diff --git a/unittest.cpp b/unittest.cpp
new file mode 100644
index 0000000..b5b306e
--- /dev/null
+++ b/unittest.cpp
@@ -0,0 +1,18 @@
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "histogram_internal.h"
+
+
+
+TEST_CASE("distinct positive numbers") {
+    double minp = 0;
+    double maxp = 0;
+    std::vector<double>numbers{1,2,3,4,5};
+    CHECK(numbers.size() !=0 );
+    CHECK(numbers.size() !=1 );
+    find_minmax(numbers, minp, maxp);
+    CHECK(minp == 1);
+    CHECK(maxp == 5);
+    CHECK(minp!=maxp);
+}