diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 35d2ea5..ead22e0 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -61,4 +61,11 @@ jobs:
 
       - name: Run tests
         run: |
-          vendor/bin/phpunit
+          vendor/bin/phpunit --coverage-clover build/logs/clover.xml
+
+      - name: Upload coverage results to Coveralls
+        continue-on-error: true
+        env:
+          COVERALLS_REPO_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: |
+          php vendor/bin/php-coveralls --coverage_clover=build/logs/clover.xml -v
diff --git a/.gitignore b/.gitignore
index ce7bff7..ec06cc6 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,3 +3,4 @@
 /composer.lock
 /phpunit.xml
 /vendor/
+/build/
diff --git a/.php_cs.dist b/.php_cs.dist
index 8a2af04..d3a2c6d 100644
--- a/.php_cs.dist
+++ b/.php_cs.dist
@@ -22,6 +22,7 @@ return PhpCsFixer\Config::create()
         'combine_consecutive_unsets' => true,
         'comment_to_phpdoc' => true,
         'compact_nullable_typehint' => true,
+        'declare_strict_types' => false,
         'escape_implicit_backslashes' => true,
         'explicit_indirect_variable' => true,
         'explicit_string_variable' => true,
diff --git a/composer.json b/composer.json
index 24719e2..10433c0 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,8 @@
         "phpunit/phpunit": "^4.8.36 || ^5.7.27 || ^6.5.14 || ^7.5.20 || ^8.0 || ^9.0"
     },
     "require-dev": {
-        "friendsofphp/php-cs-fixer": "^2"
+        "friendsofphp/php-cs-fixer": "^2",
+        "php-coveralls/php-coveralls": "^2.4"
     },
     "config": {
         "optimize-autoloader": true,
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
index c643ce0..0493a2b 100644
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,5 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <phpunit bootstrap="./vendor/autoload.php">
+    <filter>
+        <whitelist>
+            <directory>src</directory>
+        </whitelist>
+    </filter>
     <testsuites>
         <testsuite name="Default">
             <directory>tests</directory>
diff --git a/src/PolyfillTrait.php b/src/PolyfillTrait.php
index 7c9e840..0381233 100644
--- a/src/PolyfillTrait.php
+++ b/src/PolyfillTrait.php
@@ -14,14 +14,7 @@
 if (version_compare(\PHPUnit\Runner\Version::id(), '7.0.0') < 0) {
     trait PolyfillTrait
     {
-        public function expectException($exception)
-        {
-            if (\is_callable(['parent', 'expectException'])) {
-                parent::expectException($exception);
-            } else {
-                $this->setExpectedException($exception);
-            }
-        }
+        use PolyfillTrait6;
     }
 } else {
     trait PolyfillTrait
diff --git a/src/PolyfillTrait6.php b/src/PolyfillTrait6.php
new file mode 100644
index 0000000..9cdbbdc
--- /dev/null
+++ b/src/PolyfillTrait6.php
@@ -0,0 +1,137 @@
+<?php
+
+/*
+ * This file is part of PHPUnit Good Practices.
+ *
+ * (c) Dariusz Rumiński <dariusz.ruminski@gmail.com>
+ *
+ * This source file is subject to the MIT license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace PHPUnitGoodPractices\Polyfill;
+
+/**
+ * @internal
+ */
+trait PolyfillTrait6
+{
+    public function expectException($exception)
+    {
+        if (\is_callable(['parent', 'expectException'])) {
+            parent::expectException($exception);
+        } else {
+            $this->setExpectedException($exception);
+        }
+    }
+
+    public function expectExceptionMessageMatches($regexp)
+    {
+        if (\is_callable(['parent', 'expectExceptionMessageMatches'])) {
+            parent::expectExceptionMessageMatches($regexp);
+
+            return;
+        }
+
+        // In some PHPUnit versions just setting an expectation for specific
+        // expection message won't trigger exception handler. Therefore we need
+        // to set the expected type, but trying to keep the type.
+        if (\is_callable(['parent', 'getExpectedException'])) {
+            $expectedException = parent::getExpectedException(); // This is an @internal method.
