feat(T3.3): implement task dependency graph

- Add internal/graph package for dependency management - Implement DependencyGraph for task ordering - Support task dependencies and prerequisite tracking - Validate graph for cycles (no circular dependencies) - Topological sort for execution order (Kahn's algorithm) - Track task status (pending, completed, failed) - Get ready-to-execute tasks based on dependencies - Get tasks that depend on a given task - Check if task can execute (all deps complete) - Calculate critical path through graph - Task metadata support - 23 graph tests, all passing Features: - AddTask() - add task to graph - AddDependency(dependent, prerequisite) - specify ordering - ValidateGraph() - check for cycles - GetTopologicalOrder() - execution order - GetReadyTasks() - tasks ready to run - MarkCompleted(taskID) - mark as done - MarkFailed(taskID) - mark as failed - GetDependencies(taskID) - what task depends on - GetDependents(taskID) - what depends on task - CanExecuteTask(taskID) - check if ready - GetCriticalPath() - longest path in graph Graph Properties: - Directed acyclic graph (DAG) - Cycle detection (prevents deadlocks) - Multi-dependency support (diamond dependencies) - Status tracking (pending/completed/failed) - Thread-safe (RWMutex) - Kahn's algorithm for topological sort - O(V+E) for validation and sorting Example Usage: - T0.1 Analyze (no deps) - T0.2 Implement (depends on T0.1) - T0.3 Test (depends on T0.2) - T0.4 Review (depends on T0.2, T0.3) Ready Detection: - T0.1 ready (no dependencies) - After T0.1 complete: T0.2 ready - After T0.2 complete: T0.3 ready - After T0.2, T0.3 complete: T0.4 ready Test Coverage: - 23 dependency graph tests - Cycle detection verified - Topological sort tested - Multiple dependency chains - Diamond dependency patterns - Ready task calculation - Status tracking - Critical path calculation - Complex graphs (10+ tasks) - Metadata handling - Performance benchmarks Performance: - Cycle detection: O(V+E) DFS - Topological sort: O(V+E) Kahn's algorithm - Ready tasks: O(V) scan - Add task: O(1) - Add dependency: O(1) amortized Use Cases: - Workflow orchestration (T0.1 -> T0.2 -> T0.3 -> ...) - CI/CD pipelines (build -> test -> deploy) - Milestone hierarchies (T0 milestone with sub-tasks) - Parallel tasks with merge points (diamond deps) Next: T3.4 (Human-in-the-loop gates)
2026-08-23 17:32:55 -07:00
parent b0313ae818
commit e00762bb0b
3 changed files with 777 additions and 1 deletions
@@ -0,0 +1,372 @@
+package graph
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestNewDependencyGraph(t *testing.T) {
+	graph := NewDependencyGraph()
+	assert.NotNil(t, graph)
+	assert.Equal(t, 0, len(graph.GetAllTasks()))
+}
+
+func TestAddTask(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	task := &Task{ID: "T1", Title: "Task 1"}
+	err := graph.AddTask(task)
+
+	assert.NoError(t, err)
+	retrieved, exists := graph.GetTask("T1")
+	assert.True(t, exists)
+	assert.Equal(t, "T1", retrieved.ID)
+}
+
+func TestAddTaskNil(t *testing.T) {
+	graph := NewDependencyGraph()
+	err := graph.AddTask(nil)
+	assert.Error(t, err)
+}
+
+func TestAddTaskDuplicate(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	task := &Task{ID: "T1", Title: "Task 1"}
+	graph.AddTask(task)
+
+	err := graph.AddTask(task)
+	assert.Error(t, err)
+}
+
+func TestAddDependency(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+
+	err := graph.AddDependency("T2", "T1")
+	assert.NoError(t, err)
+
+	deps, _ := graph.GetDependencies("T2")
+	assert.Equal(t, 1, len(deps))
+	assert.Equal(t, "T1", deps[0])
+}
+
+func TestAddDependencyNotFound(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+
+	err := graph.AddDependency("T2", "T1")
+	assert.Error(t, err)
+}
+
+func TestValidateGraphNoCycles(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T2")
+
+	err := graph.ValidateGraph()
+	assert.NoError(t, err)
+}
+
+func TestValidateGraphWithCycle(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T2")
+	graph.AddDependency("T1", "T3") // Creates cycle
+
+	err := graph.ValidateGraph()
+	assert.Error(t, err)
+}
+
+func TestGetTopologicalOrder(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T2")
+
+	graph.ValidateGraph()
+	order, err := graph.GetTopologicalOrder()
+
+	assert.NoError(t, err)
+	assert.Equal(t, 3, len(order))
+	assert.Equal(t, "T1", order[0])
+	assert.Equal(t, "T2", order[1])
+	assert.Equal(t, "T3", order[2])
+}
+
+func TestGetReadyTasks(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T1")
+
+	ready := graph.GetReadyTasks()
+	assert.Equal(t, 1, len(ready))
+	assert.Equal(t, "T1", ready[0])
+
+	graph.MarkCompleted("T1")
+	ready = graph.GetReadyTasks()
+	assert.Equal(t, 2, len(ready))
+}
+
+func TestMarkCompleted(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	err := graph.MarkCompleted("T1")
+
+	assert.NoError(t, err)
+	status, _ := graph.GetTaskStatus("T1")
+	assert.Equal(t, "completed", status)
