fuzz: Print coverage summary after run_once

Author: MarcoFalke

test/fuzz/test_runner.py

@@ -347,13 +347,18 @@ def job(t, args):
                 text=True,
             )
             output += result.stderr
-            return output, result
+            return output, result, t
 
         jobs.append(fuzz_pool.submit(job, t, args))
 
+    stats = []
     for future in as_completed(jobs):
-        output, result = future.result()
+        output, result, target = future.result()
         logging.debug(output)
+        if using_libfuzzer:
+            done_stat = [l for l in output.splitlines() if "DONE" in l]
+            assert len(done_stat) == 1
+            stats.append((target, done_stat[0]))
         try:
             result.check_returncode()
         except subprocess.CalledProcessError as e:
@@ -364,6 +369,13 @@ def job(t, args):
             logging.info(f"Target {result.args} failed with exit code {e.returncode}")
             sys.exit(1)
 
+    if using_libfuzzer:
+        print("Summary:")
+        max_len = max(len(t[0]) for t in stats)
+        for t, s in sorted(stats):
+            t = t.ljust(max_len + 1)
+            print(f"{t}{s}")
+
 
 def parse_test_list(*, fuzz_bin):
     test_list_all = subprocess.run(