Clarify exception types and move formatting logic out of Loader

src/AppFile/FileNotFound.php

@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+namespace Cjm\Behat\Psr7Extension\AppFile;
+
+use Cjm\Behat\Psr7Extension\Psr7LoaderException;
+
+final class FileNotFound extends Psr7LoaderException
+{
+    public function __construct(string $path)
+    {
+        parent::__construct('File not found at ' . $path);
+    }
+}

src/AppFile/InvalidFile.php

@@ -0,0 +1,14 @@
+<?php
+declare(strict_types=1);
+
+namespace Cjm\Behat\Psr7Extension\AppFile;
+
+use Cjm\Behat\Psr7Extension\Psr7LoaderException;
+
+final class InvalidFile extends Psr7LoaderException
+{
+    public function __construct(string $path)
+    {
+        parent::__construct('File at ' . $path . ' did not return an application');
+    }
+}

src/AppFile/Loader.php

@@ -21,31 +21,29 @@ public function __construct(Psr7AppFactory ...$factories)
 
     public function load(string $path): Psr7App
     {
-        if (!file_exists($path)) {
-            throw new LoaderException('No file found at ' . $path);
-        }
-
-        if (!($type = include $path)) {
-            throw new LoaderException('File at ' . $path . ' did not return');
-        }
+        $type = $this->loadFromFile($path);
 
         foreach ($this->factories as $factory) {
             if ($app = $factory->createFrom($type)) {
                 return $app;
             }
         }
 
-        throw new LoaderException('Do not know how to create an app from ' . $this->type($type));
+        throw new UnknownType($type);
     }
 
-    private function type($type) : string
+    private function loadFromFile(string $path)
     {
-        $str = gettype($type);
+        if (!file_exists($path)) {
+            throw new FileNotFound($path);
+        }
+
+        $type = include $path;
 
-        if ($str == 'object') {
-            $str = 'object:' . get_class($type);
+        if (1 === $type) {
+            throw new InvalidFile($path);
         }
 
-        return $str;
+        return $type;
     }
 }

src/AppFile/UnknownType.php

@@ -0,0 +1,26 @@
+<?php
+declare(strict_types=1);
+
+namespace Cjm\Behat\Psr7Extension\AppFile;
+
+use Cjm\Behat\Psr7Extension\Psr7LoaderException;
+
+final class UnknownType extends Psr7LoaderException
+{
+    public function __construct($type)
+    {
+        parent::__construct('Do not know how to create an app from ' . $this->printableType($type));
+    }
+
+    private function printableType($type) : string
+    {
+        $str = gettype($type);
+
+        if ($str == 'object') {
+            $str = 'object:' . get_class($type);
+        }
+
+        return $str;
+    }
+
+}

src/Psr7LoaderException.php

@@ -0,0 +1,8 @@
+<?php
+declare(strict_types=1);
+
+namespace Cjm\Behat\Psr7Extension;
+
+abstract class Psr7LoaderException extends \InvalidArgumentException
+{
+}

tests/AppFile/LoaderTest.php

@@ -21,16 +21,16 @@ function setUp()
 
     function testItComplainsIfFileDoesNotExist()
     {
-        $this->expectException(LoaderException::class);
+        $this->expectException(FileNotFound::class);
 
         $this->loader->load(self::TMP_APP_FILE);
     }
 
-    function testItThrowsExceptionIfFileReturnsNull()
+    function testItThrowsExceptionIfFileDoesNotReturn()
     {
-        $this->expectException(LoaderException::class);
+        $this->expectException(InvalidFile::class);
 
-        file_put_contents(self::TMP_APP_FILE, '<?php return null;');
+        file_put_contents(self::TMP_APP_FILE, '<?php ');
 
         $this->loader->load(self::TMP_APP_FILE);
     }
@@ -39,7 +39,7 @@ function testItThrowsExceptionIfNoFactoryCanMakeApp()
     {
         file_put_contents(self::TMP_APP_FILE, '<?php return "no idea";');
 
-        $this->expectException(LoaderException::class);
+        $this->expectException(UnknownType::class);
 
         $this->loader->load(self::TMP_APP_FILE);
     }