diff --git a/Dockerfile.test b/Dockerfile.test
index 9a33b0731..4a77a00db 100644
--- a/Dockerfile.test
+++ b/Dockerfile.test
@@ -17,6 +17,12 @@ RUN pip install --no-cache-dir -r requirements.txt -r requirements-dev.txt
 COPY backend/ ./backend/
 COPY pyproject.toml ./
 
+# Embedded GCode viewer assets — required so the @app.get("/gcode-viewer/...")
+# packaging-regression test in tests/integration/test_gcode_viewer.py actually
+# runs instead of pytest-skipping with "index.html not present". Path matches
+# the production Dockerfile (static_dir.parent / "gcode_viewer" = /app/gcode_viewer/).
+COPY gcode_viewer/ ./gcode_viewer/
+
 # Create necessary directories
 RUN mkdir -p /app/data /app/logs /app/archive