diff -r 6a842bd49fea -r 5ab3fe0b7859 tests/test_json.c
--- a/tests/test_json.c	Mon Dec 22 16:12:20 2025 +0100
+++ b/tests/test_json.c	Mon Dec 22 16:21:04 2025 +0100
@@ -1778,7 +1778,7 @@
     CX_TEST_ASSERT(result == 0);
 
     // compare the string
-    CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), expected));
+    CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), expected));
 
     // destroy everything
     cxBufferDestroy(&buf);
@@ -1919,7 +1919,7 @@
         CX_TEST_ASSERT(result == 0);
 
         // compare the string
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), expected));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), expected));
 
         // destroy everything
         cxBufferDestroy(&buf);
@@ -1938,45 +1938,45 @@
     CX_TEST_DO {
         // test default settings (6 digits)
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "3.141592"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "3.141592"));
 
         // test too many digits
         cxBufferReset(&buf);
         writer.frac_max_digits = 200;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "3.141592653589793"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "3.141592653589793"));
         
         // test 0 digits
         cxBufferReset(&buf);
         writer.frac_max_digits = 0;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "3"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "3"));
 
         // test 2 digits
         cxBufferReset(&buf);
         writer.frac_max_digits = 2;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "3.14"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "3.14"));
 
         // test 3 digits
         cxBufferReset(&buf);
         writer.frac_max_digits = 3;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "3.141"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "3.141"));
 
         // test 6 digits, but two are left of the decimal point
         num->number = 47.110815;
         cxBufferReset(&buf);
         writer.frac_max_digits = 6;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "47.110815"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "47.110815"));
 
         // test 4 digits with exponent
         num->number = 5.11223344e23;
         cxBufferReset(&buf);
         writer.frac_max_digits = 4;
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, num, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "5.1122e+23"));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "5.1122e+23"));
     }
     cxBufferDestroy(&buf);
     cxJsonValueFree(num);
@@ -2003,7 +2003,7 @@
     cxBufferInit(&buf, NULL, NULL, 128, 0);
     CX_TEST_DO {
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, str, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size),
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf),
             "\"hello\\twörld\\r\\nthis is\\\\a \\\"string\\\"\\b in \\u0007 string\\f\""));
     }
     cxBufferDestroy(&buf);
@@ -2019,7 +2019,7 @@
     cxBufferInit(&buf, NULL, NULL, 128, 0);
     CX_TEST_DO {
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, obj, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size),
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf),
             "{\"hello\\twörld\\r\\nthis is\\\\a \\\"string\\\"\\b in \\u0007 string\\f\":true}"));
     }
     cxBufferDestroy(&buf);
@@ -2034,13 +2034,13 @@
     CX_TEST_DO {
         // default: do not escape
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, str, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "\"test/solidus\""));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "\"test/solidus\""));
 
         // enable escaping
         writer.escape_slash = true;
         cxBufferReset(&buf);
         CX_TEST_ASSERT(0 == cxJsonWrite(&buf, str, cxBufferWriteFunc, &writer));
-        CX_TEST_ASSERT(0 == cx_strcmp(cx_strn(buf.space, buf.size), "\"test\\/solidus\""));
+        CX_TEST_ASSERT(0 == cx_strcmp(cx_bstr(&buf), "\"test\\/solidus\""));
     }
     cxBufferDestroy(&buf);
     cxJsonValueFree(str);