Move tests for back into their own file

Author: davidstone

source/containers/CMakeLists.txt

@@ -241,6 +241,7 @@ target_sources(containers_test PRIVATE
 		test/array.cpp
 		test/assign.cpp
 		test/assign_to_empty.cpp
+		test/back.cpp
 		test/bidirectional_linked_list.cpp
 		test/clear.cpp
 		test/concatenate.cpp

source/containers/back.cpp

@@ -12,7 +12,6 @@ export module containers.back;
 
 import containers.algorithms.advance;
 import containers.begin_end;
-import containers.c_array;
 import containers.is_empty;
 import containers.range;
 
@@ -23,10 +22,4 @@ export constexpr auto back(range auto && r) -> decltype(auto) {
 	return *containers::prev(containers::end(OPERATORS_FORWARD(r)));
 }
 
-} // namespace containers
-
-constexpr containers::c_array<int, 1> one = {5};
-static_assert(containers::back(one) == 5);
-
-constexpr containers::c_array<int, 3> three = {2, 3, 4};
-static_assert(containers::back(three) == 4);
+} // namespace containers

source/containers/test/back.cpp

@@ -0,0 +1,12 @@
+// Copyright David Stone 2024.
+// Distributed under the Boost Software License, Version 1.0.
+// (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+export module containers.test.back;
+
+import containers.array;
+import containers.back;
+
+static_assert(containers::back(containers::array({5})) == 5);
+static_assert(containers::back(containers::array({2, 3, 4})) == 4);