diff --git a/unitest.cpp b/unitest.cpp
new file mode 100644
index 0000000..b33aece
--- /dev/null
+++ b/unitest.cpp
@@ -0,0 +1,18 @@
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "histogram_internal.h"
+#include <vector>
+#include <iostream>
+TEST_CASE("distinct positive numbers")
+{
+    double min = 0;
+    double max = 0;
+    std::vector<double>v{1};
+    CHECK(v.size() != 0);
+    CHECK(v.size() != 1);
+    find_minmax(v, min, max);
+    CHECK(min == 1);
+    CHECK(max == 2);
+    CHECK(min != max);
+}