fix: make network offering update work (set the id) and read back correctly (#339)

resourceCloudStackNetworkOfferingUpdate was broken in two ways:

1. Each UpdateNetworkOffering call built its params with
   NewUpdateNetworkOfferingParams() but never set the offering id, so every
   update (name, display_text, max_connections, domain_id) failed with
   "CloudStack API error 530 ... Cannot invoke java.lang.Long.longValue()
   because id is null". Set the id on each params struct.

2. After updating, it returned resourceCloudStackInstanceRead, the instance
   read function, which looks up a VM by the network offering id and corrupts
   state. Return resourceCloudStackNetworkOfferingRead instead.

Adds an acceptance test that creates a network offering and updates its
display_text; it fails before this change and passes after. Verified against
a CloudStack advanced zone.

Signed-off-by: Ramgopal Nagaboina <ramgopal.nagaboina.dev@gmail.com>

cloudstack/resource_cloudstack_network_offering.go

diff --git a/cloudstack/resource_cloudstack_network_offering.go b/cloudstack/resource_cloudstack_network_offering.go
index f260e63..12db60b 100644
--- a/cloudstack/resource_cloudstack_network_offering.go
+++ b/cloudstack/resource_cloudstack_network_offering.go
@@ -259,6 +259,9 @@
 		// Create a new parameter struct
 		p := cs.NetworkOffering.NewUpdateNetworkOfferingParams()
 
+		// Target this network offering
+		p.SetId(d.Id())
+
 		// Set the new name
 		p.SetName(d.Get("name").(string))
 
@@ -278,6 +281,9 @@
 		// Create a new parameter struct
 		p := cs.NetworkOffering.NewUpdateNetworkOfferingParams()
 
+		// Target this network offering
+		p.SetId(d.Id())
+
 		// Set the new display text
 		p.SetDisplaytext(d.Get("display_text").(string))
 
@@ -297,6 +303,9 @@
 		// Create a new parameter struct
 		p := cs.NetworkOffering.NewUpdateNetworkOfferingParams()
 
+		// Target this network offering
+		p.SetId(d.Id())
+
 		// Set the new max connections
 		p.SetMaxconnections(d.Get("max_connections").(int))
 
@@ -316,19 +325,22 @@
 		// Create a new parameter struct
 		p := cs.NetworkOffering.NewUpdateNetworkOfferingParams()
 
+		// Target this network offering
+		p.SetId(d.Id())
+
 		// Set the new domain id
 		p.SetDomainid(d.Get("domain_id").(string))
 
-		// Update the traffic type
+		// Update the domain id
 		_, err := cs.NetworkOffering.UpdateNetworkOffering(p)
 		if err != nil {
 			return fmt.Errorf(
-				"Error updating the traffic type for network offering %s: %s", name, err)
+				"Error updating the domain id for network offering %s: %s", name, err)
 		}
 
 	}
 
-	return resourceCloudStackInstanceRead(d, meta)
+	return resourceCloudStackNetworkOfferingRead(d, meta)
 }
 
 func resourceCloudStackNetworkOfferingDelete(d *schema.ResourceData, meta interface{}) error {

cloudstack/resource_cloudstack_network_offering_test.go

diff --git a/cloudstack/resource_cloudstack_network_offering_test.go b/cloudstack/resource_cloudstack_network_offering_test.go
new file mode 100644
index 0000000..7ac7693
--- /dev/null
+++ b/cloudstack/resource_cloudstack_network_offering_test.go
@@ -0,0 +1,88 @@
+// Licensed to the Apache Software Foundation (ASF) under one
+// or more contributor license agreements.  See the NOTICE file
+// distributed with this work for additional information
+// regarding copyright ownership.  The ASF licenses this file
+// to you 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 cloudstack
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/apache/cloudstack-go/v2/cloudstack"
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/hashicorp/terraform-plugin-testing/terraform"
+)
+
+// TestAccCloudStackNetworkOffering_update creates a network offering and then updates its
+// display_text in a second step, exercising resourceCloudStackNetworkOfferingUpdate. It guards
+// against the update reading state back through the wrong resource's Read function.
+func TestAccCloudStackNetworkOffering_update(t *testing.T) {
+	name := "tf-acc-no-" + resource.UniqueId()
+
+	resource.Test(t, resource.TestCase{
+		PreCheck:     func() { testAccPreCheck(t) },
+		Providers:    testAccProviders,
+		CheckDestroy: testAccCheckCloudStackNetworkOfferingDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccNetworkOfferingUpdateConfig(name, "display text one"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("cloudstack_network_offering.foo", "name", name),
+					resource.TestCheckResourceAttr("cloudstack_network_offering.foo", "display_text", "display text one"),
+				),
+			},
+			{
+				Config: testAccNetworkOfferingUpdateConfig(name, "display text two"),
+				Check: resource.ComposeTestCheckFunc(
+					resource.TestCheckResourceAttr("cloudstack_network_offering.foo", "name", name),
+					resource.TestCheckResourceAttr("cloudstack_network_offering.foo", "display_text", "display text two"),
+				),
+			},
+		},
+	})
+}
+
+func testAccNetworkOfferingUpdateConfig(name, displayText string) string {
+	return fmt.Sprintf(`
+resource "cloudstack_network_offering" "foo" {
+  name          = "%s"
+  display_text  = "%s"
+  guest_ip_type = "Isolated"
+  traffic_type  = "Guest"
+}
+`, name, displayText)
+}
+
+func testAccCheckCloudStackNetworkOfferingDestroy(s *terraform.State) error {
+	cs := testAccProvider.Meta().(*cloudstack.CloudStackClient)
+
+	for _, rs := range s.RootModule().Resources {
+		if rs.Type != "cloudstack_network_offering" {
+			continue
+		}
+
+		if rs.Primary.ID == "" {
+			return fmt.Errorf("No network offering ID is set")
+		}
+
+		_, _, err := cs.NetworkOffering.GetNetworkOfferingByID(rs.Primary.ID)
+		if err == nil {
+			return fmt.Errorf("Network offering %s still exists", rs.Primary.ID)
+		}
+	}
+
+	return nil
+}