1 files changed, 136 insertions, 0 deletions
diff --git a/nihil/tests/error.cc b/nihil/tests/error.cc
new file mode 100644
index 0000000..7b079fd
--- /dev/null
+++ b/nihil/tests/error.cc
@@ -0,0 +1,136 @@
+/*
+ * This source code is released into the public domain.
+ */
+
+#include <cerrno>
+#include <cstring>
+#include <system_error>
+
+#include <catch2/catch_test_macros.hpp>
+
+import nihil;
+
+TEST_CASE("error: invariants", "[nihil]")
+{
+	static_assert(std::destructible<nihil::error>);
+	static_assert(std::default_initializable<nihil::error>);
+	static_assert(std::move_constructible<nihil::error>);
+	static_assert(std::copy_constructible<nihil::error>);
+	static_assert(std::equality_comparable<nihil::error>);
+	static_assert(std::totally_ordered<nihil::error>);
+	static_assert(std::swappable<nihil::error>);
+	static_assert(std::regular<nihil::error>);
+}
+
+TEST_CASE("error: construct from string", "[nihil]")
+{
+	auto e = nihil::error("an error");
+	REQUIRE(e.str() == e.what());
+	REQUIRE(e.what() == "an error");
+	REQUIRE(std::format("{}", e) == e.what());
+}
+
+TEST_CASE("error: construct from std::error_condition", "[nihil]")
+{
+	auto code = std::make_error_condition(std::errc::invalid_argument);
+	auto e = nihil::error(code);
+
+	REQUIRE(e.cause().has_value() == false);
+	REQUIRE(e.code().has_value() == false);
+	REQUIRE(e.condition().has_value() == true);
+
+	REQUIRE(e == std::errc::invalid_argument);
+	REQUIRE(e != std::errc::no_such_file_or_directory);
+
+	REQUIRE(e.str() == e.what());
+	REQUIRE(e.what() == std::strerror(EINVAL));
+	REQUIRE(std::format("{}", e) == e.what());
+}
+
+TEST_CASE("error: construct from std::errc", "[nihil]")
+{
+	auto e = nihil::error(std::errc::invalid_argument);
+
+	REQUIRE(e.cause().has_value() == false);
+	REQUIRE(e.code().has_value() == false);
+	REQUIRE(e.condition().has_value() == true);
+
+	REQUIRE(e == std::errc::invalid_argument);
+	REQUIRE(e != std::errc::no_such_file_or_directory);
+
+	REQUIRE(e.str() == e.what());
+	REQUIRE(e.what() == std::strerror(EINVAL));
+	REQUIRE(std::format("{}", e) == e.what());
+}
+
+TEST_CASE("error: compound error", "[nihil]")
+{
+	using namespace std::literals;
+
+	auto e = nihil::error("cannot open file",
+			nihil::error(std::errc::no_such_file_or_directory));
+
+	REQUIRE(e.cause().has_value() == true);
+	REQUIRE(e.code().has_value() == false);
+	REQUIRE(e.condition().has_value() == false);
+
+	REQUIRE(e.cause() == std::errc::no_such_file_or_directory);
+	REQUIRE(e.str() == "cannot open file");
+	REQUIRE(e.what() == ("cannot open file: "s + std::strerror(ENOENT)));
+	REQUIRE(std::format("{}", e) == e.what());
+}
+
+TEST_CASE("error: operator== with strings", "[nihil]")
+{
+	auto e1 = nihil::error("error");
+	auto e2 = nihil::error("error");
+	auto e3 = nihil::error("an error");
+
+	REQUIRE(e1 == e2);
+	REQUIRE(e1 != e3);
+}
+
+TEST_CASE("error: operator< with strings", "[nihil]")
+{
+	auto e1 = nihil::error("aaa");
+	auto e2 = nihil::error("zzz");
+
+	REQUIRE(e1 < e2);
+}
+
+TEST_CASE("error: operator== with a cause", "[nihil]")
+{
+	auto e1 = nihil::error("error", nihil::error("cause 1"));
+	auto e2 = nihil::error("error", nihil::error("cause 2"));
+
+	REQUIRE(e1 == e2);
+}
+
+TEST_CASE("error: operator== with error_conditions", "[nihil]")
+{
+	auto e1 = nihil::error(std::errc::invalid_argument);
+	auto e2 = nihil::error(std::errc::invalid_argument);
+	auto e3 = nihil::error(std::errc::permission_denied);
+
+	REQUIRE(e1 == e2);
+	REQUIRE(e1 != e3);
+}
+
+TEST_CASE("error: std::format with string", "[nihil]")
+{
+	auto err = nihil::error("an error");
+	REQUIRE(std::format("{}", err) == "an error");
+}
+
+TEST_CASE("error: std::format with std::errc", "[nihil]")
+{
+	auto err = nihil::error(std::errc::invalid_argument);
+	REQUIRE(std::format("{}", err) == std::strerror(EINVAL));
+}
+
+TEST_CASE("error: std::format with cause", "[nihil]")
+{
+	auto err = nihil::error("an error", std::errc::invalid_argument);
+	REQUIRE(std::format("{}", err) == "an error: Invalid argument");
+}
+