Add validation scopes.

CHANGELOG.md

@@ -10,6 +10,13 @@ The format is based on [Keep a Changelog], and this project adheres to
 [keep a changelog]: https://keepachangelog.com/en/1.0.0/
 [semantic versioning]: https://semver.org/spec/v2.0.0.html
 
+## [Unreleased]
+
+### Added
+
+- Added `CommandValidationScope()`, `EventValidationScope()`, and
+  `TimeoutValidationScope()` to help when testing message validation logic.
+
 ## [0.17.2] - 2024-09-25
 
 ### Fixed

validation.go

@@ -0,0 +1,42 @@
+package testkit
+
+import (
+	"github.com/dogmatiq/dogma"
+	"github.com/dogmatiq/testkit/internal/validation"
+)
+
+// CommandValidationScope returns a [dogma.CommandValidationScope] that can be
+// used when testing command validation logic.
+func CommandValidationScope(...CommandValidationScopeOption) dogma.CommandValidationScope {
+	return validation.CommandValidationScope()
+}
+
+// EventValidationScope returns a [dogma.EventValidationScope] that can be used
+// when testing event validation logic.
+func EventValidationScope(...EventValidationScopeOption) dogma.EventValidationScope {
+	return validation.EventValidationScope()
+}
+
+// TimeoutValidationScope returns a [dogma.TimeoutValidationScope] that can be
+// used when testing timeout validation logic.
+func TimeoutValidationScope(...TimeoutValidationScopeOption) dogma.TimeoutValidationScope {
+	return validation.TimeoutValidationScope()
+}
+
+// CommandValidationScopeOption is an option that changes the behavior of a
+// [dogma.CommandValidationScope] created by calling [CommandValidationScope].
+type CommandValidationScopeOption interface {
+	reservedCommandValidationScopeOption()
+}
+
+// EventValidationScopeOption is an option that changes the behavior of a
+// [dogma.EventValidationScope] created by calling [EventValidationScope].
+type EventValidationScopeOption interface {
+	reservedEventValidationScopeOption()
+}
+
+// TimeoutValidationScopeOption is an option that changes the behavior of a
+// [dogma.TimeoutValidationScope] created by calling [TimeoutValidationScope].
+type TimeoutValidationScopeOption interface {
+	reservedTimeoutValidationScopeOption()
+}

validation_test.go

@@ -0,0 +1,21 @@
+package testkit_test
+
+import (
+	"testing"
+
+	. "github.com/dogmatiq/testkit"
+)
+
+func TestValidationScopeCreation(t *testing.T) {
+	if CommandValidationScope() == nil {
+		t.Errorf("CommandValidationScope() returned nil")
+	}
+
+	if EventValidationScope() == nil {
+		t.Errorf("EventValidationScope() returned nil")
+	}
+
+	if TimeoutValidationScope() == nil {
+		t.Errorf("TimeoutValidationScope() returned nil")
+	}
+}