diff --git a/unittest/unittest.cpp b/unittest/unittest.cpp
new file mode 100644
index 0000000..be25bcc
--- /dev/null
+++ b/unittest/unittest.cpp
@@ -0,0 +1,49 @@
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "C:\Users\User\Desktop\cs-lab03\histogram_internal.h"
+#include "C:\Users\User\Desktop\cs-lab03\svg.h"
+
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({ }, min, max);
+    CHECK(min == 0);
+    CHECK(max == 0);
+}
+
+TEST_CASE("distinct identical numbers") {
+    double min = 10000;
+    double max = 0;
+    find_minmax({ 5, 5 }, min, max);
+    CHECK(min == 5);
+    CHECK(max == 5);
+}
+
+TEST_CASE("distinct one number") {
+    double min = 10000;
+    double max = 0;
+    find_minmax({ 3 }, min, max);
+    CHECK(min == 3);
+    CHECK(max == 3);
+}
+
+TEST_CASE("distinct negative numbers") {
+    double min = 1000;
+    double max = -1000;
+    find_minmax({ -3, -1 }, min, max);
+    CHECK(min == -3);
+    CHECK(max == -1);
+}
+
+TEST_CASE("take percent") {
+    int x = 0;
+    pers(1, 20, x);
+    CHECK(x < 10);
+}
+
+TEST_CASE("take percent") {
+    int x = 0;
+    pers(5, 10, x);
+    CHECK(x == 50);
+}