Acceptance testing custom function not finding function in provider

[JacobPotter]

terraform-plugin-testing version

github.com/hashicorp/terraform-plugin-testing v1.11.0

Relevant provider source code

Custom provider function

package provider

import (
	"cmp"
	"context"
	"github.com/Dynatrace/terraform-provider-zendesk/internal/models"
	"github.com/hashicorp/terraform-plugin-framework/function"
	"github.com/hashicorp/terraform-plugin-framework/types"
	"slices"
)

var _ function.Function = &SortCustomFieldOptions{}

type SortCustomFieldOptions struct{}

func NewSortCustomFieldOptions() function.Function {
	return &SortCustomFieldOptions{}
}

func (s *SortCustomFieldOptions) Metadata(ctx context.Context, request function.MetadataRequest, response *function.MetadataResponse) {
	response.Name = "sort_custom_field_options"
}

func (s *SortCustomFieldOptions) Definition(ctx context.Context, request function.DefinitionRequest, response *function.DefinitionResponse) {
	response.Definition = function.Definition{
		Summary:     "Sort custom field options",
		Description: "Sort custom field options by display name",
		Parameters: []function.Parameter{
			function.ListParameter{
				Name:        "custom_field_options",
				Description: "Custom field options to sort",
				ElementType: types.ObjectType{AttrTypes: models.CustomFieldOptionResourceModel{}.AttributeTypes()},
			},
		},
		Return: function.ListReturn{ElementType: types.ObjectType{AttrTypes: models.CustomFieldOptionResourceModel{}.AttributeTypes()}},
	}
}

func (s *SortCustomFieldOptions) Run(ctx context.Context, request function.RunRequest, response *function.RunResponse) {
	var customFieldOptionsList types.List

	response.Error = function.ConcatFuncErrors(response.Error, request.Arguments.Get(ctx, &customFieldOptionsList))

	var customFieldOptions []models.CustomFieldOptionResourceModel

	diags := customFieldOptionsList.ElementsAs(ctx, &customFieldOptions, true)

	if diags.HasError() {
		response.Error = function.ConcatFuncErrors(response.Error, function.NewFuncError("Error converting list to custom field options"))
		return
	}

	slices.SortFunc(customFieldOptions, func(a, b models.CustomFieldOptionResourceModel) int {
		return cmp.Compare(a.Name.ValueString(), b.Name.ValueString())
	})

	customFieldOptionsList, diags = types.ListValueFrom(ctx, types.ObjectType{AttrTypes: models.CustomFieldOptionResourceModel{}.AttributeTypes()}, customFieldOptions)

	if diags.HasError() {
		response.Error = function.ConcatFuncErrors(response.Error, function.NewFuncError("Error converting custom field options to list"))
		return
	}

	response.Error = function.ConcatFuncErrors(response.Error, response.Result.Set(ctx, customFieldOptionsList))
}

Function in Provider def

func (p *ZendeskProvider) Functions(ctx context.Context) []func() function.Function {
	return []func() function.Function{
		NewSortCustomFieldOptions,
	}
}

func TestSortCustomFieldOptionsValid(t *testing.T) {
	t.Parallel()

	resource.UnitTest(t, resource.TestCase{
		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
		Steps: []resource.TestStep{
			{
				ConfigFile: config.TestNameFile("main.tf"),
			},
		},
	})
}

Terraform Configuration Files

locals {
  cfos=[
	{name:"T",value:"T"},
	{name:"H",value:"H"},
	{name:"D",value:"D"},
	{name:"L",value:"L"}
  ]
}

output "test" {
  value = provider::zendesk::sort_custom_field_options(local.cfos)
}

Expected Behavior

Actual Behavior

Steps to Reproduce

References

[austinvalle]

Hey there @JacobPotter 👋🏻 , thanks for reporting the issue and sorry you're running into trouble here.

I'm assuming the error you're seeing is something like:

        Error: Unknown provider function
        
          on main.tf line 11, in output "test":
          10:   value = provider::zendesk::sort_custom_field_options(local.cfos)
        
        There is no function named "provider::zendesk::sort_custom_field_options". Ensure that
        provider name "zendesk" is declared in this module's required_providers block,
        and that this provider offers a function named "sort_custom_field_options".

---

If so, I think all you need to do is add a required_providers block to your main.tf test file:

terraform {
  required_providers {
    zendesk = {
      # https://developer.hashicorp.com/terraform/language/providers/requirements#source-addresses
      source = "<source address>" 
    }
  }
}

locals {
  cfos=[
	{name:"T",value:"T"},
	{name:"H",value:"H"},
	{name:"D",value:"D"},
	{name:"L",value:"L"}
  ]
}

output "test" {
  value = provider::zendesk::sort_custom_field_options(local.cfos)
}

---

When using ConfigFile or ConfigDirectory, we treat them as "ready-to-run" configuration, which is different from the static string Config field, where we will attempt to inject the required_providers block if one is not provided.

For example, the time provider uses the Config field, so it doesn't include the required_providers block: https://github.com/hashicorp/terraform-provider-time/blob/e5a617df3d678be87d3ade238b65a9808336b4b7/internal/provider/function_rfc3339_parse_test.go#L24-L28

But if we wanted to run that same test with ConfigFile, we would need to create a .tf file with:

terraform {
  required_providers {
    time = {
      source = "hashicorp/time"
    }
  }
}

output "test" {
  value = provider::time::rfc3339_parse("2023-07-25T23:43:16Z")
}

---

Hopefully that helps!