test: make t/plugin/skywalking.t stable (#5170)

t/plugin/skywalking.t

@@ -15,16 +15,6 @@
 # limitations under the License.
 #
 
-BEGIN {
-    if ($ENV{TEST_NGINX_CHECK_LEAK}) {
-        $SkipReason = "unavailable for the hup tests";
-
-    } else {
-        $ENV{TEST_NGINX_USE_HUP} = 1;
-        undef $ENV{TEST_NGINX_USE_STAP};
-    }
-}
-
 use t::APISIX 'no_plan';
 
 add_block_preprocessor(sub {
@@ -38,6 +28,10 @@ _EOC_
     $block->set_value("extra_yaml_config", $extra_yaml_config);
 
     my $extra_init_by_lua = <<_EOC_;
+    -- reduce default report interval
+    local client = require("skywalking.client")
+    client.backendTimerDelay = 0.5
+
     local sw_tracer = require("skywalking.tracer")
     local inject = function(mod, name)
         local old_f = mod[name]
@@ -129,9 +123,13 @@ GET /opentracing
 opentracing
 --- no_error_log
 [error]
---- error_log
-segments reported
---- wait: 4
+--- grep_error_log eval
+qr/skywalking run \w+/
+--- grep_error_log_out
+skywalking run start
+skywalking run finish
+skywalking run prepareForReport
+--- wait: 1
 
 
 
@@ -198,8 +196,9 @@ passed
 GET /opentracing
 --- response_body
 opentracing
---- error_log
-miss sampling, ignore
+--- grep_error_log eval
+qr/skywalking run \w+/
+--- grep_error_log_out
 --- no_error_log
 [error]
 
@@ -332,7 +331,13 @@ GET /opentracing
 opentracing
 --- no_error_log
 [error]
---- wait: 4
+--- grep_error_log eval
+qr/skywalking run \w+/
+--- grep_error_log_out
+skywalking run start
+skywalking run finish
+skywalking run prepareForReport
+--- wait: 1