chore: clean up some test warnings

conn_with_mockserver_test.go

@@ -273,7 +273,7 @@ func TestSetIsolationLevel(t *testing.T) {
 		if g, w := level, sql.LevelSnapshot; g != w {
 			t.Fatalf("isolation level mismatch\n Got: %v\nWant: %v", g, w)
 		}
-		conn.Close()
+		_ = conn.Close()
 	}
 }
 
@@ -335,7 +335,7 @@ func TestDDLUsingQueryContextInReadOnlyTx(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer tx.Rollback()
+	defer func() { _ = tx.Rollback() }()
 
 	// DDL statements should not use the query context in a read-only transaction.
 	_, err = tx.QueryContext(ctx, "CREATE TABLE Foo (Bar STRING(100))")
@@ -358,7 +358,7 @@ func TestDDLUsingQueryContextInReadWriteTransaction(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer tx.Rollback()
+	defer func() { _ = tx.Rollback() }()
 
 	// DDL statements should not use the query context in a read-write transaction.
 	_, err = tx.QueryContext(ctx, "CREATE TABLE Foo (Bar STRING(100))")

connection_leak_test.go

@@ -75,7 +75,7 @@ func simpleQuery(ctx context.Context, t *testing.T, db *sql.DB) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer rows.Close()
+	defer silentClose(rows)
 
 	for want := int64(1); rows.Next(); want++ {
 		_, err := rows.Columns()
@@ -202,7 +202,7 @@ func readOnlyTxWithStaleness(ctx context.Context, t *testing.T, db *sql.DB) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer conn.Close()
+	defer silentClose(conn)
 	if _, err := conn.ExecContext(ctx, "SET READ_ONLY_STALENESS = 'EXACT_STALENESS 10s'"); err != nil {
 		t.Fatalf("Set read-only staleness: %v", err)
 	}
@@ -233,7 +233,7 @@ func simpleReadWriteTx(ctx context.Context, t *testing.T, db *sql.DB) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	defer conn.Close()
+	defer silentClose(conn)
 	if _, err := conn.ExecContext(ctx, "set max_commit_delay='10ms'"); err != nil {
 		t.Fatal(err)
 	}

driver_test.go

@@ -20,6 +20,7 @@ import (
 	"database/sql/driver"
 	"encoding/json"
 	"fmt"
+	"io"
 	"net"
 	"reflect"
 	"testing"
@@ -34,7 +35,12 @@ import (
 	"google.golang.org/grpc/codes"
 )
 
+func silentClose(c io.Closer) {
+	_ = c.Close()
+}
+
 func TestExtractDnsParts(t *testing.T) {
+	//goland:noinspection GoDeprecation
 	tests := []struct {
 		input               string
 		wantConnectorConfig ConnectorConfig
@@ -470,7 +476,7 @@ func ExampleCreateConnector() {
 	db := sql.OpenDB(c)
 	// Use the database ...
 
-	defer db.Close()
+	defer silentClose(db)
 }
 
 func TestConnection_Reset(t *testing.T) {