diff --git a/tests/utests/data/test_parser_xml.c b/tests/utests/data/test_parser_xml.c
index e0357d7..a40fdf5 100644
--- a/tests/utests/data/test_parser_xml.c
+++ b/tests/utests/data/test_parser_xml.c
@@ -175,6 +175,9 @@
     char *str;
     struct lyd_node *tree;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     data =
     "<any xmlns=\"urn:tests:a\">"
         "<element1>"
@@ -187,7 +190,7 @@
     assert_int_equal(LYS_ANYDATA, tree->schema->nodetype);
     assert_string_equal("any", tree->schema->name);
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str,
         "<any xmlns=\"urn:tests:a\">"
             "<element1>"
@@ -196,9 +199,11 @@
             "<element1a/>"
         "</any>"
     );
-    free(str);
+    lyp_out_reset(out);
 
     lyd_free_all(tree);
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
@@ -319,6 +324,9 @@
     char *str;
     struct lyd_node *tree;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     /* invalid value, no flags */
     data = "<foo3 xmlns=\"urn:tests:a\"/>";
     assert_int_equal(LY_EVALID, lyd_parse_xml_data(ctx, data, LYD_VALOPT_DATA_ONLY, &tree));
@@ -332,9 +340,9 @@
     assert_string_equal(((struct lyd_node_opaq *)tree)->name, "foo3");
     assert_string_equal(((struct lyd_node_opaq *)tree)->value, "");
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str, "<foo3 xmlns=\"urn:tests:a\"/>");
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* missing key, no flags */
@@ -350,9 +358,9 @@
     assert_string_equal(((struct lyd_node_opaq *)tree)->name, "l1");
     assert_string_equal(((struct lyd_node_opaq *)tree)->value, "");
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str, data);
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* invalid key, no flags */
@@ -368,9 +376,9 @@
     assert_string_equal(((struct lyd_node_opaq *)tree)->name, "l1");
     assert_string_equal(((struct lyd_node_opaq *)tree)->value, "");
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str, data);
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* opaq flag and fail */
@@ -378,6 +386,8 @@
             LYD_OPT_OPAQ | LYD_VALOPT_DATA_ONLY, &tree));
     assert_null(tree);
 
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
@@ -391,6 +401,9 @@
     struct lyd_node *tree, *op;
     const struct lyd_node *node;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     data =
         "<rpc xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\" msgid=\"25\" custom-attr=\"val\">"
             "<edit-config>"
@@ -434,7 +447,7 @@
     assert_null(node->schema);
     assert_string_equal(((struct lyd_node_opaq *)node)->name, "z");
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str,
         "<rpc xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\" msgid=\"25\" custom-attr=\"val\">"
             "<edit-config>"
@@ -453,12 +466,14 @@
                 "</config>"
             "</edit-config>"
         "</rpc>");
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* wrong namespace, element name, whatever... */
     /* TODO */
 
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
@@ -472,6 +487,9 @@
     struct lyd_node *tree, *op;
     const struct lyd_node *node;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     data =
         "<rpc xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\" msgid=\"25\" custom-attr=\"val\">"
             "<action xmlns=\"urn:ietf:params:xml:ns:yang:1\">"
@@ -496,7 +514,7 @@
     assert_string_equal(((struct lyd_node_opaq *)node)->name, "action");
     assert_null(((struct lyd_node_opaq *)node)->attr);
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str,
         "<rpc xmlns=\"urn:ietf:params:xml:ns:netconf:base:1.0\" msgid=\"25\" custom-attr=\"val\">"
             "<action xmlns=\"urn:ietf:params:xml:ns:yang:1\">"
@@ -507,12 +525,14 @@
                 "</c>"
             "</action>"
         "</rpc>");
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* wrong namespace, element name, whatever... */
     /* TODO */
 
