diff --git a/Lab1.cbp b/Lab1.cbp
index 97bdf05..0277582 100644
--- a/Lab1.cbp
+++ b/Lab1.cbp
@@ -32,8 +32,14 @@
 			<Add option="-Wall" />
 			<Add option="-fexceptions" />
 		</Compiler>
+		<Unit filename=".gitignore" />
+		<Unit filename="histogram.cpp" />
+		<Unit filename="histogram.h" />
+		<Unit filename="histogram_internal.h" />
 		<Unit filename="main.cpp" />
 		<Unit filename="main.h" />
+		<Unit filename="text.cpp" />
+		<Unit filename="text.h" />
 		<Extensions />
 	</Project>
 </CodeBlocks_project_file>
diff --git a/histogram.cpp b/histogram.cpp
index d526eb7..0bcaa87 100644
--- a/histogram.cpp
+++ b/histogram.cpp
@@ -2,16 +2,28 @@
 
 using namespace std;
 
-static void
-find_minmax(const vector<double>& numbers, double& min, double& max)
+void
+find_minmax(const vector<double>& numbers, double& min, double& max, bool& empty_vector)
 {
-    min = numbers[0];
-    max = numbers[0];
-    // (здесь код поиска минимума и максимума)
-    for (double value : numbers)
+    if (numbers.empty())
     {
-        if (value < min) {min = value;}
-        else if (value > max) {max = value;}
+        empty_vector = true;
+    }
+    else
+    {
+        min = numbers[0];
+        max = numbers[0];
+        for (double x : numbers)
+        {
+            if (x > max )
+            {
+                max = x;
+            }
+            if (x < min)
+            {
+                min = x;
+            }
+        }
     }
 }
 
@@ -19,10 +31,22 @@ vector<size_t>
 make_histogram(const vector<double>& numbers, size_t& bin_count)
 {
     double min, max;
-    find_minmax(numbers, min, max);
+    bool empty_vector = false;
+    find_minmax(numbers, min, max, empty_vector);
+
 
     double bin_size = (max - min) / bin_count;
     vector<size_t> bins(bin_count);
+
+    if (empty_vector)
+    {
+        for (size_t y : bins)
+        {
+            y = 0;
+        }
+    }
+
+
     for (size_t i = 0; i < numbers.size(); i++)
     {
         for (size_t j = i + 1; j < numbers.size(); j++)
diff --git a/histogram_internal.h b/histogram_internal.h
new file mode 100644
index 0000000..8f2b497
--- /dev/null
+++ b/histogram_internal.h
@@ -0,0 +1,9 @@
+#ifndef HISTOGRAM_INTERNAL_H_INCLUDED
+#define HISTOGRAM_INTERNAL_H_INCLUDED
+
+#include <vector>
+
+void
+find_minmax(const std::vector<double>& numbers, double& min, double& max, bool& empty_vector);
+
+#endif // HISTOGRAM_INTERNAL_H_INCLUDED
diff --git a/text.cpp b/text.cpp
index aceb930..011f6ff 100644
--- a/text.cpp
+++ b/text.cpp
@@ -17,6 +17,11 @@ show_histogram_text(const vector<size_t>& bins, size_t& bin_count) {
         }
     }
 
+    if (max_count == 0)
+    {
+        max_count = 1;
+    }
+
     for (size_t bin : bins)
     {
         if (bin < 100) cout << " ";
diff --git a/unittest.cpp b/unittest.cpp
new file mode 100644
index 0000000..74f357e
--- /dev/null
+++ b/unittest.cpp
@@ -0,0 +1,54 @@
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "histogram_internal.h"
+
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    bool empty_vector = false;
+    find_minmax({1, 2}, min, max, empty_vector);
+    CHECK(empty_vector == false);
+    CHECK(min == 1);
+    CHECK(max == 2);
+}
+
+TEST_CASE("single number") {
+    double min = 0;
+    double max = 0;
+    bool empty_vector = false;
+    find_minmax({1}, min, max, empty_vector);
+    CHECK(empty_vector == false);
+    CHECK(min == 1);
+    CHECK(max == 1);
+}
+
+TEST_CASE("negative numbers") {
+    double min = 0;
+    double max = 0;
+    bool empty_vector = false;
+    find_minmax({-1, -2}, min, max, empty_vector);
+    CHECK(empty_vector == false);
+    CHECK(min == -2);
+    CHECK(max == -1);
+}
+
+TEST_CASE("identical numbers") {
+    double min = 0;
+    double max = 0;
+    bool empty_vector = false;
+    find_minmax({2, 2}, min, max, empty_vector);
+    CHECK(empty_vector == false);
+    CHECK(min == 2);
+    CHECK(max == 2);
+}
+
+TEST_CASE("empty vector") {
+    double min = 0;
+    double max = 0;
+    bool empty_vector = false;
+    find_minmax({}, min, max, empty_vector);
+    CHECK(empty_vector == true);
+    CHECK(min == 0);
+    CHECK(max == 0);
+}