diff --git a/phpstan.neon b/phpstan.neon
index 241a8dbb..1fcd78e5 100644
--- a/phpstan.neon
+++ b/phpstan.neon
@@ -4,7 +4,6 @@ parameters:
   paths:
     - ./src/
   ignoreErrors:
-    - '#Constant .* not found#'
     - '#Unsafe usage of new static#'
     - '#class Fiber#'
     - '#Attribute class JetBrains\\PhpStorm\\ArrayShape does not exist#'
@@ -15,4 +14,4 @@ parameters:
       analyseAndScan:
             - ./src/globals/ext-tests/swoole.php
             - ./src/globals/ext-tests/swoole.phpt
-            - ./src/globals/test-extensions.php
\ No newline at end of file
+            - ./src/globals/test-extensions.php
diff --git a/phpunit.xml.dist b/phpunit.xml.dist
new file mode 100644
index 00000000..9b045629
--- /dev/null
+++ b/phpunit.xml.dist
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="UTF-8" ?>
+<phpunit
+        bootstrap="tests/bootstrap.php"
+>
+</phpunit>
\ No newline at end of file
diff --git a/tests/SPC/builder/BuilderProviderTest.php b/tests/SPC/builder/BuilderProviderTest.php
new file mode 100644
index 00000000..52a0d35d
--- /dev/null
+++ b/tests/SPC/builder/BuilderProviderTest.php
@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SPC\Tests\builder;
+
+use PHPUnit\Framework\TestCase;
+use SPC\builder\BuilderBase;
+use SPC\builder\BuilderProvider;
+use Symfony\Component\Console\Input\ArgvInput;
+
+/**
+ * @internal
+ */
+class BuilderProviderTest extends TestCase
+{
+    public static function setUpBeforeClass(): void
+    {
+        BuilderProvider::makeBuilderByInput(new ArgvInput());
+        BuilderProvider::getBuilder();
+    }
+
+    public function testMakeBuilderByInput(): void
+    {
+        $this->assertInstanceOf(BuilderBase::class, BuilderProvider::makeBuilderByInput(new ArgvInput()));
+        $this->assertInstanceOf(BuilderBase::class, BuilderProvider::getBuilder());
+    }
+}
diff --git a/tests/SPC/builder/ExtensionTest.php b/tests/SPC/builder/ExtensionTest.php
new file mode 100644
index 00000000..d618980d
--- /dev/null
+++ b/tests/SPC/builder/ExtensionTest.php
@@ -0,0 +1,91 @@
+<?php
+
+declare(strict_types=1);
+
+namespace SPC\Tests\builder;
+
+use PHPUnit\Framework\TestCase;
+use SPC\builder\BuilderProvider;
+use SPC\builder\Extension;
+use SPC\util\DependencyUtil;
+use Symfony\Component\Console\Input\ArgvInput;
+
+/**
+ * @internal
+ */
+class ExtensionTest extends TestCase
+{
+    private Extension $extension;
+
+    protected function setUp(): void
+    {
+        $builder = BuilderProvider::makeBuilderByInput(new ArgvInput());
+        [$extensions, $libs] = DependencyUtil::getExtsAndLibs(['mbregex']);
+        $builder->proveLibs($libs);
+        $builder->proveExts($extensions);
+        $this->extension = $builder->getExt('mbregex');
+    }
+
+    public function testPatches()
+    {
+        $this->assertFalse($this->extension->patchBeforeBuildconf());
+        $this->assertFalse($this->extension->patchBeforeConfigure());
+        $this->assertFalse($this->extension->patchBeforeMake());
+    }
+
+    public function testGetExtensionDependency()
+    {
+        $this->assertEquals('mbstring', current($this->extension->getExtensionDependency())->getName());
+    }
+
+    public function testGetWindowsConfigureArg()
+    {
+        $this->assertEquals('', $this->extension->getWindowsConfigureArg());
+    }
+
+    public function testGetConfigureArg()
+    {
+        $this->assertEquals('', $this->extension->getUnixConfigureArg());
+    }
+
+    public function testGetExtVersion()
+    {
+        // only swoole has version, we cannot test it
+        $this->assertEquals(null, $this->extension->getExtVersion());
+    }
+
+    public function testGetDistName()
+    {
+        $this->assertEquals('mbregex', $this->extension->getName());
+    }
+
+    public function testRunCliCheckWindows()
+    {
+        if (is_unix()) {
+            $this->markTestIncomplete('This test is for Windows only');
+        } else {
+            $this->extension->runCliCheckWindows();
+            $this->assertTrue(true);
+        }
+    }
+
+    public function testGetLibFilesString()
+    {
+        $this->assertStringEndsWith('libonig.a', $this->extension->getLibFilesString());
+    }
+
+    public function testGetName()
+    {
+        $this->assertEquals('mbregex', $this->extension->getName());
+    }
+
+    public function testGetUnixConfigureArg()
+    {
+        $this->assertEquals('', $this->extension->getUnixConfigureArg());
+    }
+
+    public function testGetEnableArg()
+    {
+        $this->assertEquals('', $this->extension->getEnableArg());
+    }
+}
diff --git a/tests/bootstrap.php b/tests/bootstrap.php
new file mode 100644
index 00000000..bca0084d
--- /dev/null
+++ b/tests/bootstrap.php
@@ -0,0 +1,5 @@
+<?php
+
+declare(strict_types=1);
+
+require_once __DIR__ . '/../src/globals/internal-env.php';