feat: add With methods to customize CoreAttribute characteristics (#195)

Allow users to customize type-independent characteristics of pre-built
schema attributes without rebuilding them from scratch. This enables
use cases like making "emails" required in CoreUserSchema while reusing
the existing attribute definition.

Added methods: WithDescription, WithMutability, WithRequired,
WithReturned. All return a copy, leaving the original unmodified.

Author: q-uint

schema/core.go

@@ -291,6 +291,30 @@ func (a CoreAttribute) ValidateSingular(attribute interface{}) (interface{}, *er
 	}
 }
 
+// WithDescription returns a copy of the attribute with the given description.
+func (a CoreAttribute) WithDescription(description optional.String) CoreAttribute {
+	a.description = description
+	return a
+}
+
+// WithMutability returns a copy of the attribute with the given mutability.
+func (a CoreAttribute) WithMutability(mutability AttributeMutability) CoreAttribute {
+	a.mutability = mutability.m
+	return a
+}
+
+// WithRequired returns a copy of the attribute with the given required value.
+func (a CoreAttribute) WithRequired(required bool) CoreAttribute {
+	a.required = required
+	return a
+}
+
+// WithReturned returns a copy of the attribute with the given returned value.
+func (a CoreAttribute) WithReturned(returned AttributeReturned) CoreAttribute {
+	a.returned = returned.r
+	return a
+}
+
 func (a *CoreAttribute) getRawAttributes() map[string]interface{} {
 	attributes := map[string]interface{}{
 		"description": a.description.Value(),

schema/core_test.go

@@ -0,0 +1,75 @@
+package schema
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/elimity-com/scim/optional"
+)
+
+func ExampleCoreAttribute_WithRequired() {
+	// Customize the pre-built CoreUserSchema to make "emails" required.
+	userSchema := CoreUserSchema()
+	for i, attr := range userSchema.Attributes {
+		if attr.Name() == "emails" {
+			userSchema.Attributes[i] = attr.WithRequired(true)
+		}
+	}
+
+	emails, _ := userSchema.Attributes.ContainsAttribute("emails")
+	fmt.Println(emails.Required())
+	// Output: true
+}
+
+func TestCoreAttribute_WithDescription(t *testing.T) {
+	attr := SimpleCoreAttribute(SimpleStringParams(StringParams{
+		Name: "test",
+	}))
+	desc := optional.NewString("new description")
+	got := attr.WithDescription(desc)
+	if got.Description() != "new description" {
+		t.Errorf("WithDescription: got %q, want %q", got.Description(), "new description")
+	}
+	if attr.Description() != "" {
+		t.Error("WithDescription modified the original attribute")
+	}
+}
+
+func TestCoreAttribute_WithMutability(t *testing.T) {
+	attr := SimpleCoreAttribute(SimpleStringParams(StringParams{
+		Name: "test",
+	}))
+	got := attr.WithMutability(AttributeMutabilityImmutable())
+	if got.Mutability() != "immutable" {
+		t.Errorf("WithMutability: got %q, want %q", got.Mutability(), "immutable")
+	}
+	if attr.Mutability() != "readWrite" {
+		t.Error("WithMutability modified the original attribute")
+	}
+}
+
+func TestCoreAttribute_WithRequired(t *testing.T) {
+	attr := SimpleCoreAttribute(SimpleStringParams(StringParams{
+		Name: "test",
+	}))
+	got := attr.WithRequired(true)
+	if !got.Required() {
+		t.Error("WithRequired(true): got false, want true")
+	}
+	if attr.Required() {
+		t.Error("WithRequired modified the original attribute")
+	}
+}
+
+func TestCoreAttribute_WithReturned(t *testing.T) {
+	attr := SimpleCoreAttribute(SimpleStringParams(StringParams{
+		Name: "test",
+	}))
+	got := attr.WithReturned(AttributeReturnedNever())
+	if got.Returned() != "never" {
+		t.Errorf("WithReturned: got %q, want %q", got.Returned(), "never")
+	}
+	if attr.Returned() != "default" {
+		t.Error("WithReturned modified the original attribute")
+	}
+}