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
@@ -526,6 +546,9 @@
     struct lyd_node *tree, *ntf;
     const struct lyd_node *node;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     data =
         "<notification xmlns=\"urn:ietf:params:xml:ns:netconf:notification:1.0\">"
             "<eventTime>2037-07-08T00:01:00Z</eventTime>"
@@ -553,9 +576,9 @@
     assert_non_null(node->schema);
     assert_string_equal(node->schema->name, "c");
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str, data);
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* top-level notif without envelope */
@@ -568,14 +591,16 @@
     assert_non_null(tree);
     assert_ptr_equal(ntf, tree);
 
-    lyd_print_mem(&str, tree, LYD_XML, 0);
+    lyd_print(out, tree, LYD_XML, 0);
     assert_string_equal(str, data);
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* wrong namespace, element name, whatever... */
     /* TODO */
 
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
@@ -589,6 +614,9 @@
     struct lyd_node *request, *tree, *op;
     const struct lyd_node *node;
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     data =
         "<c xmlns=\"urn:tests:a\">"
             "<act>"
@@ -619,15 +647,17 @@
     assert_string_equal(node->schema->name, "c");
 
     /* TODO print only rpc-reply node and then output subtree */
-    lyd_print_mem(&str, lyd_node_children(op), LYD_XML, 0);
+    lyd_print(out, lyd_node_children(op), LYD_XML, 0);
     assert_string_equal(str,
         "<al xmlns=\"urn:tests:a\">25</al>");
-    free(str);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     /* wrong namespace, element name, whatever... */
     /* TODO */
 
+    lyp_free(out, NULL, 1);
+
     *state = NULL;
 }
 
diff --git a/tests/utests/data/test_printer_xml.c b/tests/utests/data/test_printer_xml.c
index f6cca7b..084ac2c 100644
--- a/tests/utests/data/test_printer_xml.c
+++ b/tests/utests/data/test_printer_xml.c
@@ -176,18 +176,20 @@
     const char *result;
     char *printed;
     ssize_t len;
+    struct lyp_out *out;
 
     s->func = test_leaf;
+    assert_non_null(out = lyp_new_memory(&printed, 0));
 
     data = "<int8 xmlns=\"urn:tests:types\">\n 15 \t\n  </int8>";
     result = "<int8 xmlns=\"urn:tests:types\">15</int8>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, result);
-    free(printed);
     lyd_free_all(tree);
 
+    lyp_free(out, NULL, 1);
     s->func = NULL;
 }
 
@@ -199,25 +201,27 @@
     const char *data;
     char *printed;
     ssize_t len;
+    struct lyp_out *out;
 
     s->func = test_anydata;
+    assert_non_null(out = lyp_new_memory(&printed, 0));
 
     data = "<any xmlns=\"urn:tests:types\"><somexml xmlns:x=\"url:x\" xmlns=\"example.com\"><x:x/></somexml></any>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     /* canonized */
     data = "<any xmlns=\"urn:tests:types\"><somexml xmlns=\"example.com\"><x xmlns=\"url:x\"/></somexml></any>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     data = "<any xmlns=\"urn:tests:types\"/>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
     lyd_free_all(tree);
 
     data =
@@ -236,7 +240,7 @@
     assert_string_equal(((struct lyd_node_any *)tree)->value.tree->schema->name, "cont");
     /* but its children not */
     assert_null(((struct lyd_node_inner *)(((struct lyd_node_any *)tree)->value.tree))->child->schema);
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     /* canonized */
     data =
@@ -249,9 +253,11 @@
             "</cont>"
         "</any>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
+
     lyd_free_all(tree);
 
+    lyp_free(out, NULL, 1);
     s->func = NULL;
 }
 
@@ -263,39 +269,42 @@
     const char *data;
     char *printed;
     ssize_t len;
+    struct lyp_out *out;
 
     s->func = test_defaults;
 
