Phase 1: database schema, migrations, repository, user seeding

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

internal/db/db_test.go

@@ -0,0 +1,72 @@
+package db_test
+
+import (
+	"os"
+	"path/filepath"
+	"testing"
+
+	"qbank/internal/config"
+	"qbank/internal/db"
+)
+
+func TestOpenAndSeed(t *testing.T) {
+	dir := t.TempDir()
+	dbPath := filepath.Join(dir, "test.db")
+
+	database, err := db.Open(dbPath)
+	if err != nil {
+		t.Fatalf("Open: %v", err)
+	}
+	defer database.Close()
+
+	// All tables must exist.
+	tables := []string{"users", "questions", "answers", "tests", "test_answers", "user_question_stats"}
+	for _, table := range tables {
+		var name string
+		err := database.QueryRow(
+			"SELECT name FROM sqlite_master WHERE type='table' AND name=?", table,
+		).Scan(&name)
+		if err != nil {
+			t.Errorf("table %q missing: %v", table, err)
+		}
+	}
+
+	// Seed two users.
+	users := []config.AdminUser{
+		{Name: "alice", Password: "pass1"},
+		{Name: "bob", Password: "pass2"},
+	}
+	if err := db.Seed(database, users); err != nil {
+		t.Fatalf("Seed: %v", err)
+	}
+
+	var count int
+	database.QueryRow("SELECT COUNT(*) FROM users").Scan(&count)
+	if count != 2 {
+		t.Errorf("want 2 users, got %d", count)
+	}
+
+	// Second Seed call must be a no-op (users table non-empty).
+	if err := db.Seed(database, users); err != nil {
+		t.Fatalf("second Seed: %v", err)
+	}
+	database.QueryRow("SELECT COUNT(*) FROM users").Scan(&count)
+	if count != 2 {
+		t.Errorf("after second seed: want 2 users, got %d", count)
+	}
+
+	// GetUserByName must find alice.
+	repo := db.New(database)
+	u, err := repo.GetUserByName("alice")
+	if err != nil {
+		t.Fatalf("GetUserByName: %v", err)
+	}
+	if u.Name != "alice" {
+		t.Errorf("want alice, got %q", u.Name)
+	}
+	if u.PasswordHash == "" {
+		t.Error("password hash is empty")
+	}
+
+	_ = os.Remove(dbPath)
+}