Adding atMostSumOf int64 validator (#20)

int64validator/at_most_sum_of.go

@@ -0,0 +1,82 @@
+package int64validator
+
+import (
+	"context"
+	"fmt"
+	"strings"
+
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-go/tftypes"
+
+	"github.com/hashicorp/terraform-plugin-framework-validators/validatordiag"
+)
+
+var _ tfsdk.AttributeValidator = atMostSumOfValidator{}
+
+// atMostSumOfValidator validates that an integer Attribute's value is at most the sum of one
+// or more integer Attributes.
+type atMostSumOfValidator struct {
+	attributesToSumPaths []*tftypes.AttributePath
+}
+
+// Description describes the validation in plain text formatting.
+func (validator atMostSumOfValidator) Description(_ context.Context) string {
+	var attributePaths []string
+	for _, path := range validator.attributesToSumPaths {
+		attributePaths = append(attributePaths, path.String())
+	}
+
+	return fmt.Sprintf("value must be at most sum of %s", strings.Join(attributePaths, " + "))
+}
+
+// MarkdownDescription describes the validation in Markdown formatting.
+func (validator atMostSumOfValidator) MarkdownDescription(ctx context.Context) string {
+	return validator.Description(ctx)
+}
+
+// Validate performs the validation.
+func (validator atMostSumOfValidator) Validate(ctx context.Context, request tfsdk.ValidateAttributeRequest, response *tfsdk.ValidateAttributeResponse) {
+	i, ok := validateInt(ctx, request, response)
+
+	if !ok {
+		return
+	}
+
+	var sumOfAttribs int64
+
+	for _, path := range validator.attributesToSumPaths {
+		var attribToSum types.Int64
+
+		response.Diagnostics.Append(request.Config.GetAttribute(ctx, path, &attribToSum)...)
+		if response.Diagnostics.HasError() {
+			return
+		}
+
+		sumOfAttribs += attribToSum.Value
+	}
+
+	if i > sumOfAttribs {
+
+		response.Diagnostics.Append(validatordiag.AttributeValueDiagnostic(
+			request.AttributePath,
+			validator.Description(ctx),
+			fmt.Sprintf("%d", i),
+		))
+
+		return
+	}
+}
+
+// AtMostSumOf returns an AttributeValidator which ensures that any configured
+// attribute value:
+//
+//     - Is a number, which can be represented by a 64-bit integer.
+//     - Is exclusively at most the sum of the given attributes.
+//
+// Null (unconfigured) and unknown (known after apply) values are skipped.
+func AtMostSumOf(attributesToSum []*tftypes.AttributePath) tfsdk.AttributeValidator {
+	return atMostSumOfValidator{
+		attributesToSumPaths: attributesToSum,
+	}
+}

int64validator/at_most_sum_of_test.go

@@ -0,0 +1,155 @@
+package int64validator
+
+import (
+	"context"
+	"testing"
+
+	"github.com/hashicorp/terraform-plugin-framework/attr"
+	"github.com/hashicorp/terraform-plugin-framework/tfsdk"
+	"github.com/hashicorp/terraform-plugin-framework/types"
+	"github.com/hashicorp/terraform-plugin-go/tftypes"
+)
+
+func TestAtMostSumOfValidator(t *testing.T) {
+	t.Parallel()
+
+	type testCase struct {
+		val                  attr.Value
+		attributesToSumPaths []*tftypes.AttributePath
+		requestConfigRaw     map[string]attr.Value
+		expectError          bool
+	}
+	tests := map[string]testCase{
+		"not an Int64": {
+			val:         types.Bool{Value: true},
+			expectError: true,
+		},
+		"unknown Int64": {
+			val: types.Int64{Unknown: true},
+		},
+		"null Int64": {
+			val: types.Int64{Null: true},
+		},
+		"valid integer as Int64 more than sum of attributes": {
+			val: types.Int64{Value: 11},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Value: 5},
+				"two": types.Int64{Value: 5},
+			},
+			expectError: true,
+		},
+		"valid integer as Int64 equal to sum of attributes": {
+			val: types.Int64{Value: 10},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Value: 5},
+				"two": types.Int64{Value: 5},
+			},
+		},
+		"valid integer as Int64 less than sum of attributes": {
+			val: types.Int64{Value: 7},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Value: 4},
+				"two": types.Int64{Value: 4},
+			},
+		},
+		"valid integer as Int64 less than sum of attributes, when one summed attribute is null": {
+			val: types.Int64{Value: 8},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Null: true},
+				"two": types.Int64{Value: 9},
+			},
+		},
+		"valid integer as Int64 does not return error when all attributes are null": {
+			val: types.Int64{Null: true},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Null: true},
+				"two": types.Int64{Null: true},
+			},
+		},
+		"valid integer as Int64 less than sum of attributes, when one summed attribute is unknown": {
+			val: types.Int64{Value: 8},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Unknown: true},
+				"two": types.Int64{Value: 9},
+			},
+		},
+		"valid integer as Int64 does not return error when all attributes are unknown": {
+			val: types.Int64{Unknown: true},
+			attributesToSumPaths: []*tftypes.AttributePath{
+				tftypes.NewAttributePath().WithAttributeName("one"),
+				tftypes.NewAttributePath().WithAttributeName("two"),
+			},
+			requestConfigRaw: map[string]attr.Value{
+				"one": types.Int64{Unknown: true},
+				"two": types.Int64{Unknown: true},
+			},
+		},
+	}
+
+	for name, test := range tests {
+		name, test := name, test
+		t.Run(name, func(t *testing.T) {
+			reqConf := make(map[string]tftypes.Value, len(test.requestConfigRaw))
+
+			for k, v := range test.requestConfigRaw {
+				val, err := v.ToTerraformValue(context.Background())
+				if err != nil {
+					t.Fatalf("could not attr.Value at key:%s to tftypes.Value", k)
+				}
+
+				reqConf[k] = val
+			}
+
+			request := tfsdk.ValidateAttributeRequest{
+				AttributePath:   tftypes.NewAttributePath().WithAttributeName("test"),
+				AttributeConfig: test.val,
+				Config: tfsdk.Config{
+					Raw: tftypes.NewValue(tftypes.Object{}, reqConf),
+					Schema: tfsdk.Schema{
+						Attributes: map[string]tfsdk.Attribute{
+							"test": {Type: types.Int64Type},
+							"one":  {Type: types.Int64Type},
+							"two":  {Type: types.Int64Type},
+						},
+					},
+				},
+			}
+
+			response := tfsdk.ValidateAttributeResponse{}
+
+			AtMostSumOf(test.attributesToSumPaths).Validate(context.Background(), request, &response)
+
+			if !response.Diagnostics.HasError() && test.expectError {
+				t.Fatal("expected error, got no error")
+			}
+
+			if response.Diagnostics.HasError() && !test.expectError {
+				t.Fatalf("got unexpected error: %s", response.Diagnostics)
+			}
+		})
+	}
+}