test: nit fixes

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/AbstractStatementParser.java

@@ -551,7 +551,7 @@ static int countOccurrencesOf(char c, String string) {
    * @return A boolean indicating whether the sql string has a Returning clause or not.
    */
   @InternalApi
-  abstract boolean checkReturningClauseInternal(String sql);
+  abstract protected boolean checkReturningClauseInternal(String sql);
 
   @InternalApi
   public boolean checkReturningClause(String sql) {

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/PostgreSQLStatementParser.java

@@ -32,6 +32,7 @@
 public class PostgreSQLStatementParser extends AbstractStatementParser {
   private static final Pattern RETURNING_PATTERN = Pattern.compile("[ ')\"]returning[ '(\"]");
   private static final Pattern AS_RETURNING_PATTERN = Pattern.compile("[ ')\"]as returning[ '(\"]");
+  private static final String RETURNING_STRING = "returning";
 
   PostgreSQLStatementParser() throws CompileException {
     super(
@@ -305,12 +306,12 @@ private boolean isReturning(String sql, int index) {
 
   @InternalApi
   @Override
-  boolean checkReturningClauseInternal(String rawSql) {
+  protected boolean checkReturningClauseInternal(String rawSql) {
     Preconditions.checkNotNull(rawSql);
     String sql = rawSql.toLowerCase();
     // Do a pre-check to check if the SQL string definitely does not have a returning clause.
     // If this check fails, do a more involved check to check for a returning clause.
-    if (!sql.contains("returning")) {
+    if (!sql.contains(RETURNING_STRING)) {
       return false;
     }
     sql = sql.replaceAll("\\s+", " ");

google-cloud-spanner/src/main/java/com/google/cloud/spanner/connection/SpannerStatementParser.java

@@ -30,7 +30,9 @@
 @InternalApi
 public class SpannerStatementParser extends AbstractStatementParser {
 
-  final Pattern THEN_RETURN_PATTERN = Pattern.compile("[ `')\"]then return[ `'(\"]");
+  private static final Pattern THEN_RETURN_PATTERN = Pattern.compile("[ `')\"]then return[ `'(\"]");
+  private static final String THEN_STRING = "then";
+  private static final String RETURN_STRING = "return";
 
   public SpannerStatementParser() throws CompileException {
     super(
@@ -280,12 +282,12 @@ private boolean isReturning(String sql, int index) {
 
   @InternalApi
   @Override
-  boolean checkReturningClauseInternal(String rawSql) {
+  protected boolean checkReturningClauseInternal(String rawSql) {
     Preconditions.checkNotNull(rawSql);
     String sql = rawSql.toLowerCase();
     // Do a pre-check to check if the SQL string definitely does not have a returning clause.
     // If this check fails, do a more involved check to check for a returning clause.
-    if (!(sql.contains("then") && sql.contains("return"))) {
+    if (!(sql.contains(THEN_STRING) && sql.contains(RETURN_STRING))) {
       return false;
     }
     sql = sql.replaceAll("\\s+", " ");