diff --git a/lib/icinga/dependency.cpp b/lib/icinga/dependency.cpp
index bfb91d226..7dd90f5e5 100644
--- a/lib/icinga/dependency.cpp
+++ b/lib/icinga/dependency.cpp
@@ -201,3 +201,13 @@ void Dependency::ValidateStates(const Lazy<Array::Ptr>& lvalue, const Validation
 		BOOST_THROW_EXCEPTION(ValidationError(this, { "states" }, "State filter is invalid for service dependency."));
 }
 
+void Dependency::SetParent(intrusive_ptr<Checkable> parent)
+{
+	m_Parent = parent;
+}
+
+void Dependency::SetChild(intrusive_ptr<Checkable> child)
+{
+	m_Child = child;
+}
+
diff --git a/lib/icinga/dependency.hpp b/lib/icinga/dependency.hpp
index 6a80d84f5..bc3ae5388 100644
--- a/lib/icinga/dependency.hpp
+++ b/lib/icinga/dependency.hpp
@@ -37,6 +37,10 @@ public:
 	static void EvaluateApplyRules(const intrusive_ptr<Host>& host);
 	static void EvaluateApplyRules(const intrusive_ptr<Service>& service);
 
+	/* Note: Only use them for unit test mocks. Prefer OnConfigLoaded(). */
+	void SetParent(intrusive_ptr<Checkable> parent);
+	void SetChild(intrusive_ptr<Checkable> child);
+
 protected:
 	void OnConfigLoaded() override;
 	void OnAllConfigLoaded() override;
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index bfcd83ffd..8bb12e365 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -25,6 +25,7 @@ set(base_test_SOURCES
   base-value.cpp
   config-ops.cpp
   icinga-checkresult.cpp
+  icinga-dependencies.cpp
   icinga-legacytimeperiod.cpp
   icinga-macros.cpp
   icinga-notification.cpp
@@ -126,6 +127,7 @@ add_boost_test(base
     icinga_checkresult/service_3attempts
     icinga_checkresult/host_flapping_notification
     icinga_checkresult/service_flapping_notification
+    icinga_dependencies/multi_parent
     icinga_notification/strings
     icinga_notification/state_filter
     icinga_notification/type_filter
diff --git a/test/icinga-dependencies.cpp b/test/icinga-dependencies.cpp
new file mode 100644
index 000000000..b31f540b1
--- /dev/null
+++ b/test/icinga-dependencies.cpp
@@ -0,0 +1,89 @@
+/* Icinga 2 | (c) 2020 Icinga GmbH | GPLv2+ */
+
+#include "icinga/host.hpp"
+#include "icinga/dependency.hpp"
+#include <BoostTestTargetConfig.h>
+#include <iostream>
+
+using namespace icinga;
+
+BOOST_AUTO_TEST_SUITE(icinga_dependencies)
+
+BOOST_AUTO_TEST_CASE(multi_parent)
+{
+	/* One child host, two parent hosts. Simulate multi-parent dependencies. */
+	std::cout << "Testing reachability for multi parent dependencies." << std::endl;
+
+	/*
+	 * Our mock requires:
+	 * - SetParent/SetChild functions for the dependency
+	 * - Parent objects need a CheckResult object
+	 * - Dependencies need a StateFilter
+	 */
+	Host::Ptr parentHost1 = new Host();
+	parentHost1->SetActive(true);
+	parentHost1->SetMaxCheckAttempts(1);
+	parentHost1->Activate();
+	parentHost1->SetAuthority(true);
+	parentHost1->SetStateRaw(ServiceCritical);
+	parentHost1->SetStateType(StateTypeHard);
+	parentHost1->SetLastCheckResult(new CheckResult());
+
+	Host::Ptr parentHost2 = new Host();
+	parentHost2->SetActive(true);
+	parentHost2->SetMaxCheckAttempts(1);
+	parentHost2->Activate();
+	parentHost2->SetAuthority(true);
+	parentHost2->SetStateRaw(ServiceOK);
+	parentHost2->SetStateType(StateTypeHard);
+	parentHost2->SetLastCheckResult(new CheckResult());
+
+	Host::Ptr childHost = new Host();
+	childHost->SetActive(true);
+	childHost->SetMaxCheckAttempts(1);
+	childHost->Activate();
+	childHost->SetAuthority(true);
+	childHost->SetStateRaw(ServiceOK);
+	childHost->SetStateType(StateTypeHard);
+
+	/* Build the dependency tree. */
+	Dependency::Ptr dep1 = new Dependency();
+
+	dep1->SetParent(parentHost1);
+	dep1->SetChild(childHost);
+	dep1->SetStateFilter(StateFilterUp);
+
+	// Reverse dependencies
+        childHost->AddDependency(dep1);
+        parentHost1->AddReverseDependency(dep1);
+
+	Dependency::Ptr dep2 = new Dependency();
+
+	dep2->SetParent(parentHost2);
+	dep2->SetChild(childHost);
+	dep2->SetStateFilter(StateFilterUp);
+
+	// Reverse dependencies
+        childHost->AddDependency(dep2);
+        parentHost2->AddReverseDependency(dep2);
+
+
+	/* Test the reachability from this point.
+	 * parentHost1 is DOWN, parentHost2 is UP.
+	 * Expected result: childHost is reachable.
+	 */
+	parentHost1->SetStateRaw(ServiceCritical); // parent Host 1 DOWN
+	parentHost2->SetStateRaw(ServiceOK);       // parent Host 2 UP
+
+	BOOST_CHECK(childHost->IsReachable() == true);
+
+	/* parentHost1 is DOWN, parentHost2 is DOWN.
+	 * Expected result: childHost is unreachable.
+	 */
+	parentHost1->SetStateRaw(ServiceCritical); // parent Host 1 DOWN
+	parentHost2->SetStateRaw(ServiceCritical); // parent Host 2 DOWN
+
+	BOOST_CHECK(childHost->IsReachable() == false);
+}
+
+BOOST_AUTO_TEST_SUITE_END()