+        }
+
+        if (null === $expectedException) {
+            $expectedException = \Exception::class;
+        }
+
+        $this->expectException($expectedException);
+
+        if (\is_callable(['parent', 'expectExceptionMessageRegExp'])) {
+            // Method available since Release 5.2.0
+            $this->expectExceptionMessageRegExp($regexp);
+        } else {
+            $this->setExpectedExceptionRegExp($expectedException, $regexp);
+        }
+    }
+
+    public static function assertIsArray($actual, $message = '')
+    {
+        if (\is_callable(['parent', 'assertIsArray'])) {
+            parent::assertIsArray($actual, $message);
+        } else {
+            static::assertInternalType('array', $actual, $message);
+        }
+    }
+
+    public static function assertIsString($actual, $message = '')
+    {
+        if (\is_callable(['parent', 'assertIsString'])) {
+            parent::assertIsString($actual, $message);
+        } else {
+            static::assertInternalType('string', $actual, $message);
+        }
+    }
+
+    public static function assertIsBool($actual, $message = '')
+    {
+        if (\is_callable(['parent', 'assertIsBool'])) {
+            parent::assertIsBool($actual, $message);
+        } else {
+            static::assertInternalType('bool', $actual, $message);
+        }
+    }
+
+    public static function assertIsCallable($actual, $message = '')
+    {
+        if (\is_callable(['parent', 'assertIsCallable'])) {
+            parent::assertIsCallable($actual, $message);
+        } else {
+            static::assertInternalType('callable', $actual, $message);
+        }
+    }
+
+    public static function assertIsInt($actual, $message = '')
+    {
+        if (\is_callable(['parent', 'assertIsInt'])) {
+            parent::assertIsInt($actual, $message);
+        } else {
+            static::assertInternalType('int', $actual, $message);
+        }
+    }
+
+    public static function assertMatchesRegularExpression($pattern, $string, $message = '')
+    {
+        if (\is_callable(['parent', 'assertMatchesRegularExpression'])) {
+            parent::assertMatchesRegularExpression($pattern, $string, $message);
+        } else {
+            static::assertRegExp($pattern, $string, $message);
+        }
+    }
+
+    public static function assertStringContainsString($needle, $haystack, $message = '')
+    {
+        if (\is_callable(['parent', 'assertStringContainsString'])) {
+            parent::assertStringContainsString($needle, $haystack, $message);
+        } else {
+            static::assertContains($needle, $haystack, $message);
+        }
+    }
+
+    public static function assertStringNotContainsString($needle, $haystack, $message = '')
+    {
+        if (\is_callable(['parent', 'assertStringNotContainsString'])) {
+            parent::assertStringNotContainsString($needle, $haystack, $message);
+        } else {
+            static::assertNotContains($needle, $haystack, $message);
+        }
+    }
+
+    public static function assertFileDoesNotExist($filename, $message = '')
+    {
+        if (\is_callable(['parent', 'assertFileDoesNotExist'])) {
+            parent::assertFileDoesNotExist($filename, $message);
+        } else {
+            static::assertFileNotExists($filename, $message);
+        }
+    }
+}
diff --git a/src/PolyfillTrait7.php b/src/PolyfillTrait7.php
index a023381..7157399 100644
--- a/src/PolyfillTrait7.php
+++ b/src/PolyfillTrait7.php
@@ -26,4 +26,31 @@ public function expectException(string $exception): void
             $this->setExpectedException($exception);
         }
     }
+
+    public function expectExceptionMessageMatches(string $regexp): void
+    {
+        if (\is_callable(['parent', 'expectExceptionMessageMatches'])) {
+            parent::expectExceptionMessageMatches($regexp);
+        } else {
+            $this->expectExceptionMessageRegExp($regexp);
+        }
+    }
+
+    public static function assertMatchesRegularExpression(string $pattern, string $string, string $message = ''): void
+    {
+        if (\is_callable(['parent', 'assertMatchesRegularExpression'])) {
+            parent::assertMatchesRegularExpression($pattern, $string, $message);
+        } else {
+            static::assertRegExp($pattern, $string, $message);
+        }
+    }
+
+    public static function assertFileDoesNotExist(string $filename, string $message = ''): void
+    {
+        if (\is_callable(['parent', 'assertFileDoesNotExist'])) {
+            parent::assertFileDoesNotExist($filename, $message);
+        } else {
+            static::assertFileNotExists($filename, $message);
+        }
+    }
 }
diff --git a/tests/PolyfillTest.php b/tests/PolyfillTest.php
index 45e73bb..aa60544 100644
--- a/tests/PolyfillTest.php
+++ b/tests/PolyfillTest.php
@@ -23,6 +23,57 @@ public function testExpectException()
         $this->expectException(\RuntimeException::class);
 
         throw new \RuntimeException();
-        $this->fail();
+    }
+
+    public function testExpectExceptionMessageMatches()
+    {
+        $this->expectExceptionMessageMatches('/example/');
+
+        throw new \RuntimeException('example');
+    }
+
+    public function testAssertIsArray()
+    {
+        $this->assertIsArray([]);
+    }
+
+    public function testAssertIsString()
+    {
+        $this->assertIsString('');
+    }
+
+    public function testAssertIsBool()
+    {
+        $this->assertIsBool(true);
+    }
+
+    public function testAssertIsCallable()
+    {
+        $this->assertIsCallable([$this, 'testAssertIsCallable']);
+    }
+
+    public function testAssertIsInt()
+    {
+        $this->assertIsInt(1);
+    }
+
+    public function testAssertMatchesRegularExpression()
+    {
+        $this->assertMatchesRegularExpression('/\d/', '123');
+    }
+
+    public function testAssertStringContainsString()
+    {
+        $this->assertStringContainsString('test', 'testing');
+    }
+
+    public function testAssertStringNotContainsString()
+    {
+        $this->assertStringNotContainsString('foobar', 'testing');
+    }
+
+    public function testAssertFileDoesNotExist()
+    {
+        $this->assertFileDoesNotExist('invalid');
     }
 }