code: сделал тест на пустой вектор

project/histogram.cpp

@@ -5,6 +5,12 @@ using namespace std;
 
 
 void find_minmax(vector<double> numbers, double& min, double& max)
+{
+    if (numbers.empty())
+    {
+        min = max = 0;
+    }
+    else
     {
         min = numbers[0];
         max = numbers[0];
@@ -19,6 +25,7 @@ void find_minmax(vector<double> numbers, double& min, double& max)
                 max = x;
             }
         }
+    }
     return;
 }
 

unittest.cpp

@@ -34,7 +34,8 @@ TEST_CASE("vector with same elements") {
 TEST_CASE("void vector") {
     double min = 0;
     double max = 0;
-    find_minmax({0}, min, max);
+    std::vector<double> numbers {};
+    find_minmax( numbers, min, max);
     CHECK(min == 0);
     CHECK(max == 0);
 }