tests: unexpected output

tests/Visual/UnexpectedOutput.php

@@ -0,0 +1,43 @@
+<?php
+
+test('unexpected output', function (array $arguments) {
+    $snapshot = __DIR__.'/../.snapshots/unexpected-output.txt';
+
+    if (in_array('--parallel', $arguments)) {
+        $snapshot = __DIR__.'/../.snapshots/unexpected-output-parallel.txt';
+    }
+
+    $output = function () use ($arguments) {
+        $process = (new Symfony\Component\Process\Process(
+            array_merge(['php', 'bin/pest', 'tests/Fixtures/UnexpectedOutput.php'], $arguments),
+            null,
+            ['COLLISION_PRINTER' => 'DefaultPrinter', 'COLLISION_IGNORE_DURATION' => 'true', 'COLLISION_TEST' => true]
+        ));
+
+        $process->run();
+
+        return preg_replace('#\\x1b[[][^A-Za-z]*[A-Za-z]#', '', $process->getOutput());
+    };
+
+    if (getenv('REBUILD_SNAPSHOTS')) {
+        $outputContent = explode("\n", $output());
+        array_pop($outputContent);
+        array_pop($outputContent);
+        array_pop($outputContent);
+
+        if (in_array('--parallel', $arguments)) {
+            array_pop($outputContent);
+            array_pop($outputContent);
+        }
+
+        file_put_contents($snapshot, implode("\n", $outputContent));
+
+        $this->markTestSkipped('Snapshot rebuilt.');
+    }
+
+    expect($output())
+        ->toContain(file_get_contents($snapshot));
+})->with([
+    [['']],
+    [['--parallel']],
+])->skipOnWindows();