feat: add diagnostic interview loop

internal/interview/service_test.go

@@ -0,0 +1,87 @@
+package interview
+
+import (
+	"context"
+	"testing"
+
+	"tutor/internal/workflows"
+)
+
+func TestDiagnosticSessionAnswerFlow(t *testing.T) {
+	service := NewService(NewMemoryStore(), workflows.NewStubRunner())
+
+	session, err := service.CreateSession(context.Background(), CreateSessionInput{
+		UserID:     "user-1",
+		TargetRole: "junior backend developer",
+		Stack:      []string{"go", "postgres"},
+	})
+	if err != nil {
+		t.Fatalf("CreateSession error: %v", err)
+	}
+	if session.Track != BackendDeveloperTrack {
+		t.Fatalf("Track = %q", session.Track)
+	}
+	if session.Status != SessionInProgress {
+		t.Fatalf("Status = %q, want %q", session.Status, SessionInProgress)
+	}
+	if len(session.Questions) == 0 {
+		t.Fatal("expected diagnostic questions")
+	}
+
+	answer, err := service.SubmitAnswer(context.Background(), SubmitAnswerInput{
+		SessionID:  session.ID,
+		QuestionID: session.Questions[0].ID,
+		AnswerText: "Idempotent methods can be retried safely because repeated calls have the same intended effect.",
+	})
+	if err != nil {
+		t.Fatalf("SubmitAnswer error: %v", err)
+	}
+	if answer.Grade.AnswerID != answer.ID {
+		t.Fatalf("grade answer id = %q, want %q", answer.Grade.AnswerID, answer.ID)
+	}
+	if len(answer.Grade.Concepts) == 0 {
+		t.Fatal("expected graded concepts")
+	}
+	if len(answer.Grade.Evidence) == 0 {
+		t.Fatal("expected grading evidence")
+	}
+
+	loaded, err := service.GetSession(session.ID)
+	if err != nil {
+		t.Fatalf("GetSession error: %v", err)
+	}
+	if len(loaded.Answers) != 1 {
+		t.Fatalf("answers = %d, want 1", len(loaded.Answers))
+	}
+}
+
+func TestDiagnosticSessionCompletesAfterAllQuestionsAnswered(t *testing.T) {
+	service := NewService(NewMemoryStore(), workflows.NewStubRunner())
+
+	session, err := service.CreateSession(context.Background(), CreateSessionInput{
+		UserID:     "user-1",
+		TargetRole: "junior backend developer",
+		Stack:      []string{"go"},
+	})
+	if err != nil {
+		t.Fatalf("CreateSession error: %v", err)
+	}
+
+	for _, question := range session.Questions {
+		if _, err := service.SubmitAnswer(context.Background(), SubmitAnswerInput{
+			SessionID:  session.ID,
+			QuestionID: question.ID,
+			AnswerText: "This answer gives a concrete backend tradeoff with an operational example for the interview.",
+		}); err != nil {
+			t.Fatalf("SubmitAnswer(%s) error: %v", question.ID, err)
+		}
+	}
+
+	loaded, err := service.GetSession(session.ID)
+	if err != nil {
+		t.Fatalf("GetSession error: %v", err)
+	}
+	if loaded.Status != SessionComplete {
+		t.Fatalf("Status = %q, want %q", loaded.Status, SessionComplete)
+	}
+}