Make clickhouse-test to calculate coverage on a per-test basis

tests/clickhouse-test

@@ -1175,6 +1175,12 @@ class TestCase:
         description_full += result.description
 
         if BuildFlags.SANITIZE_COVERAGE in args.build_flags:
+            clickhouse_execute(
+                args,
+                f"INSERT INTO system.coverage SELECT '{self.case}', coverage()",
+                retry_error_codes=True,
+            )
+
             coverage = clickhouse_execute(
                 args,
                 f"SELECT length(coverage())",
@@ -1241,6 +1247,14 @@ class TestCase:
                 + pattern
             )
 
+        # We want to calculate per-test code coverage. That's why we reset it before each test.
+        if BuildFlags.SANITIZE_COVERAGE in args.build_flags:
+            clickhouse_execute(
+                args,
+                "SYSTEM RESET COVERAGE",
+                retry_error_codes=True,
+            )
+
         command = pattern.format(**params)
 
         proc = Popen(command, shell=True, env=os.environ)
@@ -2349,6 +2363,18 @@ def main(args):
         print(f"Failed to create databases for tests: {e}")
         server_died.set()
 
+    if BuildFlags.SANITIZE_COVERAGE in args.build_flags:
+        clickhouse_execute(
+            args,
+            """
+                CREATE TABLE IF NOT EXISTS system.coverage
+                (
+                    test_name String,
+                    coverage Array(UInt64)
+                ) ENGINE = MergeTree ORDER BY test_name;
+            """,
+        )
+
     total_tests_run = 0
 
     for suite in sorted(os.listdir(base_dir), key=suite_key_func):