diff --git a/env.ps1 b/env.ps1
index 503c5b6..2de6034 100644
--- a/env.ps1
+++ b/env.ps1
@@ -41,7 +41,7 @@
 Function Global:dotest_ci { pytest -q -n auto --hypothesis-profile=ci }
 Function Global:dotest_long { pytest -q -n auto --hypothesis-profile=long }
 Function Global:docheck { dotidy; dolint; dotest }
-Function Global:_envps1_domut { mutmut run --paths-to-mutate "src/token.py,src/tokenize.py,src/parse.py" $args }
+Function Global:_envps1_domut { mutmut run --paths-to-mutate "src/token.py,src/tokenize.py,src/parse.py,src/i18n.py" $args }
 Function Global:domut { _envps1_domut }
 Function Global:domut_ci { _envps1_domut --no-progress || mutmut results }
 Function Global:dobuild { python build.py }
diff --git a/env.sh b/env.sh
index 1a677ba..35367a1 100644
--- a/env.sh
+++ b/env.sh
@@ -33,7 +33,7 @@
 dotest_ci() { pytest -q -n auto --hypothesis-profile=ci; }
 dotest_long() { pytest -q -n auto --hypothesis-profile=long; }
 docheck() { dotidy && dolint && dotest; }
-_envsh_domut() { mutmut run --paths-to-mutate "src/token.py,src/tokenize.py,src/parse.py" $@; }
+_envsh_domut() { mutmut run --paths-to-mutate "src/token.py,src/tokenize.py,src/parse.py,src/i18n.py" $@; }
 domut() { _envsh_domut; }
 domut_ci() { _envsh_domut --no-progress || (mutmut results; exit 1); }
 dobuild() { python build.py; }
diff --git a/src/i18n.py b/src/i18n.py
index 1b9baa0..0de3a8f 100644
--- a/src/i18n.py
+++ b/src/i18n.py
@@ -8,7 +8,7 @@
         self.values = values
 
     def __repr__(self):
-        return "Message('%s', %s)" % (self.id, self.values)
+        return "Message('%s', %s)" % (self.id, self.values)  # pragma: no mutate
 
     def __eq__(self, other):
         return self.id == other.id and self.values == other.values