Fail fast when a test validator is not installed

scripts/start-shared-test-validator.sh

@@ -11,6 +11,11 @@ TEST_VALIDATOR=$( cd "$(dirname "${BASH_SOURCE[0]}")/.." ; pwd -P )/.agave/activ
 TEST_VALIDATOR_LEDGER="$( cd "$(dirname "${BASH_SOURCE[0]}")/.." ; pwd -P )/test-ledger"
 FIXTURE_ACCOUNTS_DIR="$( cd "$(dirname "${BASH_SOURCE[0]}")/fixtures" ; pwd -P)"
 
+if [ ! -x "$TEST_VALIDATOR" ]; then
+    echo "ERROR: No test validator is installed. Install one using the following command: pnpm test:live-with-test-validator:setup" >&2
+    exit 1
+fi
+
 mkdir -p $LOCK_DIR
 
 (
@@ -38,4 +43,4 @@ mkdir -p $LOCK_DIR
   else
     echo "Leaving test validator (PID $validator_pid) running for other lock participants"
   fi
-) 200>$SHARED_LOCK_FILE
+) 200>$SHARED_LOCK_FILE