Add unit test for set_api_config_content

Author: cboulay

testing/CMakeLists.txt

@@ -79,6 +79,11 @@ target_link_libraries(lsl_test_internal PRIVATE lslobj lslboost common catch_mai
 # Pretend that lsl_test_internal is part of a shared lib so that it can use the __export symbols lslobj. REQ by MinGW.
 target_compile_definitions(lsl_test_internal PRIVATE LIBLSL_EXPORTS)
 
+# runtime_config test needs a fresh api_config singleton, so it lives in its own executable.
+add_executable(lsl_test_runtime_config int/runtime_config.cpp)
+target_link_libraries(lsl_test_runtime_config PRIVATE lslobj lslboost common catch_main)
+target_compile_definitions(lsl_test_runtime_config PRIVATE LIBLSL_EXPORTS)
+
 if(LSL_BENCHMARKS)
 	# to get somewhat reproducible performance numbers:
 	# /usr/bin/time -v testing/lsl_test_exported --benchmark-samples 100  bounce
@@ -94,7 +99,7 @@ if(LSL_BENCHMARKS)
 	)
 endif()
 
-set(LSL_TESTS lsl_test_exported lsl_test_internal)
+set(LSL_TESTS lsl_test_exported lsl_test_internal lsl_test_runtime_config)
 foreach(lsltest ${LSL_TESTS})
 	add_test(NAME ${lsltest} COMMAND ${lsltest} --wait-for-keypress never)
 	if(LSL_INSTALL)

testing/int/runtime_config.cpp

@@ -0,0 +1,23 @@
+#include "api_config.h"
+#include <catch2/catch_test_macros.hpp>
+
+// Verifies that configuration provided via the runtime-config API is picked up
+// on singleton initialization. Because api_config::get_instance() is guarded by
+// std::call_once, only the first configuration wins per-process. This test
+// therefore lives in its own executable so the singleton starts fresh.
+
+TEST_CASE("runtime config content overrides defaults", "[api_config][runtime_config]") {
+	lsl::api_config::set_api_config_content(
+		"[lab]\n"
+		"SessionID = runtime_config_test\n"
+		"[ports]\n"
+		"BasePort = 30000\n"
+		"[tuning]\n"
+		"UseProtocolVersion = 100\n");
+
+	const auto *cfg = lsl::api_config::get_instance();
+	REQUIRE(cfg != nullptr);
+	CHECK(cfg->session_id() == "runtime_config_test");
+	CHECK(cfg->base_port() == 30000);
+	CHECK(cfg->use_protocol_version() == 100);
+}