Fix sporadic test failures in S3BackupService specs by mocking tar compression

spec/services/s3_backup_service_spec.rb

@@ -13,6 +13,22 @@
   let(:compressed_filename) { "database-#{timestamp}.tar.gz" }
   let(:s3_key) { "db_backups/#{compressed_filename}" }
 
+  # Helper method to mock tar compression and create the compressed file
+  def mock_tar_compression(service, content_size: 1000)
+    allow(service).to receive(:system).with(
+      "tar", "-czf", anything,
+      "-C", anything, anything,
+      exception: true
+    ) do |*args|
+      # Extract the destination path from the tar command arguments
+      dest_path = args[2]
+      # Create the compressed file that would be created by tar
+      FileUtils.touch(dest_path)
+      File.write(dest_path, "compressed content" * content_size)
+      true
+    end
+  end
+
   before do
     allow(Time).to receive(:current).and_return(Time.zone.parse("2024-01-15 10:00:00"))
     allow(ENV).to receive(:[]).and_call_original
@@ -86,15 +102,7 @@
         ).and_return(true)
 
         # Mock tar compression
-        allow(service).to receive(:system).with(
-          "tar", "-czf", anything,
-          "-C", anything, anything,
-          exception: true
-        ).and_return(true)
-
-        # Create mock compressed file
-        FileUtils.touch(temp_compressed_path)
-        File.write(temp_compressed_path, "compressed content" * 1000)
+        mock_tar_compression(service)
 
         # Mock S3 upload
         allow(s3_service).to receive(:upload)
@@ -338,13 +346,8 @@
           exception: true
         ).and_return(true)
 
-        allow(service).to receive(:system).with(
-          "tar", "-czf", /database-2025-12-31\.tar\.gz/,
-          "-C", anything, "database-2025-12-31.sqlite3",
-          exception: true
-        ).and_return(true)
-
-        FileUtils.touch(temp_compressed_path)
+        # Mock tar compression
+        mock_tar_compression(service)
         allow(s3_service).to receive(:upload)
         allow(bucket).to receive(:objects).and_return([])
 
@@ -358,8 +361,20 @@
       let(:temp_compressed_path) { temp_dir.join(compressed_filename) }
 
       before do
+        # Default stub for any system calls
         allow(service).to receive(:system).and_return(true)
-        FileUtils.touch(temp_compressed_path)
+
+        # Mock database backup creation
+        allow(service).to receive(:system).with(
+          "sqlite3",
+          anything,
+          /\.backup/,
+          exception: true
+        ).and_return(true)
+
+        # Mock tar compression
+        mock_tar_compression(service)
+
         allow(s3_service).to receive(:upload)
       end