diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 000000000..571d8af96
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,263 @@
+name: Spout CI
+
+on: push
+
+jobs:
+  tests-on-php-latest:
+    strategy:
+      matrix:
+        operating-system: [ubuntu-latest, windows-latest, macos-latest]
+    runs-on: ${{ matrix.operating-system }}
+    name: Tests - PHP 8.0 on ${{ matrix.operating-system }}
+    env:
+      extensions: zip, xmlreader, dom
+      cache-key: cache-matrix-v1 # can be any string, change to clear the extension cache.
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+          key: ${{ env.cache-key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2 #https://github.com/shivammathur/setup-php
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          # Use composer.json for key, if composer.lock is not committed.
+          # key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Test with phpunit
+        run: vendor/bin/phpunit --no-coverage
+
+  tests-on-older-php:
+    strategy:
+      matrix:
+        php-versions: ['7.2', '7.3', '7.4']
+    runs-on: ubuntu-latest
+    name: Tests - PHP ${{ matrix.php-versions }}
+    env:
+      extensions: zip, xmlreader, dom
+      cache-key: cache-matrix-v1 # can be any string, change to clear the extension cache.
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: ${{ matrix.php-versions }}
+          extensions: ${{ env.extensions }}
+          key: ${{ env.cache-key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2 #https://github.com/shivammathur/setup-php
+        with:
+          php-version: ${{ matrix.php-versions }}
+          extensions: ${{ env.extensions }}
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          # Use composer.json for key, if composer.lock is not committed.
+          # key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Test with phpunit
+        run: vendor/bin/phpunit --no-coverage
+
+  code-coverage:
+    name: Code coverage
+    runs-on: ubuntu-latest
+    env:
+      extensions: zip, xmlreader, dom
+      cache-key: cache-single-v1 # can be any string, change to clear the extension cache.
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: '7.4'
+          extensions: ${{ env.extensions }}
+          key: ${{ env.cache-key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '7.4'
+          extensions: ${{ env.extensions }}
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          # Use composer.json for key, if composer.lock is not committed.
+          # key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Run Tests with Code Coverage
+        run: vendor/bin/phpunit --coverage-clover=coverage.clover
+
+        # TODO: Send coverage data to a new provider
+
+  coding-style:
+    name: Coding Style
+    runs-on: ubuntu-latest
+    env:
+      extensions: zip, xmlreader, dom
+      cache-key: cache-single-v1 # can be any string, change to clear the extension cache.
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+          key: ${{ env.cache-key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          # Use composer.json for key, if composer.lock is not committed.
+          # key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Run PHP-CS-Fixer
+        run: vendor/bin/php-cs-fixer fix --verbose --diff --dry-run --diff-format=udiff
+
+  static-analysis:
+    name: Static Analysis
+    runs-on: ubuntu-latest
+    env:
+      extensions: zip, xmlreader, dom
+      cache-key: cache-single-v1 # can be any string, change to clear the extension cache.
