Add health check test image. (#918)

tests/images/healthcheck/is-healthy.go

@@ -0,0 +1,35 @@
+/*
+  Copyright (c) Ansible Project
+  GNU General Public License v3.0+ (see LICENSES/GPL-3.0-or-later.txt or https://www.gnu.org/licenses/gpl-3.0.txt)
+  SPDX-License-Identifier: GPL-3.0-or-later
+*/
+
+package main
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+)
+
+func main() {
+	data, err := os.ReadFile("health.txt")
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "Error while reading health status: %s\n", err)
+		os.Exit(1)
+	}
+	if bytes.Equal(data, []byte("healthy")) {
+		fmt.Fprintf(os.Stdout, "Healthy.\n")
+		os.Exit(0)
+	}
+	if bytes.Equal(data, []byte("unhealthy")) {
+		fmt.Fprintf(os.Stdout, "Unhealthy!\n")
+		os.Exit(1)
+	}
+	if bytes.Equal(data, []byte("starting")) {
+		fmt.Fprintf(os.Stdout, "Starting...\n")
+		os.Exit(1)
+	}
+	fmt.Fprintf(os.Stderr, "Unknown health status: %s\n", data)
+	os.Exit(1)
+}