diff --git a/README.md b/README.md
index e955e6c..4638ab0 100644
--- a/README.md
+++ b/README.md
@@ -1,2 +1,9 @@
 # Allowance Planner 2000
 An improved Allowance Planner app.
+
+## Running backend
+In order to run the backend, go to the `backend directory and run:
+
+```bash
+$ go run .
+```
diff --git a/backend/api_test.go b/backend/api_test.go
index 68f4708..2fc70a1 100644
--- a/backend/api_test.go
+++ b/backend/api_test.go
@@ -520,6 +520,40 @@ func TestPutAllowanceById(t *testing.T) {
 	result.Value("weight").IsEqual(15)
 }
 
+func TestCompleteTask(t *testing.T) {
+	e := startServer(t)
+	createTestTask(e)
+
+	// Create a task
+	requestBody := map[string]interface{}{
+		"name":   "Test Task",
+		"reward": 100,
+	}
+	e.POST("/tasks").WithJSON(requestBody).Expect().Status(201)
+
+	// Create two allowance goals
+	e.POST("/user/1/allowance").WithJSON(CreateAllowanceRequest{
+		Name:   "Test Allowance 1",
+		Target: 1000,
+		Weight: 50,
+	}).Expect().Status(200)
+	e.POST("/user/1/allowance").WithJSON(CreateAllowanceRequest{
+		Name:   "Test Allowance 1",
+		Target: 1000,
+		Weight: 25,
+	}).Expect().Status(200)
+	e.PUT("/user/1/allowance/0").WithJSON(UpdateAllowanceRequest{
+		Weight: 25,
+	})
+
+	// Complete the task
+	e.POST("/task/1/complete").Expect().Status(200)
+
+	// Verify the task is marked as completed
+	result := e.GET("/task/1").Expect().Status(200).JSON().Object()
+	result.Value("completed").Boolean().IsTrue()
+}
+
 func getDelta(base time.Time, delta float64) (time.Time, time.Time) {
 	start := base.Add(-time.Duration(delta) * time.Second)
 	end := base.Add(time.Duration(delta) * time.Second)