diff --git a/unittest.cpp b/unittest.cpp
index a9ba7e5..b4062a4 100644
--- a/unittest.cpp
+++ b/unittest.cpp
@@ -10,3 +10,31 @@ TEST_CASE("distinct positive numbers") {
     CHECK(min == 1);
     CHECK(max == 2);
 }
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({}, min, max);
+    CHECK(min == 0);
+    CHECK(max == 0);
+}
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({1}, min, max);
+    CHECK(min == 1);
+    CHECK(max == 1);
+}
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({-1, 2}, min, max);
+    CHECK(min == -1);
+    CHECK(max == 2);
+}
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({2, 2, 2, 2}, min, max);
+    CHECK(min == 2);
+    CHECK(max == 2);
+}