diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..766c2fe
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,49 @@
+# https://github.com/shivammathur/setup-php/blob/master/README.md
+
+name: CI
+
+on:
+  push:
+    branches: [ master, dev ]
+  pull_request:
+    branches: [ master, dev ]
+
+jobs:
+  Tests:
+
+    runs-on: ubuntu-latest
+
+    strategy:
+      matrix:
+        php-version:
+          - 8.0
+          - 8.1
+
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Cache Composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ~/.composer/cache
+          key: php${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-${{ hashFiles('**/composer.json') }}
+          restore-keys: php${{ matrix.php-version }}-composer-${{ matrix.dependencies }}-
+
+      - name: Setup PHP v ${{ matrix.php-version }}
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: ${{ matrix.php-version }}
+          extensions: json, curl, tokenizer, mbstring, xdebug
+          coverage: xdebug
+          tools: composer, phpunit
+
+      - name: Install dependencies with composer
+        run: composer install --no-ansi --no-interaction --no-progress
+
+      - name: Run tests with phpunit/phpunit
+        run: vendor/bin/phpunit --coverage-clover=coverage.xml --configuration=phpunit.xml
+
+      - name: Send code coverage report to Codecov.io
+        env:
+          CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}
+        run: bash <(curl -s https://codecov.io/bash) || true
diff --git a/.github/workflows/dev.yml b/.github/workflows/dev.yml
deleted file mode 100644
index 7c70f41..0000000
--- a/.github/workflows/dev.yml
+++ /dev/null
@@ -1,25 +0,0 @@
-name: Dev build
-
-on:
-  push:
-    branches: [ dev ]
-  pull_request:
-    branches: [ dev ]
-
-jobs:
-  Tests:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Validate composer.json and composer.lock
-        uses: php-actions/composer@40-env
-        with:
-          version: 2
-          php_version: 8.0
-          only_args: --prefer-dist --no-progress
-
-      - name: Run phpunit tests
-        uses: php-actions/phpunit@v9
-        with:
-          configuration: ./phpunit.xml
diff --git a/.github/workflows/master.yml b/.github/workflows/master.yml
deleted file mode 100644
index 0e0fd58..0000000
--- a/.github/workflows/master.yml
+++ /dev/null
@@ -1,25 +0,0 @@
-name: Master build
-
-on:
-  push:
-    branches: [ master ]
-  pull_request:
-    branches: [ master ]
-
-jobs:
-  Tests:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v2
-
-      - name: Validate composer.json and composer.lock
-        uses: php-actions/composer@40-env
-        with:
-          version: 2
-          php_version: 7.4
-          only_args: --prefer-dist --no-progress
-
-      - name: Run phpunit tests
-        uses: php-actions/phpunit@v8
-        with:
-          configuration: ./phpunit.xml
diff --git a/.gitignore b/.gitignore
index 5bc0a5c..6ccbbdc 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@
 /config.php
 *cache*
 /test.php
+/.coverage-report
diff --git a/README.md b/README.md
index be5999e..e218791 100644
--- a/README.md
+++ b/README.md
@@ -10,9 +10,10 @@
 [![Master build](https://github.com/anthonyaxenov/atol-online/actions/workflows/master.yml/badge.svg)](https://github.com/anthonyaxenov/atol-online/actions/workflows/master.yml)
 [![Dev build](https://github.com/anthonyaxenov/atol-online/actions/workflows/dev.yml/badge.svg)](https://github.com/anthonyaxenov/atol-online/actions/workflows/dev.yml)
 [![Latest Stable Version](http://poser.pugx.org/axenov/atol-online/v)](https://packagist.org/packages/axenov/atol-online) 
-[![Latest Unstable Version](http://poser.pugx.org/axenov/atol-online/v/unstable)](https://packagist.org/packages/axenov/atol-online)
-[![Total Downloads](http://poser.pugx.org/axenov/atol-online/downloads)](https://packagist.org/packages/axenov/atol-online)
+[![codecov](https://codecov.io/gh/anthonyaxenov/atol-online/branch/master/graph/badge.svg?token=WR2IV7FTF0)](https://codecov.io/gh/anthonyaxenov/atol-online)
 [![License](http://poser.pugx.org/axenov/atol-online/license)](https://packagist.org/packages/axenov/atol-online)
+<!--[![Latest Unstable Version](http://poser.pugx.org/axenov/atol-online/v/unstable)](https://packagist.org/packages/axenov/atol-online)-->
+<!--[![Total Downloads](http://poser.pugx.org/axenov/atol-online/downloads)](https://packagist.org/packages/axenov/atol-online)-->
 
 Библиотека для фискализации чеков по 54-ФЗ через [облачную ККТ АТОЛ](https://online.atol.ru/).
 
@@ -63,12 +64,15 @@
 
 Файлы тестов находятся в директории `/tests` корня репозитория.
 
-Для запуска тестов необходимо перейти в корень вашего проекта и выполнить команду:
+Для запуска тестов необходимо перейти в корень репозитория и выполнить одну из команд:
 
 ```bash
-composer test
+composer test # обычное тестирование
+composer test-cov # тестирование с покрытием
 ```
 
+После тестирования с покрытием создаётся отчёт в директории `.coverage-report` в корне репозитория.
+
 ## Использование библиотеки
 
 Весь исходный код находится в директории [`/src`](/src).
diff --git a/composer.json b/composer.json
index ca6be48..c78cdf8 100644
--- a/composer.json
+++ b/composer.json
@@ -73,6 +73,6 @@
     },
     "scripts": {
         "test": "vendor/bin/phpunit --colors=always",
-        "test-cov": "vendor/bin/phpunit --coverage-html coverage"
+        "test-cov": "php -dxdebug.mode=coverage vendor/bin/phpunit --coverage-html .coverage-report"
     }
 }