diff -r 5136f2fc32ec -r 26500fc24058 tests/test_printf.c
--- a/tests/test_printf.c	Sat Jan 13 17:51:42 2024 +0100
+++ b/tests/test_printf.c	Sun Jan 14 13:13:12 2024 +0100
@@ -64,23 +64,25 @@
 }
 
 CX_TEST(test_bprintf_large_string) {
+    unsigned len = cx_printf_sbo_size;
     CxTestingAllocator talloc;
     cx_testing_allocator_init(&talloc);
     CxAllocator *alloc = &talloc.base;
-    char *aaa = malloc(512);
-    char *bbb = malloc(512);
-    char *expected = malloc(1040);
-    memset(aaa, 'a', 511);
-    aaa[511] = 0;
-    memset(bbb, 'b', 511);
-    bbb[511] = 0;
+    char *aaa = malloc(len);
+    char *bbb = malloc(len);
+    char *expected = malloc(2*len+16);
+    memset(aaa, 'a', len-1);
+    aaa[len-1] = 0;
+    memset(bbb, 'b', len-1);
+    bbb[len-1] = 0;
     sprintf(expected, "After %s comes %s.", aaa, bbb);
     CX_TEST_DO {
         CxBuffer buf;
         cxBufferInit(&buf, NULL, 64, alloc, CX_BUFFER_AUTO_EXTEND);
         size_t r = cx_bprintf(&buf, "After %s comes %s.", aaa, bbb);
-        CX_TEST_ASSERT(r == 1036);
-        CX_TEST_ASSERT(buf.size == 1036);
+        size_t er = 2*len-2+14;
+        CX_TEST_ASSERT(r == er);
+        CX_TEST_ASSERT(buf.size == er);
         cxBufferPut(&buf, 0);
         CX_TEST_ASSERT(0 == strcmp(expected, buf.space));
         cxBufferDestroy(&buf);
@@ -271,17 +273,18 @@
 }
 
 CX_TEST(test_asprintf_large_string) {
-    char *aaa = malloc(512);
-    char *bbb = malloc(512);
-    char *expected = malloc(1040);
-    memset(aaa, 'a', 511);
-    aaa[511] = 0;
-    memset(bbb, 'b', 511);
-    bbb[511] = 0;
+    unsigned len = cx_printf_sbo_size;
+    char *aaa = malloc(len);
+    char *bbb = malloc(len);
+    char *expected = malloc(2*len+16);
+    memset(aaa, 'a', len-1);
+    aaa[len-1] = 0;
+    memset(bbb, 'b', len-1);
+    bbb[len-1] = 0;
     sprintf(expected, "After %s comes %s.", aaa, bbb);
     CX_TEST_DO {
         cxmutstr r = cx_asprintf("After %s comes %s.", aaa, bbb);
-        CX_TEST_ASSERT(r.length == 1036);
+        CX_TEST_ASSERT(r.length == 2*len-2+14);
         ASSERT_ZERO_TERMINATED(r);
         CX_TEST_ASSERT(0 == strcmp(r.ptr, expected));
         cx_strfree(&r);