First attempt

tests/test_fixed_string.cpp

@@ -0,0 +1,27 @@
+#include <catch2/catch_test_macros.hpp>
+#include <kpn/fixed_string.hpp>
+
+using namespace kpn;
+
+TEST_CASE("fixed_string equality", "[fixed_string]") {
+    constexpr fixed_string a("img");
+    constexpr fixed_string b("img");
+    constexpr fixed_string c("sigma");
+    STATIC_REQUIRE(a == b);
+    STATIC_REQUIRE(!(a == c));
+}
+
+TEST_CASE("fixed_string view", "[fixed_string]") {
+    constexpr fixed_string s("hello");
+    REQUIRE(s.view() == "hello");
+}
+
+TEST_CASE("index_of hit", "[fixed_string]") {
+    constexpr auto idx = index_of<fixed_string("b"), fixed_string("a"), fixed_string("b"), fixed_string("c")>();
+    STATIC_REQUIRE(idx == 1);
+}
+
+TEST_CASE("index_of miss returns npos", "[fixed_string]") {
+    constexpr auto idx = index_of<fixed_string("z"), fixed_string("a"), fixed_string("b")>();
+    STATIC_REQUIRE(idx == npos);
+}