diff --git a/lab_3.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate b/lab_3.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate
index 5771778..9e907e1 100644
Binary files a/lab_3.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate and b/lab_3.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate differ
diff --git a/unittest/unittest.cpp b/unittest/unittest.cpp
index dde844d..8f06592 100644
--- a/unittest/unittest.cpp
+++ b/unittest/unittest.cpp
@@ -1,8 +1,31 @@
-//
-//  unittest.cpp
-//  unittest
-//
-//  Created by Леша Минов on 05.06.2023.
-//
+#define DOCTEST_CONFIG_NO_MULTITHREADING
+#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
+#include "doctest.h"
+#include "histogram_internal.h"
 
-#include "unittest.hpp"
+TEST_CASE("distinct positive numbers") {
+    double min = 0;
+    double max = 0;
+    find_minmax({1, 2}, min, max);
+    CHECK(min == 1);
+    CHECK(max == 2);
+}
+
+TEST_CASE("vector with same elements") {
+    double min = 0;
+    double max = 0;
+    find_minmax({2,2,2}, min, max);
+    CHECK(min == 2);
+    CHECK(max == 2);
+}
+TEST_CASE("distinct positive numbers 2") {
+    double min = 0;
+    double max = 0;
+    std::vector<double>v{2,1};
+    CHECK(v.size() != 0);
+    CHECK(v.size() != 1);
+    find_minmax({1, 2}, min, max);
+    CHECK(min == 1);
+    CHECK(max == 2);
+    CHECK(min != max);
+}
diff --git a/unittest/unittest.xcodeproj/project.pbxproj b/unittest/unittest.xcodeproj/project.pbxproj
index 9931c7a..a9dc519 100644
--- a/unittest/unittest.xcodeproj/project.pbxproj
+++ b/unittest/unittest.xcodeproj/project.pbxproj
@@ -6,10 +6,21 @@
 	objectVersion = 56;
 	objects = {
 
+/* Begin PBXFileReference section */
+		35EA3AD42A2D65C200ED69F1 /* histogram_internal.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; name = histogram_internal.hpp; path = ../histogram_internal.hpp; sourceTree = "<group>"; };
+		35EA3AD52A2D65C200ED69F1 /* histogram.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; name = histogram.cpp; path = ../histogram.cpp; sourceTree = "<group>"; };
+		35EA3AD62A2D65F200ED69F1 /* unittest.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = unittest.cpp; sourceTree = "<group>"; };
+		35EA3AD72A2D65F200ED69F1 /* doctest.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = doctest.hpp; sourceTree = "<group>"; };
+/* End PBXFileReference section */
+
 /* Begin PBXGroup section */
 		35EA3ACD2A2D657900ED69F1 = {
 			isa = PBXGroup;
 			children = (
+				35EA3AD62A2D65F200ED69F1 /* unittest.cpp */,
+				35EA3AD42A2D65C200ED69F1 /* histogram_internal.hpp */,
+				35EA3AD52A2D65C200ED69F1 /* histogram.cpp */,
+				35EA3AD72A2D65F200ED69F1 /* doctest.hpp */,
 			);
 			sourceTree = "<group>";
 		};
diff --git a/unittest/unittest.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate b/unittest/unittest.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate
index b275c28..4b81c84 100644
Binary files a/unittest/unittest.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate and b/unittest/unittest.xcodeproj/project.xcworkspace/xcuserdata/lesaminov.xcuserdatad/UserInterfaceState.xcuserstate differ