diff --git a/src/darkleaf/di/core.clj b/src/darkleaf/di/core.clj
index 6d3b2eb4..230b2cf3 100644
--- a/src/darkleaf/di/core.clj
+++ b/src/darkleaf/di/core.clj
@@ -805,6 +805,7 @@
               cached-obj
               (p/build factory deps)))
           (demolish [_ obj]
-            (if (identical? cached-obj obj)
-              nil
-              (p/demolish factory obj))))))))
+            ;;todo: add test
+            #_(if (identical? cached-obj obj)
+                nil
+                (p/demolish factory obj))))))))
diff --git a/test/darkleaf/di/cache_test.clj b/test/darkleaf/di/cache_test.clj
new file mode 100644
index 00000000..2b8af4a7
--- /dev/null
+++ b/test/darkleaf/di/cache_test.clj
@@ -0,0 +1,101 @@
+(ns darkleaf.di.cache-test
+  (:require
+   [clojure.test :as t]
+   [darkleaf.di.core :as di]))
+
+(set! *warn-on-reflection* true)
+
+(defn a
+  {::di/kind :component}
+  []
+  {:name :a
+   :obj  (Object.)})
+
+(t/deftest a-test
+  (with-open [main      (di/start {:root `a :cache ::di/cache}
+                                  (di/collect-cache))
+              secondary (di/start {:root `a}
+                                  (di/use-cache (:cache main)))]
+    (t/is (identical? (-> main      :root)
+                      (-> secondary :root)))))
+
+(defn b
+  {::di/kind :component}
+  [{conf "B_CONF"}]
+  {:name :b
+   :conf conf
+   :obj  (Object.)})
+
+(t/deftest b-test
+  (with-open [main      (di/start {:root `b :cache ::di/cache}
+                                  {"B_CONF" "conf"}
+                                  ;; должен быть последним в цепочке, чтобы закешировать все
+                                  (di/collect-cache))
+              secondary (di/start {:root `b}
+                                  (di/use-cache (:cache main)))]
+    (t/is (identical? (-> main      :root)
+                      (-> secondary :root)))))
+
+(t/deftest b-changed-test
+  (with-open [main      (di/start {:root `b :cache ::di/cache}
+                                  {"B_CONF" "conf"}
+                                  (di/collect-cache))
+              secondary (di/start {:root `b}
+                                  ;; должен быть первым, чтобы его можно было переопределять
+                                  (di/use-cache (:cache main))
+                                  {"B_CONF" "changed"})]
+    (t/is (not (identical? (-> main      :root)
+                           (-> secondary :root))))))
+
+(defn c
+  {::di/kind :component}
+  [{a `a, b `b}]
+  {:name :c
+   :a    a
+   :b    b
+   :obj  (Object.)})
+
+(t/deftest c-test
+  (with-open [main      (di/start {:root `c :cache ::di/cache}
+                                  {"B_CONF" "conf"}
+                                  (di/collect-cache))
+              secondary (di/start {:root `c}
+                                  (di/use-cache (:cache main)))]
+    (t/is (identical? (-> main      :root)
+                      (-> secondary :root)))))
+
+(t/deftest c-changed-test
+  (with-open [main      (di/start {:root `c :cache ::di/cache}
+                                  {"B_CONF" "conf"}
+                                  (di/collect-cache))
+              secondary (di/start {:root `c}
+                                  (di/use-cache (:cache main))
+                                  {"B_CONF" "changed"})]
+    (t/is (not (identical? (-> main      :root)
+                           (-> secondary :root))))
+    (t/is (= :c
+             (-> main      :root :name)
+             (-> secondary :root :name)))
+    (t/is (identical? (-> main      :root :a)
+                      (-> secondary :root :a)))
+    (t/is (not (identical? (-> main      :root :b)
+                           (-> secondary :root :b))))
+    ;; надо ли проверять?
+    (t/is (not (identical? (-> main      :root :obj)
+                           (-> secondary :root :obj))))))
+
+(t/deftest invalid-cache-test
+  (let [main (di/start {:root `c :cache ::di/cache}
+                       {"B_CONF" "conf"}
+                       (di/collect-cache))
+        _    (di/stop main)]
+    (t/is (thrown? IllegalStateException
+                   (di/start `c
+                             (di/use-cache (:cache main)))))))
+
+(t/deftest not-recursive-test
+  (with-open [main (di/start {:root `c :cache ::di/cache}
+                             {"B_CONF" "conf"}
+                             (di/collect-cache))]
+    (t/try-expr "must not be recrusive"
+                (prn-str (:cache main)))))