1 files changed, 7 insertions, 6 deletions
diff --git a/ext/-test-/string/capacity.c b/ext/-test-/string/capacity.c
index ba7fb85e9e..33b2023fd3 100644
--- a/ext/-test-/string/capacity.c
+++ b/ext/-test-/string/capacity.c
@@ -1,17 +1,18 @@
 #include "ruby.h"
-#include "internal.h"
+#include "internal/string.h"
 
 static VALUE
 bug_str_capacity(VALUE klass, VALUE str)
 {
-    return
-	STR_EMBED_P(str) ? INT2FIX(RSTRING_EMBED_LEN_MAX) : \
-	STR_SHARED_P(str) ? INT2FIX(0) : \
-	LONG2FIX(RSTRING(str)->as.heap.aux.capa);
+    if (!STR_EMBED_P(str) && STR_SHARED_P(str)) {
+        return INT2FIX(0);
+    }
+
+    return LONG2FIX(rb_str_capacity(str));
 }
 
 void
-Init_capacity(VALUE klass)
+Init_string_capacity(VALUE klass)
 {
     rb_define_singleton_method(klass, "capacity", bug_str_capacity, 1);
 }