Fix deprecation warning

Also put iterator into dhandy namespace. I don't
remember why I left it out, and it's probably a
sign I should have not done so.

test/unit/infix_iterator.cpp

@@ -0,0 +1,58 @@
+/* Copyright 2016-2024 Michele Santullo
+ * This file is part of "duckhandy".
+ *
+ * "duckhandy" is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * "duckhandy" is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with "duckhandy".  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "catch2/catch_test_macros.hpp"
+#include "duckhandy/infix_iterator.hpp"
+#include <algorithm>
+#include <sstream>
+#include <vector>
+
+TEST_CASE("infix_iterator tests", "[iterator][infix_iterator]") {
+	using std::vector;
+	using std::string;
+	using std::copy;
+	using std::ostringstream;
+	using dhandy::infix_ostream_iterator;
+
+	{
+		ostringstream oss;
+		vector<string> empty{};
+		copy(empty.begin(), empty.end(), infix_ostream_iterator<string>(oss, "lalala"));
+		CHECK(oss.str() == "");
+	}
+
+	{
+		ostringstream oss;
+		vector<string> data{"apple", "pear", "cherry", "mango"};
+		copy(data.begin(), data.end(), infix_ostream_iterator<string>(oss, "lalala"));
+		CHECK(oss.str() == "applelalalapearlalalacherrylalalamango");
+	}
+
+	{
+		ostringstream oss;
+		vector<int> data{1, 2, 3, 4, 5, 6, 7};
+		copy(data.begin(), data.end(), infix_ostream_iterator<int>(oss, ", "));
+		CHECK(oss.str() == "1, 2, 3, 4, 5, 6, 7");
+	}
+
+	{
+		ostringstream oss;
+		vector<string> data{"just one value"};
+		copy(data.begin(), data.end(), infix_ostream_iterator<string>(oss, ", "));
+		CHECK(oss.str() == "just one value");
+	}
+}

test/unit/meson.build

@@ -9,6 +9,7 @@ unit_test_prog = executable(meson.project_name(),
   'resource_pool_test.cpp',
   'version_test.cpp',
   'tiger_test.cpp',
+  'infix_iterator.cpp',
   install: false,
   dependencies: [sprout_dep, catch2_dep],
   include_directories: [public_incl],