add getters to filesystem repository

src/Repositories/FilesystemRepository.php

@@ -50,4 +50,14 @@ public function all(): Collection
                 return $this->get($path);
             });
     }
+
+    public function getFilesystem(): Filesystem
+    {
+        return $this->filesystem;
+    }
+
+    public function getExtension(): string
+    {
+        return $this->extension;
+    }
 }

tests/Repositories/FilesystemRepositoryTest.php

@@ -2,6 +2,7 @@
 
 namespace Spatie\Sheets\Tests\Repositories;
 
+use Illuminate\Contracts\Filesystem\Filesystem;
 use PHPUnit\Framework\TestCase;
 use Spatie\Sheets\Repositories\FilesystemRepository;
 use Spatie\Sheets\Sheet;
@@ -64,4 +65,34 @@ public function it_can_get_null_on_non_existed_path()
 
         $this->assertNull($filesystemRepository->get('invalid_path'));
     }
+
+    /** @test */
+    public function it_can_return_instance_of_filesystem()
+    {
+        $filesystemRepository = new FilesystemRepository(
+            $this->createFactory(),
+            $this->createFilesystem()
+        );
+
+        $this->assertInstanceOf(Filesystem::class, $filesystemRepository->getFilesystem());
+    }
+
+    /** @test */
+    public function it_can_return_file_extension()
+    {
+        $filesystemRepository = new FilesystemRepository(
+            $this->createFactory(),
+            $this->createFilesystem()
+        );
+
+        $this->assertEquals('md', $filesystemRepository->getExtension());
+
+        $filesystemRepository = new FilesystemRepository(
+            $this->createFactory(),
+            $this->createFilesystem(),
+            'json'
+        );
+
+        $this->assertEquals('json', $filesystemRepository->getExtension());
+    }
 }