diff --git a/tests/concurrency/concurrency_test.go b/tests/concurrency/concurrency_test.go
new file mode 100644
index 0000000..b20904e
--- /dev/null
+++ b/tests/concurrency/concurrency_test.go
@@ -0,0 +1,173 @@
+package concurrency_test
+
+import (
+	"context"
+	"errors"
+	"testing"
+	"time"
+
+	"github.com/hokamsingh/lessgo/internal/core/concurrency"
+)
+
+type TaskFunc = concurrency.TaskFunc
+
+var Parallel = concurrency.Parallel
+var Sequential = concurrency.Sequential
+var NewTaskBuilder = concurrency.NewTaskBuilder
+
+// Helper function to create a simple task that returns a result after a delay.
+func createDelayedTask(result interface{}, delay time.Duration) TaskFunc {
+	return func(ctx context.Context) (interface{}, error) {
+		select {
+		case <-ctx.Done():
+			return nil, ctx.Err()
+		case <-time.After(delay):
+			return result, nil
+		}
+	}
+}
+
+// Helper function to create a task that returns an error.
+func createErrorTask(err error) TaskFunc {
+	return func(ctx context.Context) (interface{}, error) {
+		return nil, err
+	}
+}
+
+// Test TaskManager for parallel task execution with no errors.
+func TestTaskManager_RunParallel_NoError(t *testing.T) {
+	ctx := context.Background()
+
+	taskBuilder := NewTaskBuilder(Parallel, 5)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createDelayedTask("result2", 200*time.Millisecond)).
+		Add(createDelayedTask("result3", 300*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err != nil {
+		t.Fatalf("Expected no error, but got: %v", err)
+	}
+
+	expectedResults := []interface{}{"result1", "result2", "result3"}
+	for i, result := range results {
+		if result != expectedResults[i] {
+			t.Errorf("Expected result %v, but got %v", expectedResults[i], result)
+		}
+	}
+}
+
+// Test TaskManager for parallel task execution with an error in one task.
+func TestTaskManager_RunParallel_WithError(t *testing.T) {
+	ctx := context.Background()
+
+	taskBuilder := NewTaskBuilder(Parallel, 5)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createErrorTask(errors.New("task error"))).
+		Add(createDelayedTask("result3", 200*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err == nil {
+		t.Fatal("Expected error, but got none")
+	}
+
+	if err.Error() != "task error" {
+		t.Errorf("Expected 'task error', but got %v", err)
+	}
+
+	if results != nil {
+		t.Errorf("Expected results to be nil on error, but got %v", results)
+	}
+}
+
+// Test TaskManager for sequential task execution with no errors.
+func TestTaskManager_RunSequential_NoError(t *testing.T) {
+	ctx := context.Background()
+
+	taskBuilder := NewTaskBuilder(Sequential, 0)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createDelayedTask("result2", 200*time.Millisecond)).
+		Add(createDelayedTask("result3", 300*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err != nil {
+		t.Fatalf("Expected no error, but got: %v", err)
+	}
+
+	expectedResults := []interface{}{"result1", "result2", "result3"}
+	for i, result := range results {
+		if result != expectedResults[i] {
+			t.Errorf("Expected result %v, but got %v", expectedResults[i], result)
+		}
+	}
+}
+
+// Test TaskManager for sequential task execution with an error in one task.
+func TestTaskManager_RunSequential_WithError(t *testing.T) {
+	ctx := context.Background()
+
+	taskBuilder := NewTaskBuilder(Sequential, 0)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createErrorTask(errors.New("task error"))).
+		Add(createDelayedTask("result3", 200*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err == nil {
+		t.Fatal("Expected error, but got none")
+	}
+
+	if err.Error() != "task error" {
+		t.Errorf("Expected 'task error', but got %v", err)
+	}
+
+	if results != nil {
+		t.Errorf("Expected results to be nil on error, but got %v", results)
+	}
+}
+
+// Test for context cancellation in parallel execution.
+func TestTaskManager_RunParallel_ContextCancelled(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 150*time.Millisecond)
+	defer cancel()
+
+	taskBuilder := NewTaskBuilder(Parallel, 5)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createDelayedTask("result2", 200*time.Millisecond)).
+		Add(createDelayedTask("result3", 300*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err == nil {
+		t.Fatal("Expected context canceled error, but got none")
+	}
+
+	if err != context.DeadlineExceeded {
+		t.Errorf("Expected DeadlineExceeded error, but got %v", err)
+	}
+
+	if results != nil {
+		t.Errorf("Expected results to be nil on cancellation, but got %v", results)
+	}
+}
+
+// Test for context cancellation in sequential execution.
+func TestTaskManager_RunSequential_ContextCancelled(t *testing.T) {
+	ctx, cancel := context.WithTimeout(context.Background(), 150*time.Millisecond)
+	defer cancel()
+
+	taskBuilder := NewTaskBuilder(Sequential, 0)
+	taskBuilder.Add(createDelayedTask("result1", 100*time.Millisecond)).
+		Add(createDelayedTask("result2", 200*time.Millisecond)).
+		Add(createDelayedTask("result3", 300*time.Millisecond))
+
+	results, err := taskBuilder.Run(ctx)
+	if err == nil {
+		t.Fatal("Expected context canceled error, but got none")
+	}
+
+	if err != context.DeadlineExceeded {
+		t.Errorf("Expected DeadlineExceeded error, but got %v", err)
+	}
+
+	if results != nil {
+		t.Errorf("Expected results to be nil on cancellation, but got %v", results)
+	}
+}