add slowstart code

test/test_images/slowstart/main.go

@@ -0,0 +1,37 @@
+/*
+Copyright 2023 The Knative Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"log"
+	"time"
+)
+
+func main() {
+	sleep := flag.Int("sleep", 0, "Time to sleep in seconds")
+	flag.Parse()
+
+	duration, err := time.ParseDuration(fmt.Sprintf("%ds", *sleep))
+	if err != nil {
+		log.Fatalf("Could not parse duration: %d, err: %v", *sleep, err)
+	}
+	time.Sleep(duration)
+
+	log.Printf("Sleept for: %ds", *sleep)
+}

test/test_images/slowstart/service.yaml

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+# Copyright 2023 The Knative Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+apiVersion: serving.knative.dev/v1
+kind: Service
+metadata:
+  name: slow-start
+  namespace: default
+spec:
+  template:
+    spec:
+      containers:
+      - image: ko://knative.dev/serving/test/test_images/slowstart