diff --git a/blackboard/bb_param/bb_param.cpp b/blackboard/bb_param/bb_param.cpp
index 2d550c2..88ad5e7 100644
--- a/blackboard/bb_param/bb_param.cpp
+++ b/blackboard/bb_param/bb_param.cpp
@@ -79,6 +79,9 @@ Variant BBParam::get_value(Object *p_agent, const Ref<Blackboard> &p_blackboard,
 	ERR_FAIL_COND_V(!p_blackboard.is_valid(), p_default);
 
 	if (value_source == SAVED_VALUE) {
+		if (saved_value == Variant()) {
+			_assign_default_value();
+		}
 		return saved_value;
 	} else {
 		ERR_FAIL_COND_V_MSG(!p_blackboard->has_var(variable), p_default, vformat("BBParam: Blackboard variable \"%s\" doesn't exist.", variable));
@@ -114,6 +117,4 @@ void BBParam::_bind_methods() {
 
 BBParam::BBParam() {
 	value_source = SAVED_VALUE;
-
-	_assign_default_value();
 }
diff --git a/tests/test_bb_param.h b/tests/test_bb_param.h
index 1618430..8243e6a 100644
--- a/tests/test_bb_param.h
+++ b/tests/test_bb_param.h
@@ -17,8 +17,14 @@
 #include "core/object/ref_counted.h"
 #include "core/string/node_path.h"
 #include "core/variant/variant.h"
+#include "modules/limboai/blackboard/bb_param/bb_bool.h"
+#include "modules/limboai/blackboard/bb_param/bb_float.h"
+#include "modules/limboai/blackboard/bb_param/bb_int.h"
 #include "modules/limboai/blackboard/bb_param/bb_node.h"
 #include "modules/limboai/blackboard/bb_param/bb_param.h"
+#include "modules/limboai/blackboard/bb_param/bb_string.h"
+#include "modules/limboai/blackboard/bb_param/bb_variant.h"
+#include "modules/limboai/blackboard/bb_param/bb_vector2.h"
 #include "modules/limboai/blackboard/blackboard.h"
 #include "modules/limboai/bt/tasks/bt_task.h"
 #include "tests/test_macros.h"
@@ -122,6 +128,68 @@ TEST_CASE("[Modules][LimboAI] BBNode") {
 	memdelete(dummy);
 }
 
+TEST_CASE("[Modules][LimboAI] BBParam default values") {
+	Node *dummy = memnew(Node);
+	Ref<Blackboard> bb = memnew(Blackboard);
+
+	SUBCASE("Test default value for BBBool") {
+		Ref<BBBool> param = memnew(BBBool);
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(false));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+	SUBCASE("Test default value for BBInt") {
+		Ref<BBInt> param = memnew(BBInt);
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(0));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+	SUBCASE("Test default value for BBFloat") {
+		Ref<BBFloat> param = memnew(BBFloat);
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(0.0));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+	SUBCASE("Test default value for BBString") {
+		Ref<BBString> param = memnew(BBString);
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(""));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+	SUBCASE("Test default value for BBVector2") {
+		Ref<BBVector2> param = memnew(BBVector2);
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(Vector2()));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+	SUBCASE("Test default value for BBVariant") {
+		Ref<BBVariant> param = memnew(BBVariant);
+		CHECK_EQ(param->get_value(dummy, bb), Variant());
+		param->set_value_source(BBParam::SAVED_VALUE);
+		CHECK_EQ(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::BOOL);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(false));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::INT);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(0));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::FLOAT);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(0.0));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::STRING);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(""));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::VECTOR2);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(Vector2()));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+		param->set_type(Variant::NODE_PATH);
+		CHECK_EQ(param->get_value(dummy, bb), Variant(NodePath()));
+		CHECK_NE(param->get_value(dummy, bb), Variant());
+	}
+
+	memdelete(dummy);
+}
+
 } //namespace TestBBParam
 
 #endif // TEST_BB_PARAM_H
diff --git a/tests/test_hsm.h b/tests/test_hsm.h
index 184f086..533f279 100644
--- a/tests/test_hsm.h
+++ b/tests/test_hsm.h
@@ -24,6 +24,12 @@
 
 namespace TestHSM {
 
+inline void wire_callbacks(LimboState *p_state, Ref<CallbackCounter> p_entries_counter, Ref<CallbackCounter> p_updates_counter, Ref<CallbackCounter> p_exits_counter) {
+	p_state->call_on_enter(callable_mp(p_entries_counter.ptr(), &CallbackCounter::callback));
+	p_state->call_on_update(callable_mp(p_updates_counter.ptr(), &CallbackCounter::callback_delta));
+	p_state->call_on_exit(callable_mp(p_exits_counter.ptr(), &CallbackCounter::callback));
+}
+
 class TestGuard : public RefCounted {
 	GDCLASS(TestGuard, RefCounted);
 
@@ -42,22 +48,38 @@ TEST_CASE("[Modules][LimboAI] HSM") {
 	Ref<CallbackCounter> beta_entries = memnew(CallbackCounter);
 	Ref<CallbackCounter> beta_exits = memnew(CallbackCounter);
 	Ref<CallbackCounter> beta_updates = memnew(CallbackCounter);
+	Ref<CallbackCounter> nested_entries = memnew(CallbackCounter);
+	Ref<CallbackCounter> nested_exits = memnew(CallbackCounter);
+	Ref<CallbackCounter> nested_updates = memnew(CallbackCounter);
+	Ref<CallbackCounter> gamma_entries = memnew(CallbackCounter);
+	Ref<CallbackCounter> gamma_exits = memnew(CallbackCounter);
+	Ref<CallbackCounter> gamma_updates = memnew(CallbackCounter);
+	Ref<CallbackCounter> delta_entries = memnew(CallbackCounter);
+	Ref<CallbackCounter> delta_exits = memnew(CallbackCounter);
+	Ref<CallbackCounter> delta_updates = memnew(CallbackCounter);
 
