Start Amp only if PHP-Scoper is used (box-project#171)

Starting Amp has an overhead and increase the likelyhood of rising an issue due to how Amp works. As
a result, it is better to not have to start it unless necessary. So far the current compactors are
fast enough to not require parallel processing, the build from Box without PHP-Scoper goes from 5s
with parallel processing to 3s without.

Closes box-project#135

src/Box.php

@@ -338,7 +338,7 @@ private function processContents(array $files, string $cwd): array
             return [$local, $processedContents];
         };
 
-        return is_parallel_processing_enabled()
+        return is_parallel_processing_enabled() && false === ($this->scoper instanceof NullScoper)
             ? wait(parallelMap($files, $processFile))
             : array_map($processFile, $files)
         ;

tests/BoxTest.php

@@ -14,7 +14,6 @@
 
 namespace KevinGH\Box;
 
-use Amp\MultiReasonException;
 use Exception;
 use InvalidArgumentException;
 use KevinGH\Box\Compactor\FakeCompactor;
@@ -768,7 +767,7 @@ public function test_the_temporary_directory_created_for_box_is_removed_upon_fai
             $this->box->addFiles(['/nowhere/foo'], false);
 
             $this->fail('Expected exception to be thrown.');
-        } catch (MultiReasonException $exception) {
+        } catch (InvalidArgumentException $exception) {
             $tmpDirs = iterator_to_array(
                 Finder::create()
                     ->directories()
@@ -777,20 +776,20 @@ public function test_the_temporary_directory_created_for_box_is_removed_upon_fai
             );
 
             $boxDir = current(
-                    array_filter(
-                            $tmpDirs,
-                            function (SplFileInfo $fileInfo) use ($boxTmp): bool {
-                                return false === in_array(
-                                            $fileInfo->getRealPath(),
-                                            [realpath($boxTmp), realpath($this->tmp)],
-                            true
-                                    );
-                            }
+                array_filter(
+                    $tmpDirs,
+                    function (SplFileInfo $fileInfo) use ($boxTmp): bool {
+                        return false === in_array(
+                            $fileInfo->getRealPath(),
+                            [realpath($boxTmp), realpath($this->tmp)],
+                        true
+                        );
+                    }
                 )
             );
 
             $this->assertFalse(
-                    $boxDir,
+                $boxDir,
                 sprintf(
                         'Did not expect to find the directory "%s".',
                     $boxDir

tests/Console/Command/CompileTest.php

@@ -14,10 +14,9 @@
 
 namespace KevinGH\Box\Console\Command;
 
-use Amp\MultiReasonException;
-use Amp\Parallel\Worker\TaskException;
 use DirectoryIterator;
 use Generator;
+use InvalidArgumentException;
 use KevinGH\Box\Compactor\Php;
 use KevinGH\Box\Console\DisplayNormalizer;
 use KevinGH\Box\Test\CommandTestCase;
@@ -33,10 +32,13 @@
 use function preg_replace;
 use function sort;
 
+///**
+// * @covers \KevinGH\Box\Console\Command\Compile
+// * @runTestsInSeparateProcesses This is necessary as instantiating a PHAR in memory may load/autoload some stuff which
+// *                              can create undesirable side-effects.
+// */
 /**
- * @covers \KevinGH\Box\Console\Command\Compile
- * @runTestsInSeparateProcesses This is necessary as instantiating a PHAR in memory may load/autoload some stuff which
- *                              can create undesirable side-effects.
+ * @coversNothing
  */
 class CompileTest extends CommandTestCase
 {
@@ -408,6 +410,8 @@ public function test_it_can_build_a_PHAR_without_any_configuration(): void
 
         $this->assertEquals($expectedFiles, $actualFiles, '', .0, 10, true);
 
+        unset($phar);
+        Phar::unlinkArchive('index.phar');
         // Executes the compilation again
 
         $commandTester->execute(
@@ -1103,15 +1107,10 @@ public function test_it_cannot_build_a_PHAR_using_unreadable_files(): void
             );
 
             $this->fail('Expected exception to be thrown.');
-        } catch (MultiReasonException $exception) {
-            $this->assertCount(1, $exception->getReasons());
-
-            /** @var TaskException $reason */
-            $reason = current($exception->getReasons());
-
+        } catch (InvalidArgumentException $exception) {
             $this->assertRegExp(
-                '/^Uncaught .+?ArgumentException in worker with message ".+?" was expected to be readable\.".*$/',
-                $reason->getMessage()
+                '/^Path ".+?" was expected to be readable\.$/',
+                $exception->getMessage()
             );
         }
     }