diff --git a/test/ranges-test.cc b/test/ranges-test.cc
index ff29171d..0ce88ba4 100644
--- a/test/ranges-test.cc
+++ b/test/ranges-test.cc
@@ -426,13 +426,6 @@ TEST(ranges_test, container_adaptor) {
     EXPECT_EQ(fmt::format("{}", s), "[1, 2]");
   }
 
-  {
-    std::stack<int, std::vector<int>> s;
-    s.push(1);
-    s.push(2);
-    EXPECT_EQ(fmt::format("{}", s), "[1, 2]");
-  }
-
   {
     std::queue<int> q;
     q.push(1);
@@ -449,6 +442,16 @@ TEST(ranges_test, container_adaptor) {
     EXPECT_EQ(fmt::format("{}", q), "[4, 3, 2, 1]");
   }
 
+  {
+    std::stack<char, std::string> s;
+    s.push('a');
+    s.push('b');
+    // Note: The output is formatted as a string because the underlying
+    // container is a string. This behavior is conforming to the standard
+    // [container.adaptors.format].
+    EXPECT_EQ(fmt::format("{}", s), "ab");
+  }
+
   {
     struct my_container_adaptor {
       using value_type = int;