diff --git a/src/Common/Exception.h b/src/Common/Exception.h
index a4774a89f6a..4e54c411bf1 100644
--- a/src/Common/Exception.h
+++ b/src/Common/Exception.h
@@ -244,6 +244,15 @@ private:
     const char * className() const noexcept override { return "DB::ErrnoException"; }
 };
 
+/// An exception to use in unit tests to test interfaces.
+/// It is distinguished from others, so it does not have to be logged.
+class TestException : public Exception
+{
+public:
+    using Exception::Exception;
+};
+
+
 using Exceptions = std::vector<std::exception_ptr>;
 
 /** Try to write an exception to the log (and forget about it).
diff --git a/src/Common/tests/gtest_shell_command.cpp b/src/Common/tests/gtest_shell_command.cpp
index d6d0a544e9b..0ea96da9da2 100644
--- a/src/Common/tests/gtest_shell_command.cpp
+++ b/src/Common/tests/gtest_shell_command.cpp
@@ -54,16 +54,3 @@ TEST(ShellCommand, ExecuteWithInput)
 
     EXPECT_EQ(res, "Hello, world!\n");
 }
-
-TEST(ShellCommand, AutoWait)
-{
-    // <defunct> hunting:
-    for (int i = 0; i < 1000; ++i)
-    {
-        auto command = ShellCommand::execute("echo " + std::to_string(i));
-        //command->wait(); // now automatic
-    }
-
-    // std::cerr << "inspect me: ps auxwwf\n";
-    // std::this_thread::sleep_for(std::chrono::seconds(100));
-}
diff --git a/src/Interpreters/InterpreterShowTablesQuery.cpp b/src/Interpreters/InterpreterShowTablesQuery.cpp
index 51038aaca46..78580f2ec02 100644
--- a/src/Interpreters/InterpreterShowTablesQuery.cpp
+++ b/src/Interpreters/InterpreterShowTablesQuery.cpp
@@ -121,9 +121,18 @@ String InterpreterShowTablesQuery::getRewrittenQuery()
     if (query.merges)
     {
         WriteBufferFromOwnString rewritten_query;
-        rewritten_query << "SELECT table, database, round((elapsed * (1 / merges.progress)) - merges.elapsed, 2) AS estimate_complete, round(elapsed,2) elapsed, "
-                           "round(progress*100, 2) AS progress, is_mutation, formatReadableSize(total_size_bytes_compressed) AS size_compressed, "
-                           "formatReadableSize(memory_usage) AS memory_usage FROM system.merges";
+        rewritten_query << R"(
+            SELECT
+                table,
+                database,
+                merges.progress > 0 ? round(merges.elapsed * (1 - merges.progress) / merges.progress, 2) : NULL AS estimate_complete,
+                round(elapsed, 2) AS elapsed,
+                round(progress * 100, 2) AS progress,
+                is_mutation,
+                formatReadableSize(total_size_bytes_compressed) AS size_compressed,
+                formatReadableSize(memory_usage) AS memory_usage
+            FROM system.merges
+            )";
 
         if (!query.like.empty())
         {
diff --git a/src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp b/src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp
index 8cb0badc19b..4a4deb07eee 100644
--- a/src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp
+++ b/src/Storages/MergeTree/MergeTreeBackgroundExecutor.cpp
@@ -155,6 +155,10 @@ void printExceptionWithRespectToAbort(LoggerPtr log, const String & query_id)
     {
         std::rethrow_exception(ex);
     }
+    catch (const TestException &) // NOLINT
+    {
+        /// Exception from a unit test, ignore it.
+    }
     catch (const Exception & e)
     {
         NOEXCEPT_SCOPE({
diff --git a/src/Storages/MergeTree/tests/gtest_executor.cpp b/src/Storages/MergeTree/tests/gtest_executor.cpp
index 6f34eb4dfbd..c7057ce87c6 100644
--- a/src/Storages/MergeTree/tests/gtest_executor.cpp
+++ b/src/Storages/MergeTree/tests/gtest_executor.cpp
@@ -34,7 +34,7 @@ public:
 
         auto choice = distribution(generator);
         if (choice == 0)
-            throw std::runtime_error("Unlucky...");
+            throw TestException();
 
         return false;
     }
@@ -48,7 +48,7 @@ public:
     {
         auto choice = distribution(generator);
         if (choice == 0)
-            throw std::runtime_error("Unlucky...");
+            throw TestException();
     }
 
     Priority getPriority() const override { return {}; }
diff --git a/tests/integration/test_disk_configuration/test.py b/tests/integration/test_disk_configuration/test.py
index c003ff85755..afc5303298c 100644
--- a/tests/integration/test_disk_configuration/test.py
+++ b/tests/integration/test_disk_configuration/test.py
@@ -208,13 +208,21 @@ def test_merge_tree_custom_disk_setting(start_cluster):
                 secret_access_key='minio123');
     """
     )
-    count = len(list(minio.list_objects(cluster.minio_bucket, "data/", recursive=True)))
+
+    list1 = list(minio.list_objects(cluster.minio_bucket, "data/", recursive=True))
+    count1 = len(list1)
+
     node1.query(f"INSERT INTO {TABLE_NAME}_3 SELECT number FROM numbers(100)")
     assert int(node1.query(f"SELECT count() FROM {TABLE_NAME}_3")) == 100
-    assert (
-        len(list(minio.list_objects(cluster.minio_bucket, "data/", recursive=True)))
-        == count
-    )
+
+    list2 = list(minio.list_objects(cluster.minio_bucket, "data/", recursive=True))
+    count2 = len(list2)
+
+    if count1 != count2:
+        print("list1: ", list1)
+        print("list2: ", list2)
+
+    assert count1 == count2
     assert (
         len(list(minio.list_objects(cluster.minio_bucket, "data2/", recursive=True)))
         > 0