Phase 3: PDF/DOCX extraction, chunking, LLM client with mock interface

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/llm/openai_test.go

@@ -0,0 +1,129 @@
+package llm_test
+
+import (
+	"context"
+	"encoding/json"
+	"testing"
+
+	openai "github.com/sashabaranov/go-openai"
+
+	"qbank/internal/llm"
+)
+
+// mockChat implements llm.ChatClient for testing.
+type mockChat struct{ body string }
+
+func (m *mockChat) CreateChatCompletion(_ context.Context, _ openai.ChatCompletionRequest) (openai.ChatCompletionResponse, error) {
+	return openai.ChatCompletionResponse{
+		Choices: []openai.ChatCompletionChoice{
+			{Message: openai.ChatCompletionMessage{Content: m.body}},
+		},
+	}, nil
+}
+
+func mockClient(t *testing.T, questions []map[string]any) *llm.Client {
+	t.Helper()
+	body, err := json.Marshal(map[string]any{"questions": questions})
+	if err != nil {
+		t.Fatal(err)
+	}
+	return llm.NewWithClient(&mockChat{body: string(body)}, "test-model")
+}
+
+func TestExtractQuestions_HappyPath(t *testing.T) {
+	qs, err := mockClient(t, []map[string]any{
+		{
+			"question": "What is 2+2?",
+			"answers": []map[string]any{
+				{"text": "3", "correct": false},
+				{"text": "4", "correct": true},
+				{"text": "5", "correct": false},
+			},
+		},
+	}).ExtractQuestions(context.Background(), "text")
+
+	if err != nil {
+		t.Fatalf("ExtractQuestions: %v", err)
+	}
+	if len(qs) != 1 {
+		t.Fatalf("want 1 question, got %d", len(qs))
+	}
+	if qs[0].Question != "What is 2+2?" {
+		t.Errorf("wrong question text: %q", qs[0].Question)
+	}
+	if len(qs[0].Answers) != 3 {
+		t.Errorf("want 3 answers, got %d", len(qs[0].Answers))
+	}
+}
+
+func TestExtractQuestions_DropsInvalid(t *testing.T) {
+	qs, err := mockClient(t, []map[string]any{
+		{
+			"question": "Two correct — should drop",
+			"answers": []map[string]any{
+				{"text": "A", "correct": true},
+				{"text": "B", "correct": true},
+			},
+		},
+		{
+			"question": "Zero correct — should drop",
+			"answers": []map[string]any{
+				{"text": "A", "correct": false},
+				{"text": "B", "correct": false},
+			},
+		},
+		{
+			"question": "Valid question",
+			"answers": []map[string]any{
+				{"text": "Wrong", "correct": false},
+				{"text": "Right", "correct": true},
+			},
+		},
+	}).ExtractQuestions(context.Background(), "text")
+
+	if err != nil {
+		t.Fatalf("ExtractQuestions: %v", err)
+	}
+	if len(qs) != 1 {
+		t.Fatalf("want 1 question after dropping invalid, got %d", len(qs))
+	}
+	if qs[0].Question != "Valid question" {
+		t.Errorf("wrong question kept: %q", qs[0].Question)
+	}
+}
+
+func TestExtractQuestions_Dedup(t *testing.T) {
+	qs, err := mockClient(t, []map[string]any{
+		{
+			"question": "Duplicate?",
+			"answers": []map[string]any{
+				{"text": "Yes", "correct": true},
+				{"text": "No", "correct": false},
+			},
+		},
+		{
+			"question": "Duplicate?",
+			"answers": []map[string]any{
+				{"text": "Yes", "correct": true},
+				{"text": "No", "correct": false},
+			},
+		},
+	}).ExtractQuestions(context.Background(), "text")
+
+	if err != nil {
+		t.Fatalf("ExtractQuestions: %v", err)
+	}
+	if len(qs) != 1 {
+		t.Errorf("want 1 unique question after dedup, got %d", len(qs))
+	}
+}
+
+func TestExtractQuestions_EmptyResponse(t *testing.T) {
+	qs, err := mockClient(t, []map[string]any{}).ExtractQuestions(context.Background(), "text")
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	if len(qs) != 0 {
+		t.Errorf("want 0 questions for empty response, got %d", len(qs))
+	}
+}