feat: add diagnostic interview loop

internal/httpapi/diagnostic_test.go

@@ -0,0 +1,76 @@
+package httpapi
+
+import (
+	"bytes"
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"tutor/internal/config"
+	"tutor/internal/interview"
+	"tutor/internal/workflows"
+)
+
+func TestDiagnosticHTTPFlow(t *testing.T) {
+	service := interview.NewService(interview.NewMemoryStore(), workflows.NewStubRunner())
+	handler := NewHandler(config.Config{Environment: "test", ModelKey: "deepseek-v4-flash"}, service)
+	routes := handler.Routes()
+
+	createBody := bytes.NewBufferString(`{
+		"user_id":"user-1",
+		"target_role":"junior backend developer",
+		"stack":["go","postgres"],
+		"interview_timeline":"30 days"
+	}`)
+	createReq := httptest.NewRequest(http.MethodPost, "/api/v1/diagnostic-sessions", createBody)
+	createRec := httptest.NewRecorder()
+	routes.ServeHTTP(createRec, createReq)
+
+	if createRec.Code != http.StatusCreated {
+		t.Fatalf("create status = %d, body = %s", createRec.Code, createRec.Body.String())
+	}
+
+	var session interview.Session
+	if err := json.NewDecoder(createRec.Body).Decode(&session); err != nil {
+		t.Fatalf("decode create response: %v", err)
+	}
+	if len(session.Questions) == 0 {
+		t.Fatal("expected questions")
+	}
+
+	answerBody := bytes.NewBufferString(`{
+		"question_id":"` + session.Questions[0].ID + `",
+		"answer_text":"Idempotent requests can be retried safely because repeated calls have the same intended effect."
+	}`)
+	answerReq := httptest.NewRequest(http.MethodPost, "/api/v1/diagnostic-sessions/"+session.ID+"/answers", answerBody)
+	answerRec := httptest.NewRecorder()
+	routes.ServeHTTP(answerRec, answerReq)
+
+	if answerRec.Code != http.StatusCreated {
+		t.Fatalf("answer status = %d, body = %s", answerRec.Code, answerRec.Body.String())
+	}
+
+	var answer interview.Answer
+	if err := json.NewDecoder(answerRec.Body).Decode(&answer); err != nil {
+		t.Fatalf("decode answer response: %v", err)
+	}
+	if len(answer.Grade.Evidence) == 0 {
+		t.Fatal("expected grade evidence")
+	}
+
+	getReq := httptest.NewRequest(http.MethodGet, "/api/v1/diagnostic-sessions/"+session.ID, nil)
+	getRec := httptest.NewRecorder()
+	routes.ServeHTTP(getRec, getReq)
+
+	if getRec.Code != http.StatusOK {
+		t.Fatalf("get status = %d, body = %s", getRec.Code, getRec.Body.String())
+	}
+	var loaded interview.Session
+	if err := json.NewDecoder(getRec.Body).Decode(&loaded); err != nil {
+		t.Fatalf("decode get response: %v", err)
+	}
+	if len(loaded.Answers) != 1 {
+		t.Fatalf("answers = %d, want 1", len(loaded.Answers))
+	}
+}