Make IPv6 acceptance tests conditionally skip based on environment

IPv6 acceptance tests are now conditionally skipped instead of being
unconditionally skipped. The tests will:

1. Skip on localhost/127.0.0.1 (assumed to be simulator) by default
2. Run on other API URLs (assumed to be real CloudStack)
3. Can be force-enabled via CLOUDSTACK_ENABLE_IPV6_TESTS=true env var

This allows the tests to run on real CloudStack environments with IPv6
support while still skipping on the simulator where IPv6 is not supported
for isolated networks.

Added testAccPreCheckIPv6Support() helper function that checks:
- Standard testAccPreCheck() requirements
- CLOUDSTACK_ENABLE_IPV6_TESTS environment variable for override
- API URL to detect simulator (localhost/127.0.0.1)

Author: bhouse-nexthop

cloudstack/resource_cloudstack_network_test.go

@@ -17,17 +17,20 @@
 // under the License.
 //
 
-// NOTE: IPv6 acceptance tests (TestAccCloudStackNetwork_ipv6*) are currently
+// NOTE: IPv6 acceptance tests (TestAccCloudStackNetwork_ipv6*) are conditionally
 // skipped when running against the CloudStack simulator because the simulator
 // only supports IPv6 with advanced shared network offerings. These tests will
-// work correctly against a real CloudStack environment with proper IPv6 support.
+// run on real CloudStack environments with proper IPv6 support. Set the environment
+// variable CLOUDSTACK_ENABLE_IPV6_TESTS=true to force-enable IPv6 tests.
 // Unit tests for the IPv6 CIDR parsing logic are available in
 // resource_cloudstack_network_unit_test.go and do not require a CloudStack instance.
 
 package cloudstack
 
 import (
 	"fmt"
+	"os"
+	"strings"
 	"testing"
 
 	"github.com/apache/cloudstack-go/v2/cloudstack"
@@ -172,12 +175,29 @@ func TestAccCloudStackNetwork_importProject(t *testing.T) {
 	})
 }
 
+// testAccPreCheckIPv6Support checks if IPv6 tests should run.
+// IPv6 tests are skipped on the CloudStack simulator unless explicitly enabled
+// via the CLOUDSTACK_ENABLE_IPV6_TESTS environment variable.
+func testAccPreCheckIPv6Support(t *testing.T) {
+	testAccPreCheck(t)
+
+	// Allow explicit override to enable IPv6 tests
+	if os.Getenv("CLOUDSTACK_ENABLE_IPV6_TESTS") == "true" {
+		return
+	}
+
+	// Try to detect if we're running on the simulator by checking the API URL
+	apiURL := os.Getenv("CLOUDSTACK_API_URL")
+	if strings.Contains(apiURL, "localhost") || strings.Contains(apiURL, "127.0.0.1") {
+		t.Skip("Skipping IPv6 test: CloudStack simulator does not support IPv6 for isolated networks. Set CLOUDSTACK_ENABLE_IPV6_TESTS=true to force-enable.")
+	}
+}
+
 func TestAccCloudStackNetwork_ipv6(t *testing.T) {
-	t.Skip("Skipping IPv6 test: CloudStack simulator only supports IPv6 with advanced shared networks")
 	var network cloudstack.Network
 
 	resource.Test(t, resource.TestCase{
-		PreCheck:     func() { testAccPreCheck(t) },
+		PreCheck:     func() { testAccPreCheckIPv6Support(t) },
 		Providers:    testAccProviders,
 		CheckDestroy: testAccCheckCloudStackNetworkDestroy,
 		Steps: []resource.TestStep{
@@ -196,11 +216,10 @@ func TestAccCloudStackNetwork_ipv6(t *testing.T) {
 }
 
 func TestAccCloudStackNetwork_ipv6_vpc(t *testing.T) {
-	t.Skip("Skipping IPv6 test: CloudStack simulator only supports IPv6 with advanced shared networks")
 	var network cloudstack.Network
 
 	resource.Test(t, resource.TestCase{
-		PreCheck:     func() { testAccPreCheck(t) },
+		PreCheck:     func() { testAccPreCheckIPv6Support(t) },
 		Providers:    testAccProviders,
 		CheckDestroy: testAccCheckCloudStackNetworkDestroy,
 		Steps: []resource.TestStep{
@@ -218,11 +237,10 @@ func TestAccCloudStackNetwork_ipv6_vpc(t *testing.T) {
 }
 
 func TestAccCloudStackNetwork_ipv6_custom_gateway(t *testing.T) {
-	t.Skip("Skipping IPv6 test: CloudStack simulator only supports IPv6 with advanced shared networks")
 	var network cloudstack.Network
 
 	resource.Test(t, resource.TestCase{
-		PreCheck:     func() { testAccPreCheck(t) },
+		PreCheck:     func() { testAccPreCheckIPv6Support(t) },
 		Providers:    testAccProviders,
 		CheckDestroy: testAccCheckCloudStackNetworkDestroy,
 		Steps: []resource.TestStep{