diff --git a/tests/qemucapsprobe.c b/tests/qemucapsprobe.c
index 6837f2a0f652d5061eb71c49b4a6ca8ef1c50c16..c7e8f3309d810578d25ba0d0121ddc4f438701d2 100644
--- a/tests/qemucapsprobe.c
+++ b/tests/qemucapsprobe.c
@@ -46,8 +46,14 @@ main(int argc, char **argv)
 {
     virThread thread;
     virQEMUCapsPtr caps;
+    const char *mock = VIR_TEST_MOCK("qemucapsprobe");
 
-    VIR_TEST_PRELOAD(VIR_TEST_MOCK("qemucapsprobe"));
+    if (!virFileIsExecutable(mock)) {
+        perror(mock);
+        return EXIT_FAILURE;
+    }
+
+    VIR_TEST_PRELOAD(mock);
 
     if (argc != 2) {
         fprintf(stderr, "%s QEMU_binary\n", argv[0]);
diff --git a/tests/testutils.c b/tests/testutils.c
index 6f0ef2b2f19b339a5890368a9785f379d4457e2f..b490609e363315c4b743aece9725a9c33c6b3e6f 100644
--- a/tests/testutils.c
+++ b/tests/testutils.c
@@ -856,15 +856,34 @@ int virTestMain(int argc,
     virLogOutputPtr *outputs = NULL;
     g_autofree char *baseprogname = NULL;
     const char *progname;
-
-    if (getenv("VIR_TEST_FILE_ACCESS"))
-        VIR_TEST_PRELOAD(VIR_TEST_MOCK("virtest"));
+    g_autofree const char **preloads = NULL;
+    size_t npreloads = 0;
+    g_autofree char *mock = NULL;
+
+    if (getenv("VIR_TEST_FILE_ACCESS")) {
+        preloads = g_renew(const char *, preloads, npreloads + 2);
+        preloads[npreloads++] = VIR_TEST_MOCK("virtest");
+        preloads[npreloads] = NULL;
+    }
 
     va_start(ap, func);
-    while ((lib = va_arg(ap, const char *)))
-        VIR_TEST_PRELOAD(lib);
+    while ((lib = va_arg(ap, const char *))) {
+        if (!virFileIsExecutable(lib)) {
+            perror(lib);
+            return EXIT_FAILURE;
+        }
+
+        preloads = g_renew(const char *, preloads, npreloads + 2);
+        preloads[npreloads++] = lib;
+        preloads[npreloads] = NULL;
+    }
     va_end(ap);
 
+    if (preloads) {
+        mock = g_strjoinv(":", (char **)preloads);
+        VIR_TEST_PRELOAD(mock);
+    }
+
     progname = baseprogname = g_path_get_basename(argv[0]);
     if (STRPREFIX(progname, "lt-"))
         progname += 3;
diff --git a/tests/testutils.h b/tests/testutils.h
index 8a7ea38f439b79dab0fdcd15819eeb8dd19a93bb..ad62dfb6470560c2437b8d44e2dada5ded4fb50e 100644
--- a/tests/testutils.h
+++ b/tests/testutils.h
@@ -127,19 +127,15 @@ int virTestMain(int argc,
 # define MOCK_EXT ".so"
 #endif
 
-#define VIR_TEST_PRELOAD(lib) \
+#define VIR_TEST_PRELOAD(libs) \
     do { \
         const char *preload = getenv(PRELOAD_VAR); \
-        if (preload == NULL || strstr(preload, lib) == NULL) { \
+        if (preload == NULL || strstr(preload, libs) == NULL) { \
             char *newenv; \
-            if (!virFileIsExecutable(lib)) { \
-                perror(lib); \
-                return EXIT_FAILURE; \
-            } \
             if (!preload) { \
-                newenv = (char *) lib; \
+                newenv = (char *) libs; \
             } else { \
-                newenv = g_strdup_printf("%s:%s", lib, preload); \
+                newenv = g_strdup_printf("%s:%s", libs, preload); \
             } \
             g_setenv(PRELOAD_VAR, newenv, TRUE); \
             FORCE_FLAT_NAMESPACE \