diff --git a/tests/Unit/ActivityTest.php b/tests/Unit/ActivityTest.php
index e0ffd3eb..f4a63e2e 100644
--- a/tests/Unit/ActivityTest.php
+++ b/tests/Unit/ActivityTest.php
@@ -6,11 +6,13 @@
 
 use BadMethodCallException;
 use Exception;
+use Tests\Fixtures\NonRetryableTestExceptionActivity;
 use Tests\Fixtures\TestExceptionActivity;
 use Tests\Fixtures\TestInvalidActivity;
 use Tests\Fixtures\TestOtherActivity;
 use Tests\Fixtures\TestWorkflow;
 use Tests\TestCase;
+use Workflow\Exceptions\NonRetryableException;
 use Workflow\Models\StoredWorkflow;
 use Workflow\Serializers\Serializer;
 use Workflow\States\WorkflowCreatedStatus;
@@ -64,6 +66,24 @@ public function testExceptionActivity(): void
         $this->assertSame(WorkflowFailedStatus::class, $workflow->status());
     }
 
+    public function testNonRetryableExceptionActivity(): void
+    {
+        $this->expectException(NonRetryableException::class);
+
+        $workflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $activity = new NonRetryableTestExceptionActivity(0, now()->toDateTimeString(), StoredWorkflow::findOrFail(
+            $workflow->id()
+        ));
+
+        $activity->handle();
+
+        $workflow->fresh();
+
+        $this->assertSame(1, $workflow->exceptions()->count());
+        $this->assertSame(0, $workflow->logs()->count());
+        $this->assertSame(WorkflowFailedStatus::class, $workflow->status());
+    }
+
     public function testFailedActivity(): void
     {
         $workflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
diff --git a/tests/Unit/ExceptionTest.php b/tests/Unit/ExceptionTest.php
new file mode 100644
index 00000000..dac9eefd
--- /dev/null
+++ b/tests/Unit/ExceptionTest.php
@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit;
+
+use Tests\Fixtures\TestWorkflow;
+use Tests\TestCase;
+use Workflow\Exception;
+use Workflow\Middleware\WithoutOverlappingMiddleware;
+use Workflow\Models\StoredWorkflow;
+use Workflow\Serializers\Serializer;
+use Workflow\States\WorkflowRunningStatus;
+use Workflow\WorkflowStub;
+
+final class ExceptionTest extends TestCase
+{
+    public function testMiddleware(): void
+    {
+        $exception = new Exception(0, now()->toDateTimeString(), new StoredWorkflow(), new \Exception(
+            'Test exception'
+        ));
+
+        $middleware = collect($exception->middleware())
+            ->map(static fn ($middleware) => is_object($middleware) ? get_class($middleware) : $middleware)
+            ->values();
+
+        $this->assertCount(1, $middleware);
+        $this->assertSame([WithoutOverlappingMiddleware::class], $middleware->all());
+    }
+
+    public function testExceptionWorkflowRunning(): void
+    {
+        $workflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedWorkflow = StoredWorkflow::findOrFail($workflow->id());
+        $storedWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowRunningStatus::$name,
+        ]);
+
+        $exception = new Exception(0, now()->toDateTimeString(), $storedWorkflow, new \Exception('Test exception'));
+        $exception->handle();
+
+        $this->assertSame(WorkflowRunningStatus::class, $workflow->status());
+    }
+}
diff --git a/tests/Unit/SignalTest.php b/tests/Unit/SignalTest.php
new file mode 100644
index 00000000..6470acc9
--- /dev/null
+++ b/tests/Unit/SignalTest.php
@@ -0,0 +1,44 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Tests\Unit;
+
+use Tests\Fixtures\TestWorkflow;
+use Tests\TestCase;
+use Workflow\Middleware\WithoutOverlappingMiddleware;
+use Workflow\Models\StoredWorkflow;
+use Workflow\Serializers\Serializer;
+use Workflow\Signal;
+use Workflow\States\WorkflowRunningStatus;
+use Workflow\WorkflowStub;
+
+final class SignalTest extends TestCase
+{
+    public function testMiddleware(): void
+    {
+        $signal = new Signal(new StoredWorkflow());
+
+        $middleware = collect($signal->middleware())
+            ->map(static fn ($middleware) => is_object($middleware) ? get_class($middleware) : $middleware)
+            ->values();
+
+        $this->assertCount(1, $middleware);
+        $this->assertSame([WithoutOverlappingMiddleware::class], $middleware->all());
+    }
+
+    public function testSignalWorkflowRunning(): void
+    {
+        $workflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedWorkflow = StoredWorkflow::findOrFail($workflow->id());
+        $storedWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowRunningStatus::$name,
+        ]);
+
+        $signal = new Signal($storedWorkflow);
+        $signal->handle();
+
+        $this->assertSame(WorkflowRunningStatus::class, $workflow->status());
+    }
+}
diff --git a/tests/Unit/WorkflowTest.php b/tests/Unit/WorkflowTest.php
index 08eeaced..04d09982 100644
--- a/tests/Unit/WorkflowTest.php
+++ b/tests/Unit/WorkflowTest.php
@@ -5,21 +5,129 @@
 namespace Tests\Unit;
 