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v2
+
+      - name: Setup cache environment
+        id: extcache
+        uses: shivammathur/cache-extensions@v1
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+          key: ${{ env.cache-key }}
+
+      - name: Cache extensions
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.extcache.outputs.dir }}
+          key: ${{ steps.extcache.outputs.key }}
+          restore-keys: ${{ steps.extcache.outputs.key }}
+
+      - name: Setup PHP
+        uses: shivammathur/setup-php@v2
+        with:
+          php-version: '8.0'
+          extensions: ${{ env.extensions }}
+          tools: phpstan
+
+      - name: Get composer cache directory
+        id: composer-cache
+        run: echo "::set-output name=dir::$(composer config cache-files-dir)"
+
+      - name: Cache composer dependencies
+        uses: actions/cache@v2
+        with:
+          path: ${{ steps.composer-cache.outputs.dir }}
+          # Use composer.json for key, if composer.lock is not committed.
+          # key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.json') }}
+          key: ${{ runner.os }}-composer-${{ hashFiles('**/composer.lock') }}
+          restore-keys: ${{ runner.os }}-composer-
+
+      - name: Install dependencies
+        run: composer install --no-progress --prefer-dist --optimize-autoloader
+
+      - name: Static Analysis using PHPStan
+        run: phpstan analyse --no-progress src/
diff --git a/.php_cs.dist b/.php-cs-fixer.dist.php
similarity index 97%
rename from .php_cs.dist
rename to .php-cs-fixer.dist.php
index 9879a529c..c7e7f81df 100644
--- a/.php_cs.dist
+++ b/.php-cs-fixer.dist.php
@@ -19,7 +19,7 @@
         'no_break_comment' => ['comment_text' => 'do nothing'],
         'no_empty_phpdoc' => false,
         'no_null_property_initialization' => true,
-        'no_short_echo_tag' => true,
+        'echo_tag_syntax' => false,
         'no_superfluous_elseif' => true,
         'no_superfluous_phpdoc_tags' => false,
         'no_unneeded_control_parentheses' => ['statements' => ['break', 'clone', 'continue', 'echo_print', 'switch_case', 'yield']],
@@ -37,7 +37,7 @@
         'phpdoc_types_order' => ['null_adjustment' => 'always_last', 'sort_algorithm' => 'none'],
         'phpdoc_separation' => false,
         'protected_to_private' => true,
-        'psr4' => true,
+        'psr_autoloading' => true,
         'return_type_declaration' => ['space_before' => 'one'],
         'semicolon_after_instruction' => true,
         'simplified_null_return' => false,
diff --git a/.travis.yml b/.travis.yml
deleted file mode 100644
index 365ee595f..000000000
--- a/.travis.yml
+++ /dev/null
@@ -1,61 +0,0 @@
-dist: bionic
-sudo: false
-
-language: php
-
-matrix:
-  include:
-    - php: 7.2
-      env: WITH_PHPUNIT=true
-    - php: 7.3
-      env: WITH_PHPUNIT=true
-    - php: 7.3
-      env: WITH_PHPUNIT=true WITH_COVERAGE=true
-    - php: 7.4
-      env: WITH_PHPUNIT=true
-    - php: 8.0
-      env: WITH_PHPUNIT=true
-
-
-cache:
-  directories:
-    - $HOME/.composer/cache
-    - $HOME/.php-cs-fixer
-
-before_install:
-  - |
-    if [[ "$WITH_COVERAGE" != "true" ]]; then
-        phpenv config-rm xdebug.ini
-    fi
-    if [[ "$WITH_CS" != "true" ]]; then
-        composer remove friendsofphp/php-cs-fixer --dev --no-update
-    fi
-  - composer validate
-
-install:
-  - composer install --no-interaction --prefer-source
-
-before_script:
-  - mkdir -p "$HOME/.php-cs-fixer"
-  - mkdir -p build/logs
-
-script:
-  - |
-    if [[ "$WITH_CS" == "true" ]]; then
