test(oci): add initial docker registry run setup

Author: Clockwork-Muse

api/internal/oci/pusher.go

@@ -0,0 +1,4 @@
+// Copyright 2026 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package oci

api/internal/oci/pusher_test.go

@@ -0,0 +1,90 @@
+// Copyright 2026 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package oci
+
+import (
+	"bufio"
+	"fmt"
+	"net"
+	"os/exec"
+	"strconv"
+	"strings"
+	"syscall"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func skipIfNoDocker(t *testing.T) {
+	t.Helper()
+	if _, err := exec.LookPath("docker"); err != nil {
+		t.Skip("skipping because docker binary wasn't found in PATH")
+	}
+}
+
+// Set up the registry.
+func registry(t *testing.T) (*exec.Cmd, int, error) {
+	skipIfNoDocker(t)
+
+	container_name := fmt.Sprintf("%s_%d", t.Name(), 15)
+	internal_port := 5000
+
+	registry := exec.Command("docker", "run",
+		"--rm",
+		"-p", fmt.Sprintf("0:%d", internal_port),
+		"--name", container_name,
+		"docker.io/library/registry:3.0.0",
+	)
+
+	stdout, err := registry.StderrPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := registry.Start(); err != nil {
+		t.Fatal(err)
+	}
+
+	t.Cleanup(func() { registry.Process.Signal(syscall.SIGTERM) })
+
+	scanner := bufio.NewScanner(stdout)
+	for scanner.Scan() {
+		line := scanner.Text()
+		if strings.Contains(line, fmt.Sprintf("listening on [::]:%d", internal_port)) {
+			break
+		}
+	}
+
+	if err := scanner.Err(); err != nil {
+		t.Fatal(err)
+	}
+
+	retrieve_registry_port := exec.Command("docker", "port", container_name, fmt.Sprintf("%d", internal_port))
+	out, err := retrieve_registry_port.Output()
+	if err != nil {
+		t.Fatal(err)
+	}
+	_, portString, err := net.SplitHostPort(strings.TrimSpace(string(out)))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	port, err := strconv.Atoi(portString)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	return registry, port, nil
+}
+
+func TestFnContainerTransformerWithConfig(t *testing.T) {
+	registry, port, err := registry(t)
+	require.NoError(t, err)
+	// t.Cleanup(func() {registry.})
+	require.NotNil(t, registry)
+	t.Setenv("asdfsd", "asdfadsf")
+
+	require.Equal(t, port, 5)
+
+}