+    assert_non_null(out = lyp_new_memory(&printed, 0));
+
     /* standard default value */
     data = "<c xmlns=\"urn:defaults\">aa</c>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c><a xmlns=\"urn:defaults\" xmlns:d=\"urn:defaults\">/d:b</a>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c>"
         "<a xmlns=\"urn:defaults\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\""
         " ncwd:default=\"true\" xmlns:d=\"urn:defaults\">/d:b</a>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c>"
         "<a xmlns=\"urn:defaults\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\""
         " ncwd:default=\"true\" xmlns:d=\"urn:defaults\">/d:b</a>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
     lyd_free_all(tree);
 
@@ -303,25 +312,25 @@
     data = "<c xmlns=\"urn:defaults\">aa</c><a xmlns=\"urn:defaults\">/d:b</a>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
     lyd_free_all(tree);
 
@@ -329,34 +338,35 @@
     data = "<c xmlns=\"urn:defaults\">aa</c><a xmlns=\"urn:defaults\" xmlns:d=\"urn:defaults\">/d:b</a><b xmlns=\"urn:defaults\">val</b>";
     assert_non_null(tree = lyd_parse_mem(s->ctx, data, LYD_XML, LYD_VALOPT_DATA_ONLY));
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_TRIM)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c><b xmlns=\"urn:defaults\">val</b>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c><a xmlns=\"urn:defaults\" xmlns:d=\"urn:defaults\">/d:b</a><b xmlns=\"urn:defaults\">val</b>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_ALL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c>"
         "<a xmlns=\"urn:defaults\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\""
         " ncwd:default=\"true\" xmlns:d=\"urn:defaults\">/d:b</a>"
         "<b xmlns=\"urn:defaults\">val</b>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
-    assert_true((len = lyd_print_mem(&printed, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
+    assert_true((len = lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG)) >= 0);
     assert_int_equal(len, strlen(printed));
     data = "<c xmlns=\"urn:defaults\">aa</c><a xmlns=\"urn:defaults\" xmlns:d=\"urn:defaults\">/d:b</a><b xmlns=\"urn:defaults\">val</b>";
     assert_string_equal(printed, data);
-    free(printed);
+    lyp_out_reset(out);
 
     lyd_free_all(tree);
+    lyp_free(out, NULL, 1);
 
     s->func = NULL;
 }
@@ -374,23 +384,25 @@
     const char *reply, *result;
     char *printed;
     ssize_t len;
+    struct lyp_out *out;
 
     s->func = test_rpc;
+    assert_non_null(out = lyp_new_memory(&printed, 0));
 
