diff --git a/libs/cputimeinstate/testtimeinstate.cpp b/libs/cputimeinstate/testtimeinstate.cpp
index 9837865..d4b8738 100644
--- a/libs/cputimeinstate/testtimeinstate.cpp
+++ b/libs/cputimeinstate/testtimeinstate.cpp
@@ -12,45 +12,46 @@
 using std::vector;
 
 TEST(TimeInStateTest, SingleUid) {
-    vector<vector<uint64_t>> times;
-    ASSERT_TRUE(getUidCpuFreqTimes(0, &times));
-    EXPECT_FALSE(times.empty());
+    auto times = getUidCpuFreqTimes(0);
+    ASSERT_TRUE(times.has_value());
+    EXPECT_FALSE(times->empty());
 }
 
 TEST(TimeInStateTest, AllUid) {
     vector<size_t> sizes;
-    std::unordered_map<uint32_t, vector<vector<uint64_t>>> map;
-    ASSERT_TRUE(getUidsCpuFreqTimes(&map));
+    auto map = getUidsCpuFreqTimes();
+    ASSERT_TRUE(map.has_value());
 
-    ASSERT_FALSE(map.empty());
+    ASSERT_FALSE(map->empty());
 
-    auto firstEntry = map.begin()->second;
+    auto firstEntry = map->begin()->second;
     for (const auto &subEntry : firstEntry) sizes.emplace_back(subEntry.size());
 
-    for (const auto &vec : map) {
+    for (const auto &vec : *map) {
         ASSERT_EQ(vec.second.size(), sizes.size());
         for (size_t i = 0; i < vec.second.size(); ++i) ASSERT_EQ(vec.second[i].size(), sizes[i]);
     }
 }
 
 TEST(TimeInStateTest, RemoveUid) {
-    vector<vector<uint64_t>> times, times2;
-    ASSERT_TRUE(getUidCpuFreqTimes(0, &times));
-    ASSERT_FALSE(times.empty());
+    auto times = getUidCpuFreqTimes(0);
+    ASSERT_TRUE(times.has_value());
+    ASSERT_FALSE(times->empty());
 
     uint64_t sum = 0;
-    for (size_t i = 0; i < times.size(); ++i) {
-        for (auto x : times[i]) sum += x;
+    for (size_t i = 0; i < times->size(); ++i) {
+        for (auto x : (*times)[i]) sum += x;
     }
     ASSERT_GT(sum, (uint64_t)0);
 
     ASSERT_TRUE(clearUidCpuFreqTimes(0));
 
-    ASSERT_TRUE(getUidCpuFreqTimes(0, &times2));
-    ASSERT_EQ(times2.size(), times.size());
-    for (size_t i = 0; i < times.size(); ++i) {
-        ASSERT_EQ(times2[i].size(), times[i].size());
-        for (size_t j = 0; j < times[i].size(); ++j) ASSERT_LE(times2[i][j], times[i][j]);
+    auto times2 = getUidCpuFreqTimes(0);
+    ASSERT_TRUE(times2.has_value());
+    ASSERT_EQ(times2->size(), times->size());
+    for (size_t i = 0; i < times->size(); ++i) {
+        ASSERT_EQ((*times2)[i].size(), (*times)[i].size());
+        for (size_t j = 0; j < (*times)[i].size(); ++j) ASSERT_LE((*times2)[i][j], (*times)[i][j]);
     }
 }