device: allow to use dummy as a way to test streamer

This adds loopback tests via `tests/`

tests/dummy.sh

@@ -0,0 +1,49 @@
+#!/bin/bash
+
+if [[ $# -lt 1 ]]; then
+  echo "usage: $0 <input-file> [camera-streamer options]"
+  echo
+  echo "examples:"
+  echo "  $0 tests/capture.jpeg"
+  echo "  $0 tests/capture.jpeg --video-height=720"
+  echo "  $0 tests/capture.jpeg --snapshot-height=720 --video-height=480"
+  echo "  $0 tests/capture.h264"
+  exit 1
+fi
+
+INPUT=$(realpath "$1")
+shift
+
+case "$INPUT" in
+  *.jpeg)
+    set -- --camera-format=JPEG --camera-width=1920 --camera-height=1080 "$@"
+    ;;
+
+  *.yuv420)
+    set -- --camera-format=YUV420 --camera-width=1920 --camera-height=1080 "$@"
+    ;;
+
+  *.h264)
+    set -- --camera-format=H264 --camera-width=1920 --camera-height=1080 "$@"
+    ;;
+
+  *.bg10p)
+    set -- --camera-format=BG10P --camera-width=2304 --camera-height=1296 "$@"
+    ;;
+
+  *)
+    echo "$0: undefined format for $INPUT."
+    exit 1
+esac
+
+SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
+cd "$SCRIPT_DIR/.."
+
+set -xeo pipefail
+make -j$(nproc)
+
+exec ./camera-streamer \
+  --camera-type=dummy \
+  --camera-path="$INPUT" \
+  --camera.snapshot-height=1080 \
+  "$@"