diff --git a/.gitignore b/.gitignore
index e43b0f9..16231e3 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1,4 @@
 .DS_Store
+/vendor
+/composer.lock
+/.phpunit.result.cache
\ No newline at end of file
diff --git a/composer.json b/composer.json
new file mode 100644
index 0000000..2f05501
--- /dev/null
+++ b/composer.json
@@ -0,0 +1,5 @@
+{
+    "require-dev": {
+        "phpunit/phpunit": "^9.5"
+    }
+}
diff --git a/phpunit.xml b/phpunit.xml
new file mode 100644
index 0000000..97da343
--- /dev/null
+++ b/phpunit.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<phpunit
+    bootstrap="vendor/autoload.php"
+    colors="true"
+    verbose="true"
+    stopOnFailure="false"
+    backupGlobals="false"
+>
+    <testsuites>
+        <testsuite
+            name="testsuite"
+        >
+            <directory>tests</directory>
+        </testsuite>
+    </testsuites>
+    <php>
+        <ini name="display_errors" value="On" />
+        <ini name="display_startup_errors" value="On" />
+    </php>
+</phpunit>
\ No newline at end of file
diff --git a/tests/Test.php b/tests/Test.php
new file mode 100644
index 0000000..16c5a06
--- /dev/null
+++ b/tests/Test.php
@@ -0,0 +1,55 @@
+<?php
+class Test extends \PHPUnit\Framework\TestCase
+{  
+  	protected $blacklist = '';
+
+    protected function setUp(): void
+    {
+        $filename = __DIR__.'/../blacklist.txt';
+        if(file_exists($filename)) {
+            $this->blacklist = file_get_contents($filename);
+        }
+    }
+  
+    public function testFalsePositives()
+    {
+        $this->runTestInFolder('false_positives');
+    }
+
+    public function testFalseNegatives() {
+        $this->runTestInFolder('false_negatives');
+    }
+
+    private function runTestInFolder($folder) {
+        $files = $this->getFilesInFolder($folder);
+        foreach($files as $files__value) {
+            $file_content = file_get_contents(__DIR__ . '/' . $folder . '/' . $files__value);
+            foreach(explode("\n", $file_content) as $file_content__value) {
+                if( $file_content__value == '' ) { continue; }
+                $match = null;
+                foreach(explode("\n", $this->blacklist) as $blacklist__value) {
+                    if( $blacklist__value == '' ) { continue; }
+                    $pattern = sprintf('#%s#i', preg_quote($blacklist__value, '#'));
+                    if( preg_match($pattern, $file_content__value) ) { 
+                        $match = ['blacklist' => $blacklist__value, 'string' => $file_content__value];
+                        break;
+                    }
+                }
+                if( $folder === 'false_positives' && $match !== null ) {
+                    $this->assertEquals('"'.$match['string'].'" => "'.$match['blacklist']. '"', 'FALSELY DETECTED AS SPAM');
+                }
+                else if( $folder === 'false_negatives' && $match === null ) {
+                    $this->assertEquals($file_content__value, 'FALSELY NOT DETECTED AS SPAM');
+                }
+                else {
+                    $this->assertTrue(true);
+                }
+            }
+        }   
+    }
+
+    private function getFilesInFolder($folder) {
+        if( !is_string($folder) || $folder == '' || !is_dir(__DIR__ . '/' . $folder) ) { return []; }
+        return array_diff(scandir(__DIR__ . '/' . $folder), ['.', '..']);
+    }
+}
\ No newline at end of file
diff --git a/tests/false_negatives/2021-09-15.txt b/tests/false_negatives/2021-09-15.txt
new file mode 100644
index 0000000..934ee09
--- /dev/null
+++ b/tests/false_negatives/2021-09-15.txt
@@ -0,0 +1,2 @@
+loli*ta gi*rl fu*ck c*p pt*hc
+I do spy software your website.
diff --git a/tests/false_positives/2021-09-15.txt b/tests/false_positives/2021-09-15.txt
new file mode 100644
index 0000000..54be307
--- /dev/null
+++ b/tests/false_positives/2021-09-15.txt
@@ -0,0 +1,12 @@
+foobar@icloud.com
+foobar@yahoo.com
+foobar@1und1.de
+foobar@ionos.de
+foobar@gmail.com
+foobar@freenet.de
+foobar@aol.com
+foobar@outlook.de
+foobar@t-online.de
+foobar@web.de
+foobar@gmx.de
+foobar@gmx.net