refactor(tests): centralize DB query assertions with helpers

Reduce repetitive raw SQL in test bodies by routing scalar and multi-column checks through shared helpers, keeping test intent clearer without changing behavior.

go-backend/tests/contract/db_test_helper_test.go

@@ -0,0 +1,119 @@
+package contract_test
+
+import (
+	"database/sql"
+	"testing"
+
+	"go-backend/internal/store/repo"
+)
+
+func mustLastInsertID(t *testing.T, r *repo.Repository, label string) int64 {
+	t.Helper()
+	var id int64
+	if err := r.DB().Raw("SELECT last_insert_rowid()").Row().Scan(&id); err != nil {
+		t.Fatalf("read last_insert_rowid for %s: %v", label, err)
+	}
+	if id <= 0 {
+		t.Fatalf("invalid last_insert_rowid for %s: %d", label, id)
+	}
+	return id
+}
+
+func mustQueryInt(t *testing.T, r *repo.Repository, query string, args ...interface{}) int {
+	t.Helper()
+	var v int
+	if err := r.DB().Raw(query, args...).Row().Scan(&v); err != nil {
+		t.Fatalf("query int failed: %v (query=%q)", err, query)
+	}
+	return v
+}
+
+func mustQueryInt64(t *testing.T, r *repo.Repository, query string, args ...interface{}) int64 {
+	t.Helper()
+	var v int64
+	if err := r.DB().Raw(query, args...).Row().Scan(&v); err != nil {
+		t.Fatalf("query int64 failed: %v (query=%q)", err, query)
+	}
+	return v
+}
+
+func mustQueryString(t *testing.T, r *repo.Repository, query string, args ...interface{}) string {
+	t.Helper()
+	var v string
+	if err := r.DB().Raw(query, args...).Row().Scan(&v); err != nil {
+		t.Fatalf("query string failed: %v (query=%q)", err, query)
+	}
+	return v
+}
+
+func mustQueryInt64Int(t *testing.T, r *repo.Repository, query string, args ...interface{}) (int64, int) {
+	t.Helper()
+	var a int64
+	var b int
+	if err := r.DB().Raw(query, args...).Row().Scan(&a, &b); err != nil {
+		t.Fatalf("query int64+int failed: %v (query=%q)", err, query)
+	}
+	return a, b
+}
+
+func tryQueryString(t *testing.T, r *repo.Repository, query string, args ...interface{}) (string, error) {
+	t.Helper()
+	var v string
+	err := r.DB().Raw(query, args...).Row().Scan(&v)
+	if err != nil {
+		return "", err
+	}
+	return v, nil
+}
+
+func mustQueryNullString(t *testing.T, r *repo.Repository, query string, args ...interface{}) sql.NullString {
+	t.Helper()
+	var v sql.NullString
+	if err := r.DB().Raw(query, args...).Row().Scan(&v); err != nil {
+		t.Fatalf("query null string failed: %v (query=%q)", err, query)
+	}
+	return v
+}
+
+func mustQueryTwoNullStrings(t *testing.T, r *repo.Repository, query string, args ...interface{}) (sql.NullString, sql.NullString) {
+	t.Helper()
+	var a sql.NullString
+	var b sql.NullString
+	if err := r.DB().Raw(query, args...).Row().Scan(&a, &b); err != nil {
+		t.Fatalf("query two null strings failed: %v (query=%q)", err, query)
+	}
+	return a, b
+}
+
+func mustQueryNodePorts(t *testing.T, r *repo.Repository, query string, args ...interface{}) map[int64]int {
+	t.Helper()
+	rows, err := r.DB().Raw(query, args...).Rows()
+	if err != nil {
+		t.Fatalf("query node ports failed: %v (query=%q)", err, query)
+	}
+	defer rows.Close()
+
+	out := make(map[int64]int)
+	for rows.Next() {
+		var nodeID int64
+		var port int
+		if err := rows.Scan(&nodeID, &port); err != nil {
+			t.Fatalf("scan node ports row failed: %v (query=%q)", err, query)
+		}
+		out[nodeID] = port
+	}
+	if err := rows.Err(); err != nil {
+		t.Fatalf("iterate node ports rows failed: %v (query=%q)", err, query)
+	}
+	return out
+}
+
+func tryQueryInt(t *testing.T, r *repo.Repository, query string, args ...interface{}) (int, error) {
+	t.Helper()
+	var v int
+	err := r.DB().Raw(query, args...).Row().Scan(&v)
+	if err != nil {
+		return 0, err
+	}
+	return v, nil
+}