diff --git a/unittest.cpp b/unittest.cpp
index 851208c..3c81003 100644
--- a/unittest.cpp
+++ b/unittest.cpp
@@ -14,7 +14,7 @@ TEST_CASE("distinct positive numbers") {
 TEST_CASE("empty vector"){
     double min = 0;
     double max = 0;
-    find_minmax({ 0, 0 }, min, max);
+    find_minmax({ NULL }, min, max);
     CHECK(min == 0);
     CHECK(max == 0);
 }
@@ -38,7 +38,7 @@ TEST_CASE("only one number"){
 TEST_CASE("distinct negative numbers") {
     double min = 0;
     double max = 0;
-    find_minmax({0, -2}, min, max);
+    find_minmax({-1, -2}, min, max);
     CHECK(min == -2);
-    CHECK(max == 0);
+    CHECK(max == -1);
 }