Add mutation testing

.gitattributes

@@ -4,6 +4,7 @@
 /composer-require-checker.json export-ignore
 /box.json.dist export-ignore
 /Makefile export-ignore
+/infection.json.dist export-ignore
 /phpcs.xml.dist export-ignore
 /phpstan.neon.dist export-ignore
 /phpunit.xml.dist export-ignore

.github/workflows/integrate.yaml

@@ -152,8 +152,8 @@ jobs:
         run: "composer update --no-interaction --no-progress --ignore-platform-reqs"
 
       - name: "Run tests"
-        timeout-minutes: 10
-        run: "vendor/bin/phpunit"
+        timeout-minutes: 3
+        run: "vendor/bin/phpunit --no-coverage --no-logging"
 
   code-coverage:
     name: "Code Coverage"
@@ -174,6 +174,7 @@ jobs:
         with:
           coverage: "pcov"
           php-version: "${{ matrix.php-version }}"
+          ini-values: zend.assertions=1
           tools: composer:v1
 
       - name: "Get composer cache directory"
@@ -191,13 +192,24 @@ jobs:
         run: "composer update --no-interaction --no-progress"
 
       - name: "Run tests"
-        timeout-minutes: 10
-        run: "vendor/bin/phpunit --coverage-clover=coverage.xml"
+        timeout-minutes: 3
+        run: "vendor/bin/phpunit --coverage-clover=coverage.xml --coverage-xml=coverage/coverage-xml --log-junit=coverage/junit.xml"
 
       - name: "Send code coverage report to Codecov.io"
         uses: codecov/codecov-action@v1
         with:
           token: ${{ secrets.CODECOV_TOKEN }}
+          file: ./coverage.xml
+          fail_ci_if_error: true
+
+      - name: "Infection"
+        timeout-minutes: 10
+        run: "vendor/bin/infection --ansi --threads=$(nproc) --coverage=coverage --skip-initial-tests"
+        env:
+          INFECTION_BADGE_API_KEY: ${{ secrets.INFECTION_BADGE_API_KEY }}
+
+      - name: "Output infections"
+        run: "cat infections.log"
 
   coding-standards:
     name: "Coding Standards"

.gitignore

@@ -1,6 +1,8 @@
 /.idea
+/coverage
 /test/fixtures/generated_tests
 /vendor
 composer.lock
 .phpunit.result.cache
 .php_cs.cache
+infections.log

Makefile

@@ -17,4 +17,8 @@ static-analysis: vendor
 
 .PHONY: test
 test: vendor
-	php -d zend.assertions=1 vendor/bin/phpunit ${arg}
+	php -d zend.assertions=1 vendor/bin/phpunit --coverage-xml=coverage/coverage-xml --log-junit=coverage/junit.xml
+
+.PHONY: code-coverage
+code-coverage: test
+	php -d zend.assertions=1 vendor/bin/infection --threads=$(shell nproc) --coverage=coverage --skip-initial-tests

README.md

@@ -6,6 +6,7 @@ ParaTest
 [![Integrate](https://github.com/paratestphp/paratest/workflows/Integrate/badge.svg?branch=master)](https://github.com/paratestphp/paratest/actions)
 [![Code Coverage](https://codecov.io/gh/paratestphp/paratest/coverage.svg?branch=master)](https://codecov.io/gh/paratestphp/paratest?branch=master)
 [![Type Coverage](https://shepherd.dev/github/paratestphp/paratest/coverage.svg)](https://shepherd.dev/github/paratestphp/paratest)
+[![Infection MSI](https://badge.stryker-mutator.io/github.com/paratestphp/paratest/master)](https://dashboard.stryker-mutator.io/reports/github.com/paratestphp/paratest/master)
 
 The objective of ParaTest is to support parallel testing in PHPUnit. Provided you have well-written PHPUnit tests, you can drop `paratest` in your project and
 start using it with no additional bootstrap or configurations!

composer.json

@@ -36,6 +36,7 @@
         "doctrine/coding-standard": "^8.1.0",
         "ekino/phpstan-banned-code": "^0.3.1",
         "ergebnis/phpstan-rules": "^0.15.2",
+        "infection/infection": "^0.17.3",
         "phpstan/phpstan": "^0.12.42",
         "phpstan/phpstan-deprecation-rules": "^0.12.5",
         "phpstan/phpstan-phpunit": "^0.12.16",

infection.json.dist

@@ -0,0 +1,19 @@
+{
+    "source": {
+        "directories": [
+            "src"
+        ]
+    },
+    "timeout": 10,
+    "logs": {
+        "text": "infections.log",
+        "badge": {
+            "branch": "master"
+        }
+    },
+    "mutators": {
+        "@default": true
+    },
+    "minMsi": 82,
+    "minCoveredMsi": 84
+}

phpunit.xml.dist

@@ -14,6 +14,9 @@
     <include>
       <directory suffix=".php">src</directory>
     </include>
+    <report>
+      <text outputFile="php://stdout" showUncoveredFiles="false" showOnlySummary="true"/>
+    </report>
   </coverage>
   <testsuites>
     <testsuite name="ParaTest Unit Tests">