Rename configuration variable from START_SQL_SERVER to SQL_ENGINE, and use strings for better readability during CI.

.github/workflows/ci-bats-unix.yaml

@@ -22,7 +22,7 @@ jobs:
       fail-fast: true
       matrix:
         os: [ ubuntu-22.04, macos-latest ]
-        start_sql_server: [ true, false ]
+        sql_engine: [ remote-engine, local-engine ]
     env:
       use_credentials: ${{ secrets.AWS_SECRET_ACCESS_KEY != '' && secrets.AWS_ACCESS_KEY_ID != '' }}
     steps:
@@ -111,7 +111,7 @@ jobs:
         run: expect -v
       - name: Test all Unix
         env:
-          START_SQL_SERVER: ${{ matrix.start_sql_server }}
+          SQL_ENGINE: ${{ matrix.sql-engine }}
           PARQUET_RUNTIME_JAR: ${{ steps.parquet_cli.outputs.runtime_jar }}
           BATS_TEST_RETRIES: "3"
         run: |

integration-tests/bats/helper/local-remote.bash

@@ -143,7 +143,7 @@ EOM
 
 setup_remote_server() {
   script_name=$(basename ${BATS_TEST_FILENAME})
-  if [ "$START_SQL_SERVER" = "true" ];
+  if [ "$SQL_ENGINE" = "remote-engine" ];
   then
     if [[ "$SKIP_SERVER_TESTS" =~ "$script_name" ]];
     then
@@ -156,7 +156,7 @@ setup_remote_server() {
 }
 
 teardown_remote_server() {
-  if [ "$START_SQL_SERVER" = "true" ];
+  if [ "$SQL_ENGINE" = "remote-engine" ];
   then
     stop_sql_server
   fi