diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 25b0820..cccf254 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,9 +1,60 @@
-test_dmd:
-    stage: test
-    image: mmcomando/ecs_enviroment
+image: "registry.gitlab.com/mergul/bubel-ecs:latest"
+
+variables:
+    DOCKER_DRIVER: overlay2
+
+stages:
+  - build
+  - test
+  - testcov
+
+test_compile:
+    stage: build
     script:
         - source $(/script/dlang/install.sh dmd -a) && dmd --version
-        - source $(/script/dlang/install.sh dmd -a) && dub -c unittest-runner -b unittest
+        - dub build -c unittest-runner -b debug --verror
+        - dub build -c unittest-runner -b release --verror
+        - dub build -c unittest-runner-betterC -b debug --verror
+        - dub build -c unittest-runner-betterC -b release --verror
+        - deactivate
+        - source $(/script/dlang/install.sh ldc -a) && ldc2 --version
+        - dub build -c unittest-runner --compiler=ldc2 -b debug --verror
+        - dub build -c unittest-runner --compiler=ldc2 -b release --verror
+        - dub build -c unittest-runner-betterC --compiler=ldc2 -b debug --verror
+        - dub build -c unittest-runner-betterC --compiler=ldc2 -b release --verror
+        - deactivate
+    allow_failure: true
+
+test_dmd_debug:
+    stage: test    
+    script:
+        - source $(/script/dlang/install.sh dmd -a) && dmd --version
+        - dub -c unittest-runner -b debug --verror
     artifacts:
         reports:
             junit: test_report.xml
+test_dmd:
+    stage: test    
+    script:
+        - source $(/script/dlang/install.sh dmd -a) && dmd --version
+        - dub -c unittest-runner -b release --verror
+    artifacts:
+        reports:
+            junit: test_report.xml
+test_dmd_betterC:
+    stage: test
+    script:
+        - source $(/script/dlang/install.sh dmd -a) && dmd --version
+        - dub -c unittest-runner-betterC -b release --verror
+    artifacts:
+        reports:
+            junit: test_report.xml
+coverage_test_dmd:
+    stage: testcov
+    needs: ["test_dmd_debug"]
+    script:
+        - mkdir reports
+        - source $(/script/dlang/install.sh dmd -a) && dmd --version
+        - dub -c unittest-runner-cov -b debug --verror
+    after_script:
+        - bash <(curl -s https://codecov.io/bash) -s reports -t 1a0c0169-a721-4085-8252-fed4755dcd8c
diff --git a/README.md b/README.md
index 76fff75..d3f6816 100644
--- a/README.md
+++ b/README.md
@@ -1,5 +1,5 @@
 # Dynamic Entity Component System
 [![pipeline status](https://gitlab.com/Mergul/bubel-ecs/badges/master/pipeline.svg)](https://gitlab.com/Mergul/bubel-ecs/-/commits/master)
-[![coverage report](https://gitlab.com/Mergul/bubel-ecs/badges/master/coverage.svg)](https://gitlab.com/Mergul/bubel-ecs/-/commits/master)
+[![codecov](https://codecov.io/gl/Mergul/bubel-ecs/branch/master/graph/badge.svg?token=Unm0TJhFoW)](https://codecov.io/gl/Mergul/bubel-ecs)
 
-Entity-Component-System implementation in D language.
\ No newline at end of file
+Entity-Component-System implementation in D language.
diff --git a/codecov.yml b/codecov.yml
new file mode 100644
index 0000000..a6afdbc
--- /dev/null
+++ b/codecov.yml
@@ -0,0 +1,3 @@
+ignore:
+  - "tests/*"
+  - "**/traits*"
\ No newline at end of file
diff --git a/source/ecs/manager.d b/source/ecs/manager.d
index 1b9b959..5ec5b87 100644
--- a/source/ecs/manager.d
+++ b/source/ecs/manager.d
@@ -442,11 +442,12 @@ export struct EntityManager
 
         static struct ComponentsCounts
         {
-            uint readonly;
-            uint mutable;
-            uint excluded;
-            uint optional;
-            uint req;
+            //one more than should be to prevent null arrays (zero length arrays)
+            uint readonly = 1;
+            uint mutable = 1;
+            uint excluded = 1;
+            uint optional = 1;
+            uint req = 1;
         }
 
         static ComponentsCounts getComponentsCounts()()