Fix media attachment size validation not correctly accounting for file type (#16819)

* Fix media attachment size validation not correctly accounting for file type

Fixes a regression introduced in #16724 caused by the fact that kt-paperclip
now correctly runs validations before processing, meaning that file size
verification could not rely on our before_post_processing hook.

Moved the `before_post_processing` hooks to `before_validate` to make sure
the media attachment type is set correctly before the file gets validated.

* Add tests

1 files changed, 28 insertions, 0 deletions

diff --git a/spec/models/media_attachment_spec.rb b/spec/models/media_attachment_spec.rb
index edab67d47..5dbb3d206 100644
--- a/spec/models/media_attachment_spec.rb
+++ b/spec/models/media_attachment_spec.rb
@@ -181,4 +181,32 @@ RSpec.describe MediaAttachment, type: :model do
       expect(media.description.size).to be <= 1_500
     end
   end
+
+  describe 'size limit validation' do
+    it 'rejects video files that are too large' do
+      stub_const 'MediaAttachment::IMAGE_LIMIT', 100.megabytes
+      stub_const 'MediaAttachment::VIDEO_LIMIT', 1.kilobyte
+      expect { MediaAttachment.create!(account: Fabricate(:account), file: attachment_fixture('attachment.webm')) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    it 'accepts video files that are small enough' do
+      stub_const 'MediaAttachment::IMAGE_LIMIT', 1.kilobyte
+      stub_const 'MediaAttachment::VIDEO_LIMIT', 100.megabytes
+      media = MediaAttachment.create!(account: Fabricate(:account), file: attachment_fixture('attachment.webm'))
+      expect(media.valid?).to be true
+    end
+
+    it 'rejects image files that are too large' do
+      stub_const 'MediaAttachment::IMAGE_LIMIT', 1.kilobyte
+      stub_const 'MediaAttachment::VIDEO_LIMIT', 100.megabytes
+      expect { MediaAttachment.create!(account: Fabricate(:account), file: attachment_fixture('attachment.jpg')) }.to raise_error(ActiveRecord::RecordInvalid)
+    end
+
+    it 'accepts image files that are small enough' do
+      stub_const 'MediaAttachment::IMAGE_LIMIT', 100.megabytes
+      stub_const 'MediaAttachment::VIDEO_LIMIT', 1.kilobyte
+      media = MediaAttachment.create!(account: Fabricate(:account), file: attachment_fixture('attachment.jpg'))
+      expect(media.valid?).to be true
+    end
+  end
 end