 	LimboState *state_alpha = memnew(LimboState);
-	state_alpha->call_on_enter(callable_mp(alpha_entries.ptr(), &CallbackCounter::callback));
-	state_alpha->call_on_update(callable_mp(alpha_updates.ptr(), &CallbackCounter::callback_delta));
-	state_alpha->call_on_exit(callable_mp(alpha_exits.ptr(), &CallbackCounter::callback));
-
+	wire_callbacks(state_alpha, alpha_entries, alpha_updates, alpha_exits);
 	LimboState *state_beta = memnew(LimboState);
-	state_beta->call_on_enter(callable_mp(beta_entries.ptr(), &CallbackCounter::callback));
-	state_beta->call_on_update(callable_mp(beta_updates.ptr(), &CallbackCounter::callback_delta));
-	state_beta->call_on_exit(callable_mp(beta_exits.ptr(), &CallbackCounter::callback));
+	wire_callbacks(state_beta, beta_entries, beta_updates, beta_exits);
+	LimboHSM *nested_hsm = memnew(LimboHSM);
+	wire_callbacks(nested_hsm, nested_entries, nested_updates, nested_exits);
+	LimboState *state_gamma = memnew(LimboState);
+	wire_callbacks(state_gamma, gamma_entries, gamma_updates, gamma_exits);
+	LimboState *state_delta = memnew(LimboState);
+	wire_callbacks(state_delta, delta_entries, delta_updates, delta_exits);
 
 	hsm->add_child(state_alpha);
 	hsm->add_child(state_beta);
+	hsm->add_child(nested_hsm);
+	nested_hsm->add_child(state_gamma);
+	nested_hsm->add_child(state_delta);
 
 	hsm->add_transition(state_alpha, state_beta, "event_one");
 	hsm->add_transition(state_beta, state_alpha, "event_two");
+	hsm->add_transition(hsm->anystate(), nested_hsm, "goto_nested");
+	nested_hsm->add_transition(state_gamma, state_delta, "goto_delta");
+	nested_hsm->add_transition(state_delta, state_gamma, "goto_gamma");
 
 	hsm->set_initial_state(state_alpha);
 	Ref<Blackboard> parent_scope = memnew(Blackboard);
@@ -179,6 +201,57 @@ TEST_CASE("[Modules][LimboAI] HSM") {
 		CHECK(state_beta->get_blackboard()->get_parent() == parent_scope);
 		CHECK(state_alpha->get_blackboard()->get_var("parent_var", Variant()) == Variant(100));
 	}
+	SUBCASE("Test flow with a nested HSM, and test dispatch() from nested states") {
+		state_gamma->dispatch("goto_nested");
+		CHECK(hsm->get_leaf_state() == state_gamma);
+		CHECK(nested_entries->num_callbacks == 1);
+		CHECK(nested_updates->num_callbacks == 0);
+		CHECK(nested_exits->num_callbacks == 0);
+		CHECK(gamma_entries->num_callbacks == 1);
+		CHECK(gamma_updates->num_callbacks == 0);
+		CHECK(gamma_exits->num_callbacks == 0);
+
+		hsm->update(0.01666);
+		CHECK(nested_entries->num_callbacks == 1);
+		CHECK(nested_updates->num_callbacks == 1);
+		CHECK(nested_exits->num_callbacks == 0);
+		CHECK(gamma_entries->num_callbacks == 1);
+		CHECK(gamma_updates->num_callbacks == 1);
+		CHECK(gamma_exits->num_callbacks == 0);
+
+		state_gamma->dispatch("goto_delta");
+		CHECK(hsm->get_leaf_state() == state_delta);
+		CHECK(nested_entries->num_callbacks == 1);
+		CHECK(nested_updates->num_callbacks == 1);
+		CHECK(nested_exits->num_callbacks == 0);
+		CHECK(gamma_entries->num_callbacks == 1);
+		CHECK(gamma_updates->num_callbacks == 1);
+		CHECK(gamma_exits->num_callbacks == 1);
+		CHECK(delta_entries->num_callbacks == 1);
+		CHECK(delta_updates->num_callbacks == 0);
+		CHECK(delta_exits->num_callbacks == 0);
+
+		state_delta->dispatch(hsm->event_finished());
+		CHECK(nested_entries->num_callbacks == 1);
+		CHECK(nested_updates->num_callbacks == 1);
+		CHECK(nested_exits->num_callbacks == 1);
+		CHECK(gamma_entries->num_callbacks == 1);
+		CHECK(gamma_updates->num_callbacks == 1);
+		CHECK(gamma_exits->num_callbacks == 1);
+		CHECK(delta_entries->num_callbacks == 1);
+		CHECK(delta_updates->num_callbacks == 0);
+		CHECK(delta_exits->num_callbacks == 1);
+		CHECK(hsm->is_active() == false);
+		CHECK(hsm->get_leaf_state() == hsm);
+	}
+	SUBCASE("Test get_root()") {
+		CHECK(hsm->get_root() == hsm);
+		CHECK(state_alpha->get_root() == hsm);
+		CHECK(state_beta->get_root() == hsm);
+		CHECK(nested_hsm->get_root() == hsm);
+		CHECK(state_delta->get_root() == hsm);
+		CHECK(state_gamma->get_root() == hsm);
+	}
 
 	memdelete(agent);
 	memdelete(hsm);