Add smoke test for unrar-arm64

tests/test.sh

@@ -0,0 +1,36 @@
+#!/bin/bash
+set -euo pipefail
+
+IMAGE="$1"
+FAILED=0
+PASSED=0
+
+TMPDIR="$(mktemp -d)"
+trap 'rm -rf "$TMPDIR"' EXIT
+
+docker run --rm --entrypoint /usr/bin/unrar "$IMAGE" > "$TMPDIR/output" 2>&1; RC=$?
+
+if grep -qiE "unrar|usage" "$TMPDIR/output"; then
+  echo "PASS: unrar prints usage info"
+  PASSED=$((PASSED + 1))
+else
+  echo "FAIL: unrar output unrecognized"
+  FAILED=$((FAILED + 1))
+fi
+
+# unrar displays help on stderr in some versions, check there too
+docker run --rm --entrypoint /usr/bin/unrar "$IMAGE" 2> "$TMPDIR/stderr" 1>/dev/null; :
+
+if grep -qiE "unrar|usage" "$TMPDIR/stderr"; then
+  echo "PASS: unrar stderr contains usage info"
+  PASSED=$((PASSED + 1))
+else
+  echo "FAIL: unrar stderr unrecognized"
+  FAILED=$((FAILED + 1))
+fi
+
+echo ""
+echo "$PASSED/$((PASSED + FAILED)) tests passed"
+if [ "$FAILED" -gt 0 ]; then
+  exit 1
+fi