tests: bound generator subprocesses

tests/mkemoji_test.py

@@ -9,13 +9,16 @@ from pathlib import Path
 
 ROOT = Path(__file__).resolve().parents[1]
 MKEMOJI = ROOT / "map" / "mkemoji"
+TIMEOUT = 10
 
 
 def generate(source=None):
     args = [sys.executable, "-B", str(MKEMOJI)]
     if source is not None:
         args.append(str(source))
-    return subprocess.run(args, capture_output=True, text=True, check=False)
+    return subprocess.run(
+        args, capture_output=True, text=True, check=False, timeout=TIMEOUT
+    )
 
 
 def table(output):