Unit tests for index sequence utils

tests/CMakeLists.txt

@@ -9,6 +9,7 @@ add_executable(unit_tests
     static_tests/functional/static_if_tests.cpp
     static_tests/functional/mpl.cpp
     static_tests/functional/same_or_void.cpp
+    static_tests/functional/index_sequence_util.cpp
     static_tests/functional/tuple_conc.cpp
     static_tests/functional/tuple_filter.cpp
     static_tests/functional/tuple_traits.cpp

tests/static_tests/functional/index_sequence_util.cpp

@@ -0,0 +1,23 @@
+#include <sqlite_orm/sqlite_orm.h>
+#include <catch2/catch_all.hpp>
+
+using std::index_sequence;
+using namespace sqlite_orm;
+using internal::flatten_idxseq_t;
+using internal::index_sequence_value_at;
+
+TEST_CASE("index sequence value at") {
+    STATIC_REQUIRE(index_sequence_value_at<0>(index_sequence<1, 3>{}) == 1);
+#if defined(SQLITE_ORM_PACK_INDEXING_SUPPORTED) || defined(SQLITE_ORM_FOLD_EXPRESSIONS_SUPPORTED)
+    STATIC_REQUIRE(index_sequence_value_at<1>(index_sequence<1, 3>{}) == 3);
+#endif
+}
+
+TEST_CASE("flatten index sequence") {
+    STATIC_REQUIRE(std::is_same<flatten_idxseq_t<>, index_sequence<>>::value);
+    STATIC_REQUIRE(std::is_same<flatten_idxseq_t<index_sequence<1, 3>>, index_sequence<1, 3>>::value);
+    STATIC_REQUIRE(
+        std::is_same<flatten_idxseq_t<index_sequence<1, 3>, index_sequence<1, 3>>, index_sequence<1, 3, 1, 3>>::value);
+    STATIC_REQUIRE(std::is_same<flatten_idxseq_t<index_sequence<1, 3>, index_sequence<1, 3>, index_sequence<1, 3>>,
+                                index_sequence<1, 3, 1, 3, 1, 3>>::value);
+}