fix show executor unit test

Signed-off-by: Harshit Gangal <[email protected]>

go/vt/vtgate/executor_test.go

@@ -437,7 +437,7 @@ func TestExecutorShowColumns(t *testing.T) {
 
 func TestExecutorShow(t *testing.T) {
 	executor, _, _, sbclookup := createLegacyExecutorEnv()
-	session := NewSafeSession(&vtgatepb.Session{TargetString: "@master"})
+	session := NewSafeSession(&vtgatepb.Session{TargetString: "TestExecutor"})
 
 	for _, query := range []string{"show vitess_keyspaces", "show keyspaces"} {
 		qr, err := executor.Execute(ctx, "TestExecute", session, query, nil)
@@ -459,6 +459,8 @@ func TestExecutorShow(t *testing.T) {
 	_, err = executor.Execute(ctx, "TestExecute", session, "show collation where `Charset` = 'utf8' and `Collation` = 'utf8_bin'", nil)
 	require.NoError(t, err)
 
+	_, err = executor.Execute(ctx, "TestExecute", session, "use @master", nil)
+	require.NoError(t, err)
 	_, err = executor.Execute(ctx, "TestExecute", session, "show tables", nil)
 	assert.EqualError(t, err, "keyspace not specified", "'show tables' should fail without a keyspace")
 	assert.Empty(t, sbclookup.Queries, "sbclookup unexpectedly has queries already")