 use Illuminate\Support\Carbon;
+use Illuminate\Support\Facades\Event;
 use Tests\Fixtures\TestActivity;
 use Tests\Fixtures\TestChildWorkflow;
 use Tests\Fixtures\TestOtherActivity;
 use Tests\Fixtures\TestParentWorkflow;
 use Tests\Fixtures\TestWorkflow;
 use Tests\TestCase;
+use Workflow\Events\WorkflowFailed;
 use Workflow\Exception;
 use Workflow\Models\StoredWorkflow;
 use Workflow\Serializers\Serializer;
 use Workflow\States\WorkflowCompletedStatus;
+use Workflow\States\WorkflowFailedStatus;
 use Workflow\States\WorkflowPendingStatus;
+use Workflow\Workflow;
 use Workflow\WorkflowStub;
 
 final class WorkflowTest extends TestCase
 {
+    public function testFailed(): void
+    {
+        Event::fake();
+
+        $parentWorkflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedParentWorkflow = StoredWorkflow::findOrFail($parentWorkflow->id());
+        $storedParentWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowPendingStatus::$name,
+        ]);
+
+        $stub = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedWorkflow = StoredWorkflow::findOrFail($stub->id());
+        $storedWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowPendingStatus::class,
+        ]);
+
+        $storedWorkflow->parents()
+            ->attach($storedParentWorkflow, [
+                'parent_index' => 0,
+                'parent_now' => now(),
+            ]);
+
+        $workflow = new Workflow($storedWorkflow);
+
+        $workflow->failed(new \Exception('Test exception'));
+
+        $this->assertSame(WorkflowFailedStatus::class, $stub->status());
+        $this->assertSame(
+            'Test exception',
+            Serializer::unserialize($stub->exceptions()->first()->exception)['message']
+        );
+
+        Event::assertDispatched(WorkflowFailed::class, static function ($event) use ($stub) {
+            return $event->workflowId === $stub->id();
+        });
+    }
+
+    public function testFailedTwice(): void
+    {
+        Event::fake();
+
+        $stub = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedWorkflow = StoredWorkflow::findOrFail($stub->id());
+        $storedWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowFailedStatus::class,
+        ]);
+
+        $workflow = new Workflow($storedWorkflow);
+
+        $workflow->failed(new \Exception('Test exception'));
+
+        $this->assertSame(WorkflowFailedStatus::class, $stub->status());
+        $this->assertSame(
+            'Test exception',
+            Serializer::unserialize($stub->exceptions()->first()->exception)['message']
+        );
+
+        Event::assertNotDispatched(WorkflowFailed::class, static function ($event) use ($stub) {
+            return $event->workflowId === $stub->id();
+        });
+    }
+
+    public function testFailedWithParentFailed(): void
+    {
+        Event::fake();
+
+        $parentWorkflow = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedParentWorkflow = StoredWorkflow::findOrFail($parentWorkflow->id());
+        $storedParentWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowFailedStatus::$name,
+        ]);
+
+        $stub = WorkflowStub::load(WorkflowStub::make(TestWorkflow::class)->id());
+        $storedWorkflow = StoredWorkflow::findOrFail($stub->id());
+        $storedWorkflow->update([
+            'arguments' => Serializer::serialize([]),
+            'status' => WorkflowPendingStatus::class,
+        ]);
+
+        $storedWorkflow->parents()
+            ->attach($storedParentWorkflow, [
+                'parent_index' => 0,
+                'parent_now' => now(),
+            ]);
+
+        $workflow = new Workflow($storedWorkflow);
+
+        $workflow->failed(new \Exception('Test exception'));
+
+        $this->assertSame(WorkflowFailedStatus::class, $stub->status());
+        $this->assertSame(
+            'Test exception',
+            Serializer::unserialize($stub->exceptions()->first()->exception)['message']
+        );
+
+        Event::assertDispatched(WorkflowFailed::class, static function ($event) use ($stub) {
+            return $event->workflowId === $stub->id();
+        });
+    }
+
     public function testException(): void
     {
         $exception = new \Exception('test');