+}
+
+func TestMarkFailed(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	err := graph.MarkFailed("T1")
+
+	assert.NoError(t, err)
+	status, _ := graph.GetTaskStatus("T1")
+	assert.Equal(t, "failed", status)
+}
+
+func TestGetDependencies(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T3", "T1")
+	graph.AddDependency("T3", "T2")
+
+	deps, _ := graph.GetDependencies("T3")
+	assert.Equal(t, 2, len(deps))
+}
+
+func TestGetDependents(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+	graph.AddTask(&Task{ID: "T3", Title: "Task 3"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T1")
+
+	dependents, _ := graph.GetDependents("T1")
+	assert.Equal(t, 2, len(dependents))
+}
+
+func TestCanExecuteTask(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+
+	graph.AddDependency("T2", "T1")
+
+	assert.False(t, graph.CanExecuteTask("T2"))
+
+	graph.MarkCompleted("T1")
+	assert.True(t, graph.CanExecuteTask("T2"))
+}
+
+func TestGetGraphStats(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	graph.AddTask(&Task{ID: "T2", Title: "Task 2"})
+
+	graph.MarkCompleted("T1")
+
+	stats := graph.GetGraphStats()
+	assert.Equal(t, 2, stats["total_tasks"])
+	assert.Equal(t, 1, stats["completed_tasks"])
+	assert.Equal(t, 1, stats["pending_tasks"])
+}
+
+func TestClear(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1", Title: "Task 1"})
+	assert.Equal(t, 1, len(graph.GetAllTasks()))
+
+	graph.Clear()
+	assert.Equal(t, 0, len(graph.GetAllTasks()))
+}
+
+func TestMultipleDependencies(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	for i := 1; i <= 5; i++ {
+		id := string(rune(48 + i))
+		graph.AddTask(&Task{ID: "T" + id, Title: "Task " + id})
+	}
+
+	// Chain: T1 -> T2 -> T3 -> T4 -> T5
+	for i := 2; i <= 5; i++ {
+		graph.AddDependency("T"+string(rune(48+i)), "T"+string(rune(48+i-1)))
+	}
+
+	ready := graph.GetReadyTasks()
+	assert.Equal(t, 1, len(ready))
+	assert.Equal(t, "T1", ready[0])
+}
+
+func TestDiamondDependency(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	// Diamond: T1 -> (T2, T3) -> T4
+	graph.AddTask(&Task{ID: "T1"})
+	graph.AddTask(&Task{ID: "T2"})
+	graph.AddTask(&Task{ID: "T3"})
+	graph.AddTask(&Task{ID: "T4"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T1")
+	graph.AddDependency("T4", "T2")
+	graph.AddDependency("T4", "T3")
+
+	graph.ValidateGraph()
+	order, _ := graph.GetTopologicalOrder()
+
+	assert.Equal(t, 4, len(order))
+	assert.Equal(t, "T1", order[0])
+	assert.Equal(t, "T4", order[3])
+}
+
+func TestGetCriticalPath(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	graph.AddTask(&Task{ID: "T1"})
+	graph.AddTask(&Task{ID: "T2"})
+	graph.AddTask(&Task{ID: "T3"})
+	graph.AddTask(&Task{ID: "T4"})
+
+	graph.AddDependency("T2", "T1")
+	graph.AddDependency("T3", "T2")
+	graph.AddDependency("T4", "T3")
+
+	graph.ValidateGraph()
+	graph.GetTopologicalOrder()
+
+	path := graph.GetCriticalPath()
+	assert.Greater(t, len(path), 0)
+	assert.Equal(t, "T1", path[0])
+}
+
+func TestComplexGraph(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	// Create 10 tasks with complex dependencies
+	for i := 1; i <= 10; i++ {
+		id := string(rune(48 + i%10))
+		if i >= 10 {
+			id = "T" + id
+		} else {
+			id = "T0" + id
+		}
+		graph.AddTask(&Task{ID: id})
+	}
+
+	// Add various dependencies
+	graph.AddDependency("T02", "T01")
+	graph.AddDependency("T03", "T01")
+	graph.AddDependency("T04", "T02")
+	graph.AddDependency("T04", "T03")
+
+	graph.ValidateGraph()
+	order, _ := graph.GetTopologicalOrder()
+	assert.Equal(t, 10, len(order))
+}
+
+func TestTaskWithMetadata(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	task := &Task{
+		ID:    "T1",
+		Title: "Task 1",
+		Metadata: map[string]interface{}{
+			"priority": "high",
+			"owner":    "team-a",
+		},
+	}
+
+	graph.AddTask(task)
+	retrieved, _ := graph.GetTask("T1")
+	assert.Equal(t, "high", retrieved.Metadata["priority"])
+}
+
+func TestGetAllTasks(t *testing.T) {
+	graph := NewDependencyGraph()
+
+	for i := 1; i <= 5; i++ {
+		id := string(rune(48 + i))
+		graph.AddTask(&Task{ID: "T" + id})
+	}
+
+	all := graph.GetAllTasks()
+	assert.Equal(t, 5, len(all))
+}
+
+func BenchmarkAddTask(b *testing.B) {
+	graph := NewDependencyGraph()
+
+	for i := 0; i < b.N; i++ {
+		id := string(rune(48 + i%100))
+		graph.AddTask(&Task{ID: "T" + id})
+	}
+}
+
+func BenchmarkAddDependency(b *testing.B) {
+	graph := NewDependencyGraph()
+
+	for i := 0; i < 1000; i++ {
+		graph.AddTask(&Task{ID: "T" + string(rune(48+i%100))})
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		from := "T" + string(rune(48+i%100))
+		to := "T" + string(rune(48+(i+1)%100))
+		graph.AddDependency(from, to)
+	}
+}
+
+func BenchmarkGetReadyTasks(b *testing.B) {
+	graph := NewDependencyGraph()
+
+	for i := 1; i <= 100; i++ {
+		id := "T" + string(rune(48+i%100))
+		graph.AddTask(&Task{ID: id})
+	}
+
+	b.ResetTimer()
+	for i := 0; i < b.N; i++ {
+		graph.GetReadyTasks()
+	}
+}