diff --git a/tests/locale_test.cpp b/tests/locale_test.cpp
index 7d063f9..325f6ce 100644
--- a/tests/locale_test.cpp
+++ b/tests/locale_test.cpp
@@ -48,8 +48,8 @@
 }
 
 TEST(locale, setlocale) {
-  EXPECT_STREQ("C", setlocale(LC_ALL, NULL));
-  EXPECT_STREQ("C", setlocale(LC_CTYPE, NULL));
+  EXPECT_STREQ("C.UTF-8", setlocale(LC_ALL, NULL));
+  EXPECT_STREQ("C.UTF-8", setlocale(LC_CTYPE, NULL));
 
   errno = 0;
   EXPECT_EQ(NULL, setlocale(-1, NULL));
@@ -105,3 +105,20 @@
 
   EXPECT_EQ(n, uselocale(NULL));
 }
+
+TEST(locale, mb_cur_max) {
+  // We can't reliably test the behavior with setlocale(3) or the behavior for
+  // initial program conditions because (unless we're the only test that was
+  // run), another test has almost certainly called uselocale(3) in this thread.
+  // See b/16685652.
+  locale_t cloc = newlocale(LC_ALL, "C", 0);
+  locale_t cloc_utf8 = newlocale(LC_ALL, "C.UTF-8", 0);
+
+  uselocale(cloc);
+  ASSERT_EQ(1U, MB_CUR_MAX);
+  uselocale(cloc_utf8);
+  ASSERT_EQ(4U, MB_CUR_MAX);
+
+  freelocale(cloc);
+  freelocale(cloc_utf8);
+}
diff --git a/tests/stdio_test.cpp b/tests/stdio_test.cpp
index 18dae9c..bb86509 100644
--- a/tests/stdio_test.cpp
+++ b/tests/stdio_test.cpp
@@ -427,6 +427,9 @@
 }
 
 TEST(stdio, snprintf_utf8_15439554) {
+  locale_t cloc = newlocale(LC_ALL, "C.UTF-8", 0);
+  uselocale(cloc);
+
   // http://b/15439554
   char buf[BUFSIZ];
 
@@ -442,6 +445,8 @@
   // 4-byte character.
   snprintf(buf, sizeof(buf), "%d\xf0\xa4\xad\xa2%d", 1, 2);
   EXPECT_STREQ("1𤭢2", buf);
+
+  freelocale(cloc);
 }
 
 TEST(stdio, fprintf_failures_7229520) {