fix(active-storage): don't fail on analyzing a blob derivated by watermark

Quand l'analyse du job se produit après le watermark, elle doit comparer
le checksum avec celui du fichier filigrané.

app/jobs/titre_identite_watermark_job.rb

@@ -19,8 +19,9 @@ class TitreIdentiteWatermarkJob < ApplicationJob
         processed = WatermarkService.new.process(file, output)
         return if processed.blank?
 
-        blob.upload(processed)
-        blob.touch(:watermarked_at)
+        blob.upload(processed) # also update checksum & byte_size accordingly
+        blob.watermarked_at = Time.current
+        blob.save!
       end
     end
   end

spec/jobs/titre_identite_watermark_job_spec.rb

@@ -0,0 +1,56 @@
+describe TitreIdentiteWatermarkJob, type: :job do
+  let(:blob) do
+    ActiveStorage::Blob.create_and_upload!(io: StringIO.new("toto"), filename: "toto.png")
+  end
+
+  let(:antivirus_pending) { false }
+  let(:watermark_service) { instance_double("WatermarkService") }
+
+  before do
+    virus_scanner_mock = instance_double("ActiveStorage::VirusScanner", pending?: antivirus_pending)
+    allow(blob).to receive(:virus_scanner).and_return(virus_scanner_mock)
+
+    allow(WatermarkService).to receive(:new).and_return(watermark_service)
+    allow(watermark_service).to receive(:process).and_return(true)
+  end
+
+  context "when watermark is already done" do
+    before do
+      allow(blob).to receive(:watermark_done?).and_return(true)
+    end
+
+    it "does not process the blob" do
+      expect(watermark_service).not_to receive(:process)
+      described_class.perform_now(blob)
+    end
+  end
+
+  context "when the blob is not scanned yet" do
+    let(:antivirus_pending) { true }
+
+    it "raises a FileNotScannedYetError" do
+      expect { described_class.perform_now(blob) }.to have_enqueued_job(described_class).with(blob)
+    end
+  end
+
+  context "when the blob is ready to be watermarked" do
+    let(:watermarked_file) { Tempfile.new("watermarked.png") }
+
+    before do
+      allow(watermarked_file).to receive(:size).and_return(100)
+    end
+
+    it "processes the blob with watermark" do
+      expect(watermark_service).to receive(:process).and_return(watermarked_file)
+
+      expect {
+        described_class.perform_now(blob)
+      }.to change {
+        blob.reload.checksum
+      }
+
+      expect(blob.byte_size).to eq(100)
+      expect(blob.watermarked_at).to be_present
+    end
+  end
+end