-        vendor/bin/php-cs-fixer fix --config=.php_cs.dist --verbose --diff --dry-run --diff-format=udiff
-    fi
-  - |
-    if [[ "$WITH_PHPUNIT" == "true" ]]; then
-        if [[ "$WITH_COVERAGE" == "true" ]]; then
-            vendor/bin/phpunit --coverage-clover=build/logs/coverage.clover
-        else
-            vendor/bin/phpunit --no-coverage
-        fi
-    fi
-
-after_script:
-  - |
-    if [[ "$WITH_COVERAGE" == "true" ]]; then
-      wget https://scrutinizer-ci.com/ocular.phar
-      php ocular.phar code-coverage:upload --format=php-clover build/logs/coverage.clover
-    fi
diff --git a/appveyor.yml b/appveyor.yml
deleted file mode 100644
index c5fe2ec75..000000000
--- a/appveyor.yml
+++ /dev/null
@@ -1,35 +0,0 @@
-build: false
-clone_depth: 1
-
-environment:
-  PHP_CHOCO_VERSION: 7.2.0
-  PHP_CACHE_DIR: C:\tools\php
-
-cache:
-  - '%PHP_CACHE_DIR% -> appveyor.yml'
-
-init:
-  - SET PATH=%PHP_CACHE_DIR%;%PATH%
-  - SET COMPOSER_CACHE_DIR=%PHP_CACHE_DIR%
-  - SET COMPOSER_NO_INTERACTION=1
-  - SET PHP=0
-  - SET ANSICON=121x90 (121x90)
-
-install:
-  - IF EXIST %PHP_CACHE_DIR% (SET PHP=1)
-  - IF %PHP%==0 cinst php -y --version %PHP_CHOCO_VERSION%  --params "/InstallDir:%PHP_CACHE_DIR%"
-  - IF %PHP%==0 cinst composer -y --ia "/DEV=%PHP_CACHE_DIR%"
-  - cd %PHP_CACHE_DIR%
-  - IF %PHP%==0 copy php.ini-production php.ini
-  - IF %PHP%==0 echo extension_dir=ext >> php.ini
-  - IF %PHP%==0 echo extension=php_fileinfo.dll >> php.ini
-  - IF %PHP%==0 echo extension=php_mbstring.dll >> php.ini
-  - IF %PHP%==0 echo extension=php_openssl.dll >> php.ini
-  - php -v
-  - IF %PHP%==0 (composer --version) ELSE (composer self-update)
-  - cd %APPVEYOR_BUILD_FOLDER%
-  - composer install --prefer-dist --no-progress
-
-test_script:
-  - cd %APPVEYOR_BUILD_FOLDER%
-  - vendor\bin\phpunit --colors=always
diff --git a/src/Spout/Reader/Common/Creator/ReaderEntityFactory.php b/src/Spout/Reader/Common/Creator/ReaderEntityFactory.php
index 06a9d9fbe..3b51102aa 100644
--- a/src/Spout/Reader/Common/Creator/ReaderEntityFactory.php
+++ b/src/Spout/Reader/Common/Creator/ReaderEntityFactory.php
@@ -35,6 +35,7 @@ public static function createCSVReader()
             return ReaderFactory::createFromType(Type::CSV);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 
@@ -49,6 +50,7 @@ public static function createXLSXReader()
             return ReaderFactory::createFromType(Type::XLSX);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 
@@ -63,6 +65,7 @@ public static function createODSReader()
             return ReaderFactory::createFromType(Type::ODS);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 }
diff --git a/src/Spout/Writer/Common/Creator/WriterEntityFactory.php b/src/Spout/Writer/Common/Creator/WriterEntityFactory.php
index 8e43c31e3..f07e5f013 100644
--- a/src/Spout/Writer/Common/Creator/WriterEntityFactory.php
+++ b/src/Spout/Writer/Common/Creator/WriterEntityFactory.php
@@ -50,6 +50,7 @@ public static function createCSVWriter()
             return WriterFactory::createFromType(Type::CSV);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 
@@ -64,6 +65,7 @@ public static function createXLSXWriter()
             return WriterFactory::createFromType(Type::XLSX);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 
@@ -78,6 +80,7 @@ public static function createODSWriter()
             return WriterFactory::createFromType(Type::ODS);
         } catch (UnsupportedTypeException $e) {
             // should never happen
+            return null;
         }
     }
 
