Merge pull request #59 from mmourick/feat/add-string-assert-functions

feat: add `empty` and `not_empty` functions

docs/functions/empty.md

@@ -0,0 +1,54 @@
+---
+page_title: "empty function - terraform-provider-assert"
+subcategory: "String Functions"
+description: |-
+  Checks wether a given string is empty
+---
+
+# function: empty
+
+
+
+## Terraform Test Example
+
+```terraform
+run "check_cloudwatch_log_subscription_match_all" {
+
+  command = plan
+
+  assert {
+    condition     = provider::assert::empty(aws_cloudwatch_log_subscription_filter.example.filter_pattern)
+    error_message = "CloudWatch log subscription filter pattern must be empty, as it is a match all."
+  }
+}
+```
+
+## Variable Validation Example
+
+```terraform
+variable "example" {
+  type = string
+
+  validation {
+    condition     = provider::assert::empty(var.example)
+    error_message = "Variable 'example' must be empty."
+  }
+}
+```
+
+## Signature
+
+<!-- signature generated by tfplugindocs -->
+```text
+empty(s string) bool
+```
+
+## Arguments
+
+<!-- arguments generated by tfplugindocs -->
+1. `s` (String) The string to check
+
+
+## Return Type
+
+The return type of `empty` is a boolean.

docs/functions/not_empty.md

@@ -0,0 +1,54 @@
+---
+page_title: "not_empty function - terraform-provider-assert"
+subcategory: "String Functions"
+description: |-
+  Checks wether a given string is not empty
+---
+
+# function: not_empty
+
+
+
+## Terraform Test Example
+
+```terraform
+run "check_security_group_description" {
+
+  command = plan
+
+  assert {
+    condition     = provider::assert::not_empty(aws_security_group.example.description)
+    error_message = "Security group description must not be empty."
+  }
+}
+```
+
+## Variable Validation Example
+
+```terraform
+variable "example" {
+  type = string
+
+  validation {
+    condition     = provider::assert::not_empty(var.example)
+    error_message = "Variable 'example' must not be empty."
+  }
+}
+```
+
+## Signature
+
+<!-- signature generated by tfplugindocs -->
+```text
+not_empty(s string) bool
+```
+
+## Arguments
+
+<!-- arguments generated by tfplugindocs -->
+1. `s` (String) The string to check
+
+
+## Return Type
+
+The return type of `not_empty` is a boolean.

examples/functions/empty/function.tf

@@ -0,0 +1,9 @@
+run "check_cloudwatch_log_subscription_match_all" {
+
+  command = plan
+
+  assert {
+    condition     = provider::assert::empty(aws_cloudwatch_log_subscription_filter.example.filter_pattern)
+    error_message = "CloudWatch log subscription filter pattern must be empty, as it is a match all."
+  }
+}

examples/functions/empty/variable.tf

@@ -0,0 +1,8 @@
+variable "example" {
+  type = string
+
+  validation {
+    condition     = provider::assert::empty(var.example)
+    error_message = "Variable 'example' must be empty."
+  }
+}

examples/functions/not_empty/function.tf

@@ -0,0 +1,9 @@
+run "check_security_group_description" {
+
+  command = plan
+
+  assert {
+    condition     = provider::assert::not_empty(aws_security_group.example.description)
+    error_message = "Security group description must not be empty."
+  }
+}

examples/functions/not_empty/variable.tf

@@ -0,0 +1,8 @@
+variable "example" {
+  type = string
+
+  validation {
+    condition     = provider::assert::not_empty(var.example)
+    error_message = "Variable 'example' must not be empty."
+  }
+}

internal/provider/empty_function.go

@@ -0,0 +1,53 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"context"
+
+	"github.com/hashicorp/terraform-plugin-framework/function"
+)
+
+var (
+	_ function.Function = EmptyFunction{}
+)
+
+func NewEmptyFunction() function.Function {
+	return EmptyFunction{}
+}
+
+type EmptyFunction struct{}
+
+func (r EmptyFunction) Metadata(_ context.Context, req function.MetadataRequest, resp *function.MetadataResponse) {
+	resp.Name = "empty"
+}
+
+func (r EmptyFunction) Definition(_ context.Context, _ function.DefinitionRequest, resp *function.DefinitionResponse) {
+	resp.Definition = function.Definition{
+		Summary: "Checks wether a given string is empty",
+		Parameters: []function.Parameter{
+			function.StringParameter{
+				AllowNullValue:     false,
+				AllowUnknownValues: false,
+				Description:        "The string to check",
+				Name:               "s",
+			},
+		},
+		Return: function.BoolReturn{},
+	}
+}
+
+func (r EmptyFunction) Run(ctx context.Context, req function.RunRequest, resp *function.RunResponse) {
+	var argument string
+
+	resp.Error = function.ConcatFuncErrors(req.Arguments.Get(ctx, &argument))
+	if resp.Error != nil {
+		return
+	}
+	resp.Error = function.ConcatFuncErrors(resp.Result.Set(ctx, isEmpty(argument)))
+}
+
+func isEmpty(argument string) bool {
+	return len(argument) == 0
+}

internal/provider/empty_function_test.go

@@ -0,0 +1,171 @@
+// Copyright (c) HashiCorp, Inc.
+// SPDX-License-Identifier: MPL-2.0
+
+package provider
+
+import (
+	"regexp"
+	"testing"
+
+	"github.com/hashicorp/go-version"
+	"github.com/hashicorp/terraform-plugin-testing/helper/resource"
+	"github.com/hashicorp/terraform-plugin-testing/tfversion"
+)
+
+func TestEmptyFunction_stringEmpty(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+output "test" {
+  value = provider::assert::empty("")
+}
+				`,
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckOutput("test", "true"),
+				),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_stringNotEmpty(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+output "test" {
+  value = provider::assert::empty("notempty")
+}
+				`,
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckOutput("test", "false"),
+				),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_whitespaceString(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+output "test" {
+  value = provider::assert::empty("   ")
+}
+				`,
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckOutput("test", "false"),
+				),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_null(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+locals {
+  example = null
+}
+
+output "test" {
+  value = provider::assert::empty(local.example)
+}
+				`,
+				ExpectError: regexp.MustCompile(`Invalid value for "string" parameter: argument must not be null`),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_listError(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+output "test" {
+  value = provider::assert::empty([])
+}
+				`,
+				ExpectError: regexp.MustCompile(`Invalid value for "string" parameter: string required`),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_trimmedWhitespaceTrue(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+locals {
+  example = ""
+}
+
+output "test" {
+  value = provider::assert::empty(trimspace(local.example))
+}
+				`,
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckOutput("test", "true"),
+				),
+			},
+		},
+	})
+}
+
+func TestEmptyFunction_specialCharacters(t *testing.T) {
+	t.Parallel()
+	resource.UnitTest(t, resource.TestCase{
+		TerraformVersionChecks: []tfversion.TerraformVersionCheck{
+			tfversion.SkipBelow(version.Must(version.NewVersion(MinimalRequiredTerraformVersion))),
+		},
+		ProtoV6ProviderFactories: testAccProtoV6ProviderFactories,
+		Steps: []resource.TestStep{
+			{
+				Config: `
+output "test" {
+  value = provider::assert::empty("!@#$%^&*()")
+}
+				`,
+				Check: resource.ComposeAggregateTestCheckFunc(
+					resource.TestCheckOutput("test", "false"),
+				),
+			},
+		},
+	})
+}