Clarify docs and resolve tf warnings

docs/usage.md

@@ -128,8 +128,8 @@ module "my_backup" {
 
 | Name | Description | Required | Default |
 |------|-------------|-----------|---------|
-| `resource_group_name` | The name of the resource group that is created to contain the vault - this cannot be an existing resource group. | Yes | n/a |
-| `resource_group_location` | The location of the resource group that is created to contain the vault. | No | `uksouth` |
+| `resource_group_name` | The name of the resource group that is created to contain the vault - the resource group will be created if `create_resource_group` = true, and must be an existing resource group if `create_resource_group` = false. | Yes | n/a |
+| `resource_group_location` | The location of the resource group. | No | `uksouth` |
 | `create_resource_group` | States whether a resource group should be created. Setting this to `false` means the vault will be deployed into an externally managed resource group, the name of which is defined in `resource_group_name`. | No | `true` |
 | `backup_vault_name` | The name of the backup vault. The value supplied will be automatically prefixed with `rg-nhsbackup-`. If more than one az-backup module is created, this value must be unique across them. | Yes | n/a |
 | `backup_vault_redundancy` | The redundancy of the vault, e.g. `GeoRedundant`. [See the following link for the possible values.](https://registry.terraform.io/providers/hashicorp/azurerm/latest/docs/resources/data_protection_backup_vault#redundancy) | No | `LocallyRedundant` |

infrastructure/backup_vault.tf

@@ -39,10 +39,10 @@ resource "azurerm_monitor_diagnostic_setting" "backup_vault" {
     }
   }
 
-  dynamic "metric" {
+  dynamic "enabled_metric" {
     for_each = toset(local.backup_vault_diagnostics_metric_categories)
     content {
-      category = metric.key
+      category = enabled_metric.key
     }
   }
 }

infrastructure/main.tf

@@ -7,6 +7,4 @@ terraform {
       version = ">= 4.18.0, < 5.0"
     }
   }
-
-  backend "azurerm" {}
 }

tests/integration-tests/backup_vault.tftest.hcl

@@ -71,7 +71,7 @@ run "create_backup_vault" {
     ])
     error_message = "Tags not as expected."
   }
-  
+
   assert {
     condition     = azurerm_data_protection_backup_vault.backup_vault.immutability == var.backup_vault_immutability
     error_message = "Backup vault immutability not as expected."
@@ -119,12 +119,12 @@ run "configure_vault_diagnostics_when_enabled" {
   }
 
   assert {
-    condition     = length(azurerm_monitor_diagnostic_setting.backup_vault[0].metric) == length(local.backup_vault_diagnostics_metric_categories)
+    condition     = length(azurerm_monitor_diagnostic_setting.backup_vault[0].enabled_metric) == length(local.backup_vault_diagnostics_metric_categories)
     error_message = "Backup vault diagnostic setting metrics not as expected."
   }
 
   assert {
-    condition     = alltrue([for metric in azurerm_monitor_diagnostic_setting.backup_vault[0].metric : contains(local.backup_vault_diagnostics_metric_categories, metric.category)])
+    condition     = alltrue([for metric in azurerm_monitor_diagnostic_setting.backup_vault[0].enabled_metric : contains(local.backup_vault_diagnostics_metric_categories, metric.category)])
     error_message = "Backup vault diagnostic setting metrics not as expected."
   }
 }

tests/integration-tests/main.tf

@@ -2,7 +2,7 @@ terraform {
   required_providers {
     azurerm = {
       source  = "hashicorp/azurerm"
-      version = "4.18.0"
+      version = ">= 4.18.0, < 5.0"
     }
   }
 }