diff --git a/tests/Spout/Reader/CSV/ReaderTest.php b/tests/Spout/Reader/CSV/ReaderTest.php
index 684b04542..1d092f062 100644
--- a/tests/Spout/Reader/CSV/ReaderTest.php
+++ b/tests/Spout/Reader/CSV/ReaderTest.php
@@ -237,7 +237,9 @@ public function testReadShouldSupportEscapedCharacters()
     public function testReadShouldNotTruncateLineBreak()
     {
         $allRows = $this->getAllRowsForFile('csv_with_line_breaks.csv');
-        $this->assertEquals("This is,\na comma", $allRows[0][0]);
+
+        $newLine = PHP_EOL; // to support both Unix and Windows
+        $this->assertEquals("This is,{$newLine}a comma", $allRows[0][0]);
     }
 
     /**
@@ -419,10 +421,11 @@ public function testReaderShouldNotTrimCellValues()
     {
         $allRows = $this->getAllRowsForFile('sheet_with_untrimmed_strings.csv');
 
+        $newLine = PHP_EOL; // to support both Unix and Windows
         $expectedRows = [
             ['A'],
             [' A '],
-            ["\n\tA\n\t"],
+            ["$newLine\tA$newLine\t"],
         ];
 
         $this->assertEquals($expectedRows, $allRows, 'Cell values should not be trimmed');
diff --git a/tests/Spout/Writer/ODS/WriterTest.php b/tests/Spout/Writer/ODS/WriterTest.php
index a9aaa0e39..d9295bb61 100644
--- a/tests/Spout/Writer/ODS/WriterTest.php
+++ b/tests/Spout/Writer/ODS/WriterTest.php
@@ -291,12 +291,19 @@ public function testAddRowShouldSupportFloatValuesInDifferentLocale()
             // Installed locales differ from one system to another, so we can't pick
             // a given locale.
             $supportedLocales = explode("\n", shell_exec('locale -a'));
+            $foundCommaLocale = false;
             foreach ($supportedLocales as $supportedLocale) {
                 \setlocale(LC_ALL, $supportedLocale);
                 if (\localeconv()['decimal_point'] === ',') {
+                    $foundCommaLocale = true;
                     break;
                 }
             }
+
+            if (!$foundCommaLocale) {
+                $this->markTestSkipped('No locale with comma decimal separator');
+            }
+
             $this->assertEquals(',', \localeconv()['decimal_point']);
 
             $fileName = 'test_add_row_should_support_float_values_in_different_locale.xlsx';
@@ -306,8 +313,8 @@ public function testAddRowShouldSupportFloatValuesInDifferentLocale()
 
             $this->writeToODSFile($dataRows, $fileName);
 
-            $this->assertValueWasNotWrittenToSheet($fileName, 1, "1234,5");
-            $this->assertValueWasWrittenToSheet($fileName, 1, "1234.5");
+            $this->assertValueWasNotWrittenToSheet($fileName, 1, '1234,5');
+            $this->assertValueWasWrittenToSheet($fileName, 1, '1234.5');
         } finally {
             // reset locale
             \setlocale(LC_ALL, $previousLocale);
@@ -511,6 +518,10 @@ public function testAddRowShouldKeepNewLines()
      */
     public function testGeneratedFileShouldHaveTheCorrectMimeType()
     {
+        if (!function_exists('finfo')) {
+            $this->markTestSkipped('finfo is not available on this system (possibly running on Windows where the DLL needs to be added explicitly to the php.ini)');
+        }
+
         $fileName = 'test_mime_type.ods';
         $resourcePath = $this->getGeneratedResourcePath($fileName);
         $dataRow = ['foo'];
diff --git a/tests/Spout/Writer/XLSX/WriterTest.php b/tests/Spout/Writer/XLSX/WriterTest.php
index 26b379257..246950681 100644
--- a/tests/Spout/Writer/XLSX/WriterTest.php
+++ b/tests/Spout/Writer/XLSX/WriterTest.php
@@ -406,12 +406,19 @@ public function testAddRowShouldSupportFloatValuesInDifferentLocale()
             // Installed locales differ from one system to another, so we can't pick
             // a given locale.
             $supportedLocales = explode("\n", shell_exec('locale -a'));
+            $foundCommaLocale = false;
             foreach ($supportedLocales as $supportedLocale) {
                 \setlocale(LC_ALL, $supportedLocale);
                 if (\localeconv()['decimal_point'] === ',') {
+                    $foundCommaLocale = true;
                     break;
                 }
             }
+
+            if (!$foundCommaLocale) {
+                $this->markTestSkipped('No locale with comma decimal separator');
+            }
+
             $this->assertEquals(',', \localeconv()['decimal_point']);
 
             $fileName = 'test_add_row_should_support_float_values_in_different_locale.xlsx';
@@ -421,8 +428,8 @@ public function testAddRowShouldSupportFloatValuesInDifferentLocale()
 
             $this->writeToXLSXFile($dataRows, $fileName, $shouldUseInlineStrings = false);
 
-            $this->assertInlineDataWasNotWrittenToSheet($fileName, 1, "1234,5");
-            $this->assertInlineDataWasWrittenToSheet($fileName, 1, "1234.5");
+            $this->assertInlineDataWasNotWrittenToSheet($fileName, 1, '1234,5');
+            $this->assertInlineDataWasWrittenToSheet($fileName, 1, '1234.5');
         } finally {
             // reset locale
             \setlocale(LC_ALL, $previousLocale);
@@ -568,6 +575,10 @@ public function testAddRowShouldEscapeControlCharacters()
      */
     public function testGeneratedFileShouldHaveTheCorrectMimeType()
     {
+        if (!function_exists('finfo')) {
+            $this->markTestSkipped('finfo is not available on this system (possibly running on Windows where the DLL needs to be added explicitly to the php.ini)');
+        }
+
         $fileName = 'test_mime_type.xlsx';
         $resourcePath = $this->getGeneratedResourcePath($fileName);
         $dataRows = $this->createRowsFromValues([['foo']]);