diff --git a/codeception.yml b/codeception.yml
new file mode 100644
index 0000000..405575a
--- /dev/null
+++ b/codeception.yml
@@ -0,0 +1,11 @@
+namespace: Psalm\PhpUnitPlugin\Tests
+paths:
+    tests: tests
+    output: tests/_output
+    data: tests/_data
+    support: tests/_support
+    envs: tests/_envs
+actor_suffix: Tester
+extensions:
+    enabled:
+        - Codeception\Extension\RunFailed
diff --git a/composer.json b/composer.json
index 2711931..d20be8e 100755
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,9 @@
         "vimeo/psalm": "^3.0 || dev-master"
     },
     "require-dev": {
-        "squizlabs/php_codesniffer": "^3.3.1"
+        "squizlabs/php_codesniffer": "^3.3.1",
+        "codeception/base": "^2.5",
+        "weirdan/codeception-psalm-module": "dev-master"
     },
     "extra": {
         "psalm": {
@@ -26,13 +28,20 @@
             "Psalm\\PhpUnitPlugin\\": ["."]
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "Psalm\\PhpUnitPlugin\\Tests\\": ["tests/_support"]
+        }
+    },
     "scripts" : {
         "check": [
             "@cs-check",
-            "@analyze"
+            "@analyze",
+	    "@test"
         ],
         "analyze": "psalm",
         "cs-check": "phpcs",
-        "cs-fix": "phpcbf"
+        "cs-fix": "phpcbf",
+	"test": "codecept run -v"
     }
 }
diff --git a/psalm.xml.dist b/psalm.xml.dist
index fa52336..ea3eb4a 100755
--- a/psalm.xml.dist
+++ b/psalm.xml.dist
@@ -9,13 +9,16 @@
         <directory name="." />
         <ignoreFiles>
             <directory name="vendor" />
-	    <directory name="stubs" />
+            <directory name="stubs" />
+            <directory name="tests/_support/_generated" />
         </ignoreFiles>
     </projectFiles>
 
     <issueHandlers>
-
         <LessSpecificReturnType errorLevel="info" />
-
     </issueHandlers>
+
+    <plugins>
+        <pluginClass class="Psalm\PhpUnitPlugin\Plugin"/>
+    </plugins>
 </psalm>
diff --git a/tests/_data/.gitkeep b/tests/_data/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/tests/_output/.gitignore b/tests/_output/.gitignore
new file mode 100644
index 0000000..c96a04f
--- /dev/null
+++ b/tests/_output/.gitignore
@@ -0,0 +1,2 @@
+*
+!.gitignore
\ No newline at end of file
diff --git a/tests/_run/.gitignore b/tests/_run/.gitignore
new file mode 100644
index 0000000..d6b7ef3
--- /dev/null
+++ b/tests/_run/.gitignore
@@ -0,0 +1,2 @@
+*
+!.gitignore
diff --git a/tests/_support/AcceptanceTester.php b/tests/_support/AcceptanceTester.php
new file mode 100644
index 0000000..abbab72
--- /dev/null
+++ b/tests/_support/AcceptanceTester.php
@@ -0,0 +1,26 @@
+<?php
+namespace Psalm\PhpUnitPlugin\Tests;
+
+/**
+ * Inherited Methods
+ * @method void wantToTest($text)
+ * @method void wantTo($text)
+ * @method void execute($callable)
+ * @method void expectTo($prediction)
+ * @method void expect($prediction)
+ * @method void amGoingTo($argumentation)
+ * @method void am($role)
+ * @method void lookForwardTo($achieveValue)
+ * @method void comment($description)
+ * @method \Codeception\Lib\Friend haveFriend($name, $actorClass = NULL)
+ *
+ * @SuppressWarnings(PHPMD)
+*/
+class AcceptanceTester extends \Codeception\Actor
+{
+    use _generated\AcceptanceTesterActions;
+
+   /**
+    * Define custom actions here
+    */
+}
diff --git a/tests/_support/Helper/Acceptance.php b/tests/_support/Helper/Acceptance.php
new file mode 100644
index 0000000..a73bd3b
--- /dev/null
+++ b/tests/_support/Helper/Acceptance.php
@@ -0,0 +1,10 @@
+<?php
+namespace Psalm\PhpUnitPlugin\Tests\Helper;
+
+// here you can define custom actions
+// all public methods declared in helper class will be available in $I
+
+class Acceptance extends \Codeception\Module
+{
+
+}
diff --git a/tests/_support/_generated/.gitignore b/tests/_support/_generated/.gitignore
new file mode 100644
index 0000000..c96a04f
--- /dev/null
+++ b/tests/_support/_generated/.gitignore
@@ -0,0 +1,2 @@
+*
+!.gitignore
\ No newline at end of file
diff --git a/tests/acceptance.suite.yml b/tests/acceptance.suite.yml
new file mode 100644
index 0000000..121c95c
--- /dev/null
+++ b/tests/acceptance.suite.yml
@@ -0,0 +1,7 @@
+actor: AcceptanceTester
+modules:
+    enabled:
+        - Cli
+        - Filesystem
+        - \Weirdan\Codeception\Psalm\Module
+        - \Psalm\PhpUnitPlugin\Tests\Helper\Acceptance
diff --git a/tests/acceptance/Assert.feature b/tests/acceptance/Assert.feature
new file mode 100644
index 0000000..f75ecf6
--- /dev/null
+++ b/tests/acceptance/Assert.feature
@@ -0,0 +1,28 @@
+Feature: Assert
+  In order to use PHPUnit safely
+  As a Psalm user
+  I need Psalm to typecheck asserts
+
+  Background:
+    Given I have the following code preamble
+      """
+      <?php
+      namespace NS;
+      use PHPUnit\Framework\Assert;
+
+      """
+
+  Scenario: Asserting instanceof
+    Given I have the following code
+      """
+      function f(): \Exception {
+        return rand(0,1) ? new \RuntimeException : new \InvalidArgumentException;
+      }
+      function acceptsRuntimeException(\RuntimeException $_e): void {}
+
+      $e = f();
+      Assert::assertInstanceOf(\RuntimeException::class, $e);
+      acceptsRuntimeException($e);
+      """
+    When I run Psalm
+    Then I see no errors