test: cover GetNumThreads default

Author: aobolensk

modules/core/util/tests/util.cpp

@@ -2,6 +2,8 @@
 
 #include <gtest/gtest.h>
 
+#include <cstdlib>
+#include <libenvpp/detail/get.hpp>
 #include <string_view>
 
 #include "omp.h"
@@ -26,6 +28,16 @@ TEST(util_tests, threads_control_check_openmp_disabled_valgrind) {
   ASSERT_EQ(ppc_num_threads, omp_num_threads);
 }
 
+TEST(util_tests, GetNumThreadsEnvUnsetReturnsOne) {
+  const auto num_threads_env_var = env::get<int>("PPC_NUM_THREADS");
+
+  if (num_threads_env_var.has_value()) {
+    EXPECT_EQ(ppc::util::GetNumThreads(), 1);
+  } else {
+    GTEST_SKIP() << "PPC_NUM_THREADS environment variable is set, skipping test";
+  }
+}
+
 namespace test_ns {
 struct TypeInNamespace {};
 }  // namespace test_ns