeception/Lib/Console/MessageFactory.php

@@ -0,0 +1,53 @@
+<?php
+namespace Codeception\Lib\Console;
+
+use SebastianBergmann\Comparator\ComparisonFailure;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * MessageFactory
+ **/
+class MessageFactory
+{
+    /**
+     * @var DiffFactory
+     */
+    protected $diffFactory;
+    /**
+     * @var OutputInterface
+     */
+    private $output;
+
+    /**
+     * MessageFactory constructor.
+     * @param Output $output
+     */
+    public function __construct(Output $output)
+    {
+        $this->output = $output;
+        $this->diffFactory = new DiffFactory();
+        $this->colorizer = new Colorizer();
+    }
+
+    /**
+     * @param string $text
+     * @return Message
+     */
+    public function message($text = '')
+    {
+        return new Message($text, $this->output);
+    }
+
+    /**
+     * @param ComparisonFailure $failure
+     * @return Message|null
+     */
+    public function prepareComparisonFailureMessage(ComparisonFailure $failure)
+    {
+        $diff = $this->diffFactory->createDiff($failure);
+        $diff = $this->colorizer->colorize($diff);
+
+        return $this->message($diff)
+            ->prepend("<comment>- Expected</comment> | <info>+ Actual</info>\n");
+    }
+}