     request = "<sum xmlns=\"urn:tests:types\"><x>10</x><y>20</y></sum>";
     reply = "<result xmlns=\"urn:tests:types\">30</result>";
     result = "<sum xmlns=\"urn:tests:types\"><result>30</result></sum>";
     assert_non_null(tree1 = lyd_parse_mem(s->ctx, request, LYD_XML, LYD_OPT_RPC, NULL));
-    assert_true((len = lyd_print_mem(&printed, tree1, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree1, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, request);
-    free(printed);
+    lyp_out_reset(out);
     assert_non_null(trees = lyd_trees_new(1, tree1));
     assert_non_null(tree2 = lyd_parse_mem(s->ctx, reply, LYD_XML, LYD_OPT_RPCREPLY, trees));
-    assert_true((len = lyd_print_mem(&printed, tree2, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree2, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, result);
-    free(printed);
+    lyp_out_reset(out);
     lyd_trees_free(trees, 0);
     lyd_free_all(tree1);
     lyd_free_all(tree2);
@@ -400,16 +412,16 @@
     reply = "";
     result = "<sum xmlns=\"urn:tests:types\"/>";
     assert_non_null(tree1 = lyd_parse_mem(s->ctx, request, LYD_XML, LYD_OPT_RPC, NULL));
-    assert_true((len = lyd_print_mem(&printed, tree1, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree1, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, request);
-    free(printed);
+    lyp_out_reset(out);
     assert_non_null(trees = lyd_trees_new(1, tree1));
     assert_non_null(tree2 = lyd_parse_mem(s->ctx, reply, LYD_XML, LYD_OPT_RPCREPLY, trees));
-    assert_true((len = lyd_print_mem(&printed, tree2, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree2, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, result);
-    free(printed);
+    lyp_out_reset(out);
     lyd_trees_free(trees, 0);
     lyd_free_all(tree1);
     lyd_free_all(tree2);
@@ -424,20 +436,21 @@
     reply = "<b xmlns=\"urn:tests:types\">test-reply</b>";
     result = "<cont xmlns=\"urn:tests:types\"><listtarget><id>10</id><test><b>test-reply</b></test></listtarget></cont>";;
     assert_non_null(tree1 = lyd_parse_mem(s->ctx, request, LYD_XML, LYD_OPT_RPC, NULL));
-    assert_true((len = lyd_print_mem(&printed, tree1, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree1, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, request);
-    free(printed);
+    lyp_out_reset(out);
     assert_non_null(trees = lyd_trees_new(1, tree1));
     assert_non_null(tree2 = lyd_parse_mem(s->ctx, reply, LYD_XML, LYD_OPT_RPCREPLY, trees));
-    assert_true((len = lyd_print_mem(&printed, tree2, LYD_XML, 0)) >= 0);
+    assert_true((len = lyd_print(out, tree2, LYD_XML, 0)) >= 0);
     assert_int_equal(len, strlen(printed));
     assert_string_equal(printed, result);
-    free(printed);
+    lyp_out_reset(out);
     lyd_trees_free(trees, 0);
     lyd_free_all(tree1);
     lyd_free_all(tree2);
 
+    lyp_free(out, NULL, 1);
     s->func = NULL;
 }
 
diff --git a/tests/utests/data/test_validation.c b/tests/utests/data/test_validation.c
index 52d59ec..16d742a 100644
--- a/tests/utests/data/test_validation.c
+++ b/tests/utests/data/test_validation.c
@@ -1019,13 +1019,16 @@
     struct lyd_node *tree, *node;
     const struct lys_module *mod = ly_ctx_get_module_latest(ctx, "f");
 
+    struct lyp_out *out;
+    assert_non_null(out = lyp_new_memory(&str, 0));
+
     /* get defaults */
     tree = NULL;
     assert_int_equal(lyd_validate_modules(&tree, &mod, 1, 0), LY_SUCCESS);
     assert_non_null(tree);
 
     /* check all defaults exist */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<ll1 xmlns=\"urn:tests:f\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">def1</ll1>"
         "<ll1 xmlns=\"urn:tests:f\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">def2</ll1>"
@@ -1041,7 +1044,7 @@
             "<ll2 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">dflt1</ll2>"
             "<ll2 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">dflt2</ll2>"
         "</cont>");
-    free(str);
+    lyp_out_reset(out);
 
     /* create another explicit case and validate */
     node = lyd_new_term(NULL, mod, "l", "value");
@@ -1050,7 +1053,7 @@
     assert_int_equal(lyd_validate(&tree, ctx, LYD_VALOPT_DATA_ONLY), LY_SUCCESS);
 
     /* check data tree */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<d xmlns=\"urn:tests:f\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">15</d>"
         "<ll2 xmlns=\"urn:tests:f\" xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">dflt1</ll2>"
@@ -1064,7 +1067,7 @@
             "<ll2 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">dflt2</ll2>"
         "</cont>"
         "<l xmlns=\"urn:tests:f\">value</l>");
-    free(str);
+    lyp_out_reset(out);
 
     /* create explicit leaf-list and leaf and validate */
     node = lyd_new_term(NULL, mod, "d", "15");
@@ -1076,7 +1079,7 @@
     assert_int_equal(lyd_validate(&tree, ctx, LYD_VALOPT_DATA_ONLY), LY_SUCCESS);
 
