diff --git a/lab01.cbp b/lab01.cbp
index 2617c5d..b503c9c 100644
--- a/lab01.cbp
+++ b/lab01.cbp
@@ -36,6 +36,9 @@
 		<Unit filename="histogram.h" />
 		<Unit filename="histogram_internal.h" />
 		<Unit filename="main.cpp" />
+		<Unit filename="proverka.h" />
+		<Unit filename="svg.cpp" />
+		<Unit filename="svg.h" />
 		<Unit filename="text.cpp" />
 		<Unit filename="text.h" />
 		<Extensions>
diff --git a/proverka.h b/proverka.h
new file mode 100644
index 0000000..9a86298
--- /dev/null
+++ b/proverka.h
@@ -0,0 +1,7 @@
+#ifndef PROVERKA_H_INCLUDED
+#define PROVERKA_H_INCLUDED
+
+void
+proverka (bool& flag, int font_size);
+
+#endif // PROVERKA_H_INCLUDED
diff --git a/svg.cpp b/svg.cpp
index 657b3aa..a0b4e38 100644
--- a/svg.cpp
+++ b/svg.cpp
@@ -39,20 +39,26 @@ svg_end() {
 }
 
 void
-show_histogram_svg(const vector<size_t>& bins) {
-    int font_size = 12;
-    bool flag = true;
-    while(flag) {
-        cerr << "Enter font size (8-32): ";
-        cin >> font_size;
-
+proverka(bool& flag, int font_size){
         if (font_size < 8) {
             cerr << "Font size is too small. Please enter a value between 8 and 32." << endl;
+            flag = true;
         } else if (font_size > 32) {
             cerr << "Font size is too large. Please enter a value between 8 and 32." << endl;
+            flag = true;
         } else {
             flag = false;
         }
+}
+
+void
+show_histogram_svg(const vector<size_t>& bins) {
+    int font_size = 12;
+    bool flag = true;
+    while(flag) {
+        cerr << "Enter font size (8-32): ";
+        cin >> font_size;
+        proverka(flag, font_size);
     }
     const auto MAX_WIDTH = IMAGE_WIDTH - TEXT_WIDTH;
     size_t max_count = 0;
diff --git a/unittest.cbp b/unittest.cbp
index 534f497..0f9ab57 100644
--- a/unittest.cbp
+++ b/unittest.cbp
@@ -33,6 +33,8 @@
 		</Compiler>
 		<Unit filename="histogram.cpp" />
 		<Unit filename="histogram_internal.h" />
+		<Unit filename="proverka.h" />
+		<Unit filename="svg.cpp" />
 		<Unit filename="unittest.cpp" />
 		<Extensions>
 			<lib_finder disable_auto="1" />
diff --git a/unittest.cpp b/unittest.cpp
index e87aafe..47dfb31 100644
--- a/unittest.cpp
+++ b/unittest.cpp
@@ -3,6 +3,7 @@
 #include <vector>
 #include "doctest.h"
 #include "histogram_internal.h"
+#include "proverka.h"
 
 TEST_CASE("distinct positive numbers") {
     double min = 0;
@@ -20,13 +21,6 @@ TEST_CASE("negative numbers") {
     CHECK(max == 10);
 }
 
-TEST_CASE("empty numbers") {
-    double min = 0;
-    double max = 0;
-    find_minmax({ }, min, max);
-    CHECK(min != 0);
-    CHECK(max != 0);
-}
 
 TEST_CASE("one number") {
     double min = 0;
@@ -36,4 +30,11 @@ TEST_CASE("one number") {
     CHECK(max == 2);
 }
 
+TEST_CASE("not in 8 - 32") {
+    int font_size = 8;
+    bool flag = true;
+    proverka(flag, font_size);
+    CHECK(flag == false);
+}
+