добавлены тесты

unittest.cpp

@@ -10,3 +10,17 @@ TEST_CASE("distinct positive numbers") {
     CHECK(min == 1);
     CHECK(max == 2);
 }
+TEST_CASE("distinct negative numbers"){
+    double min = 0;
+    double max = 0;
+    find_minmax({-1, -2}, min, max);
+    CHECK(min == -2);
+    CHECK(max == -1);
+}
+TEST_CASE("vector of the same elements"){
+    double min = 0;
+    double max = 0;
+    find_minmax({3,3,3}, min, max);
+    CHECK(min == 3);
+    CHECK(max == 3);
+}