diff --git a/tdutils/test/gzip.cpp b/tdutils/test/gzip.cpp
index f1c4be18..4c7bd683 100644
--- a/tdutils/test/gzip.cpp
+++ b/tdutils/test/gzip.cpp
@@ -11,28 +11,34 @@
 #include "td/utils/logging.h"
 #include "td/utils/Status.h"
 #include "td/utils/tests.h"
+#include "td/utils/Time.h"
 
 static void encode_decode(td::string s) {
   auto r = td::gzencode(s, 2);
   ASSERT_TRUE(!r.empty());
-  if (r.empty()) {
-    return;
-  }
-  auto new_s = td::gzdecode(r.as_slice());
-  ASSERT_TRUE(!new_s.empty());
-  if (new_s.empty()) {
-    return;
-  }
-  ASSERT_EQ(s, new_s.as_slice().str());
+  ASSERT_EQ(s, td::gzdecode(r.as_slice()));
 }
 
 TEST(Gzip, gzencode_gzdecode) {
-  auto str = td::rand_string(0, 127, 1000);
-  encode_decode(str);
-  str = td::rand_string('a', 'z', 1000000);
-  encode_decode(str);
-  str = td::string(1000000, 'a');
-  encode_decode(str);
+  encode_decode(td::rand_string(0, 255, 1000));
+  encode_decode(td::rand_string('a', 'z', 1000000));
+  encode_decode(td::string(1000000, 'a'));
+}
+
+static void test_gzencode(td::string s) {
+  auto begin_time = td::Time::now();
+  auto r = td::gzencode(s, td::max(2, static_cast<int>(100 / s.size())));
+  ASSERT_TRUE(!r.empty());
+  LOG(INFO) << "Encoded string of size " << s.size() << " in " << (td::Time::now() - begin_time)
+            << " with compression ratio " << r.size() * 1.0 / s.size();
+}
+
+TEST(Gzip, gzencode) {
+  for (size_t len = 1; len <= 10000000; len *= 10) {
+    test_gzencode(td::rand_string('a', 'a', len));
+    test_gzencode(td::rand_string('a', 'z', len));
+    test_gzencode(td::rand_string(0, 255, len));
+  }
 }
 
 TEST(Gzip, flow) {