diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index fae578f..48321b8 100755
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -32,7 +32,7 @@ jobs:
           force_orphan: true
           publish_branch: gh-pages
 
-  run-tests:
+  run-tests-with-coverage:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout code
@@ -43,3 +43,12 @@ jobs:
         run: sudo apt-get install gcc make
       - name: Run tests
         run: make -C test tests
+      - name: Coverage data
+        run: gcov -pb src/**/*.c
+      - name: List coverage data
+        run: |
+          tree ./
+      - name: Upload coverage to Codecov
+        uses: codecov/codecov-action@v3
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
diff --git a/.gitignore b/.gitignore
index 45e82d8..1854052 100755
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@ html
 # test coverage
 *.gcda
 *.gcno
+*.gcov
 
 # Linker output
 *.ilk
diff --git a/README.md b/README.md
index 0a74845..1ed8ee6 100755
--- a/README.md
+++ b/README.md
@@ -1,4 +1,5 @@
 ![CI Status](https://github.com/polesskiy-dev/active-object-fsm/actions/workflows/ci.yml/badge.svg?branch=main)
+[![codecov](https://codecov.io/gh/polesskiy-dev/active-object-fsm/graph/badge.svg?token=0MO4ODZ1HA)](https://codecov.io/gh/polesskiy-dev/active-object-fsm)
 [![Documentation](https://img.shields.io/badge/docs-Doxygen-blue.svg)](https://polesskiy-dev.github.io/active-object-fsm/)
 ![GitHub release (with filter)](https://img.shields.io/github/v/release/polesskiy-dev/active-object-fsm)
 
diff --git a/docs/active-object-typings.png b/docs/active-object-typings.png
deleted file mode 100755
index af69b58..0000000
Binary files a/docs/active-object-typings.png and /dev/null differ
diff --git a/test/Makefile b/test/Makefile
index b48a99d..74c00ef 100755
--- a/test/Makefile
+++ b/test/Makefile
@@ -1,5 +1,5 @@
 # Compiler
-CC = gcc -std=c99 #-Wall -Wextra -Werror -pedantic -g
+CC = gcc -std=c99 -fprofile-arcs -ftest-coverage -O0
 
 # Directories
 SRC_DIR = ../src