test: Do not hide the original throwable stack trace when failing to parse a file

tests/Scoper/PhpScoperSpecTest.php

@@ -22,6 +22,7 @@
 use Humbug\PhpScoper\Container;
 use Humbug\PhpScoper\PhpParser\TraverserFactory;
 use Humbug\PhpScoper\Scoper\Spec\SpecFinder;
+use Humbug\PhpScoper\Scoper\Spec\UnparsableFile;
 use Humbug\PhpScoper\Symbol\EnrichedReflector;
 use Humbug\PhpScoper\Symbol\NamespaceRegistry;
 use Humbug\PhpScoper\Symbol\Reflector;
@@ -244,13 +245,7 @@ public static function provideValidFiles(): iterable
                     );
                 }
             } catch (Throwable $throwable) {
-                self::fail(
-                    sprintf(
-                        'An error occurred while parsing the file "%s": %s',
-                        $file,
-                        $throwable->getMessage(),
-                    ),
-                );
+                throw UnparsableFile::create($file, $throwable);
             }
         }
     }

tests/Scoper/Spec/UnparsableFile.php

@@ -0,0 +1,37 @@
+<?php
+
+declare(strict_types=1);
+
+/*
+ * This file is part of the humbug/php-scoper package.
+ *
+ * Copyright (c) 2017 Théo FIDRY <[email protected]>,
+ *                    Pádraic Brady <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Humbug\PhpScoper\Scoper\Spec;
+
+use DomainException;
+use SplFileInfo;
+use Throwable;
+use function sprintf;
+
+final class UnparsableFile extends DomainException
+{
+    public static function create(
+        SplFileInfo $file,
+        Throwable $throwable,
+    ): self {
+        return new self(
+            sprintf(
+                'An error occurred while parsing the file "%s": %s',
+                $file,
+                $throwable->getMessage(),
+            ),
+            previous: $throwable,
+        );
+    }
+}