test: tests para agents/registry.go

Cobertura completa del registro global de reglas:
- Register + GetRules: registro exitoso y recuperacion
- GetRules con ID inexistente: retorna nil
- Register duplicado: panic con mensaje descriptivo
- RegisteredIDs: retorna todos los IDs registrados
- resetRegistry: limpia el registro (helper para tests)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

agents/registry_test.go

@@ -0,0 +1,104 @@
+package agents
+
+import (
+	"sort"
+	"testing"
+
+	"github.com/enmanuel/agents/pkg/decision"
+)
+
+func TestRegisterAndGetRules(t *testing.T) {
+	resetRegistry()
+
+	called := false
+	fn := func() []decision.Rule {
+		called = true
+		return []decision.Rule{{Name: "test-rule"}}
+	}
+
+	Register("test-agent", fn)
+
+	got := GetRules("test-agent")
+	if got == nil {
+		t.Fatal("GetRules returned nil for registered agent")
+	}
+
+	rules := got()
+	if !called {
+		t.Error("rule factory was not called")
+	}
+	if len(rules) != 1 || rules[0].Name != "test-rule" {
+		t.Errorf("unexpected rules: %+v", rules)
+	}
+}
+
+func TestGetRulesMissing(t *testing.T) {
+	resetRegistry()
+
+	got := GetRules("nonexistent")
+	if got != nil {
+		t.Errorf("expected nil for unregistered agent, got %v", got)
+	}
+}
+
+func TestRegisterDuplicatePanics(t *testing.T) {
+	resetRegistry()
+
+	fn := func() []decision.Rule { return nil }
+	Register("dup-agent", fn)
+
+	defer func() {
+		r := recover()
+		if r == nil {
+			t.Fatal("expected panic on duplicate registration, got none")
+		}
+		msg, ok := r.(string)
+		if !ok {
+			t.Fatalf("expected string panic, got %T: %v", r, r)
+		}
+		if msg != "agents.Register: duplicate agent id: dup-agent" {
+			t.Errorf("unexpected panic message: %s", msg)
+		}
+	}()
+
+	Register("dup-agent", fn)
+}
+
+func TestRegisteredIDs(t *testing.T) {
+	resetRegistry()
+
+	Register("charlie", func() []decision.Rule { return nil })
+	Register("alpha", func() []decision.Rule { return nil })
+	Register("bravo", func() []decision.Rule { return nil })
+
+	ids := RegisteredIDs()
+	sort.Strings(ids)
+
+	expected := []string{"alpha", "bravo", "charlie"}
+	if len(ids) != len(expected) {
+		t.Fatalf("expected %d ids, got %d: %v", len(expected), len(ids), ids)
+	}
+	for i, id := range ids {
+		if id != expected[i] {
+			t.Errorf("id[%d] = %q, want %q", i, id, expected[i])
+		}
+	}
+}
+
+func TestResetRegistry(t *testing.T) {
+	resetRegistry()
+
+	Register("temp", func() []decision.Rule { return nil })
+	if GetRules("temp") == nil {
+		t.Fatal("expected registered agent")
+	}
+
+	resetRegistry()
+
+	if GetRules("temp") != nil {
+		t.Error("expected nil after reset")
+	}
+	if len(RegisteredIDs()) != 0 {
+		t.Error("expected empty registry after reset")
+	}
+}