diff -r 6cf10bb137c5 -r 4a08dabe5e8f tests/test_string.c
--- a/tests/test_string.c	Mon Dec 29 10:45:55 2025 +0100
+++ b/tests/test_string.c	Mon Dec 29 11:21:16 2025 +0100
@@ -835,24 +835,21 @@
 }
 
 CX_TEST(test_strtrim) {
-    cxstring t1 = cx_strtrim(cx_str("  ein test  \t "));
+    const char *t = "  ein test  \t ";
+    cxstring t1 = cx_strtrim(t);
     cxstring t2 = cx_strtrim(cx_str("abc"));
-    cxstring t3 = cx_strtrim(cx_str(" 123"));
-    cxstring t4 = cx_strtrim(cx_str("xyz "));
+    cxmutstr t3 = cx_strtrim(cx_mutstr((char*)" 123"));
+    cxmutstr t4 = cx_strtrim((char*)"xyz ");
     cxstring t5 = cx_strtrim(cx_str("   "));
     cxstring empty = cx_strtrim(cx_str(""));
 
     CX_TEST_DO {
-        CX_TEST_ASSERT(0 == cx_strcmp(t1, cx_str("ein test")));
-        CX_TEST_ASSERT(0 == cx_strcmp(t2, cx_str("abc")));
-        CX_TEST_ASSERT(0 == cx_strcmp(t3, cx_str("123")));
-        CX_TEST_ASSERT(0 == cx_strcmp(t4, cx_str("xyz")));
-        CX_TEST_ASSERT(0 == cx_strcmp(t5, cx_str("")));
-        CX_TEST_ASSERT(0 == cx_strcmp(empty, cx_str("")));
-
-        // call the _m variant just for coverage
-        cxmutstr m1 = cx_strtrim_m(cx_mutstr((char *) "  ein test  \t "));
-        CX_TEST_ASSERT(0 == cx_strcmp(m1, "ein test"));
+        CX_TEST_ASSERT(0 == cx_strcmp(t1, "ein test"));
+        CX_TEST_ASSERT(0 == cx_strcmp(t2, "abc"));
+        CX_TEST_ASSERT(0 == cx_strcmp(t3, "123"));
+        CX_TEST_ASSERT(0 == cx_strcmp(t4, "xyz"));
+        CX_TEST_ASSERT(0 == cx_strcmp(t5, ""));
+        CX_TEST_ASSERT(0 == cx_strcmp(empty, ""));
     }
 }