diff --git a/src/libnm-glib-aux/tests/test-shared-general.c b/src/libnm-glib-aux/tests/test-shared-general.c
index 35d0d1a2e5..58ede68c78 100644
--- a/src/libnm-glib-aux/tests/test-shared-general.c
+++ b/src/libnm-glib-aux/tests/test-shared-general.c
@@ -1729,6 +1729,70 @@ test_unbase64mem2(void)
 
 /*****************************************************************************/
 
+static void
+_test_unbase64mem_mem(const char *base64, const guint8 *expected_arr, gsize expected_len)
+{
+    gs_free char        *expected_base64 = NULL;
+    int                  r;
+    nm_auto_free guint8 *exp2_arr = NULL;
+    nm_auto_free guint8 *exp3_arr = NULL;
+    gsize                exp2_len;
+    gsize                exp3_len;
+
+    expected_base64 = g_base64_encode(expected_arr, expected_len);
+
+    r = nm_unbase64mem_full(expected_base64, strlen(expected_base64), TRUE, &exp2_arr, &exp2_len);
+    g_assert_cmpint(r, ==, 0);
+    g_assert_cmpmem(expected_arr, expected_len, exp2_arr, exp2_len);
+
+    if (!nm_streq(base64, expected_base64)) {
+        r = nm_unbase64mem_full(base64, strlen(base64), TRUE, &exp3_arr, &exp3_len);
+        g_assert_cmpint(r, ==, 0);
+        g_assert_cmpmem(expected_arr, expected_len, exp3_arr, exp3_len);
+    }
+}
+
+#define _test_unbase64mem(base64, expected_str) \
+    _test_unbase64mem_mem(base64, (const guint8 *) "" expected_str "", NM_STRLEN(expected_str))
+
+static void
+_test_unbase64mem_inval(const char *base64)
+{
+    gs_free guint8 *exp_arr = NULL;
+    gsize           exp_len = 0;
+    int             r;
+
+    r = nm_unbase64mem_full(base64, strlen(base64), TRUE, &exp_arr, &exp_len);
+    g_assert_cmpint(r, <, 0);
+    g_assert(!exp_arr);
+    g_assert(exp_len == 0);
+}
+
+static void
+test_unbase64mem3(void)
+{
+    gs_free char *rnd_base64 = NULL;
+    guint8        rnd_buf[30];
+    guint         i, rnd_len;
+
+    _test_unbase64mem("", "");
+    _test_unbase64mem("  ", "");
+    _test_unbase64mem(" Y Q == ", "a");
+    _test_unbase64mem(" Y   WJjZGV mZ 2g = ", "abcdefgh");
+    _test_unbase64mem_inval(" Y   %WJjZGV mZ 2g = ");
+    _test_unbase64mem_inval(" Y   %WJjZGV mZ 2g = a");
+    _test_unbase64mem("YQ==", "a");
+    _test_unbase64mem_inval("YQ==a");
+
+    rnd_len = nmtst_get_rand_uint32() % sizeof(rnd_buf);
+    for (i = 0; i < rnd_len; i++)
+        rnd_buf[i] = nmtst_get_rand_uint32() % 256;
+    rnd_base64 = g_base64_encode(rnd_buf, rnd_len);
+    _test_unbase64mem_mem(rnd_base64, rnd_buf, rnd_len);
+}
+
+/*****************************************************************************/
+
 NMTST_DEFINE();
 
 int
@@ -1766,6 +1830,7 @@ main(int argc, char **argv)
     g_test_add_func("/general/test_unbase64char", test_unbase64char);
     g_test_add_func("/general/test_unbase64mem1", test_unbase64mem1);
     g_test_add_func("/general/test_unbase64mem2", test_unbase64mem2);
+    g_test_add_func("/general/test_unbase64mem3", test_unbase64mem3);
 
     return g_test_run();
 }