     /* check data tree */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<cont xmlns=\"urn:tests:f\">"
             "<ll1 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">def1</ll1>"
@@ -1089,7 +1092,7 @@
         "<l xmlns=\"urn:tests:f\">value</l>"
         "<d xmlns=\"urn:tests:f\">15</d>"
         "<ll2 xmlns=\"urn:tests:f\">dflt2</ll2>");
-    free(str);
+    lyp_out_reset(out);
 
     /* create first explicit container, which should become implicit */
     node = lyd_new_inner(NULL, mod, "cont");
@@ -1099,7 +1102,7 @@
     assert_int_equal(lyd_validate(&tree, ctx, LYD_VALOPT_DATA_ONLY), LY_SUCCESS);
 
     /* check data tree */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<cont xmlns=\"urn:tests:f\">"
             "<ll1 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">def1</ll1>"
@@ -1112,7 +1115,7 @@
         "<l xmlns=\"urn:tests:f\">value</l>"
         "<d xmlns=\"urn:tests:f\">15</d>"
         "<ll2 xmlns=\"urn:tests:f\">dflt2</ll2>");
-    free(str);
+    lyp_out_reset(out);
 
     /* create second explicit container, which should become implicit, so the first tree node should be removed */
     node = lyd_new_inner(NULL, mod, "cont");
@@ -1121,7 +1124,7 @@
     assert_int_equal(lyd_validate(&tree, ctx, LYD_VALOPT_DATA_ONLY), LY_SUCCESS);
 
     /* check data tree */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<cont xmlns=\"urn:tests:f\">"
             "<ll1 xmlns:ncwd=\"urn:ietf:params:xml:ns:yang:ietf-netconf-with-defaults\" ncwd:default=\"true\">def1</ll1>"
@@ -1134,7 +1137,7 @@
         "<l xmlns=\"urn:tests:f\">value</l>"
         "<d xmlns=\"urn:tests:f\">15</d>"
         "<ll2 xmlns=\"urn:tests:f\">dflt2</ll2>");
-    free(str);
+    lyp_out_reset(out);
 
     /* similar changes for nested defaults */
     assert_non_null(lyd_new_term(tree, NULL, "ll1", "def3"));
@@ -1143,7 +1146,7 @@
     assert_int_equal(lyd_validate(&tree, ctx, LYD_VALOPT_DATA_ONLY), LY_SUCCESS);
 
     /* check data tree */
-    lyd_print_mem(&str, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
+    lyd_print(out, tree, LYD_XML, LYDP_WITHSIBLINGS | LYDP_WD_IMPL_TAG);
     assert_string_equal(str,
         "<cont xmlns=\"urn:tests:f\">"
             "<ll1>def3</ll1>"
@@ -1153,9 +1156,10 @@
         "<l xmlns=\"urn:tests:f\">value</l>"
         "<d xmlns=\"urn:tests:f\">15</d>"
         "<ll2 xmlns=\"urn:tests:f\">dflt2</ll2>");
-    free(str);
+    lyp_out_reset(out);
 
     lyd_free_siblings(tree);
+    lyp_free(out, NULL, 1);
 
     *state = NULL;
 }
diff --git a/tests/utests/schema/test_printer_yang.c b/tests/utests/schema/test_printer_yang.c
index 1f3f749..93e3aeb 100644
--- a/tests/utests/schema/test_printer_yang.c
+++ b/tests/utests/schema/test_printer_yang.c
@@ -131,16 +131,19 @@
             "    \"some reference\";\n"
             "}\n";
     char *printed;
+    struct lyp_out *out;
+    size_t size = 0;
 
+    assert_non_null(out = lyp_new_memory(&printed, 0));
     assert_int_equal(LY_SUCCESS, ly_ctx_new(NULL, 0, &ctx));
 
     assert_non_null(mod = lys_parse_mem(ctx, orig, LYS_IN_YANG));
-    assert_int_equal(strlen(orig), lys_print_mem(&printed, mod, LYS_OUT_YANG, 0, 0));
+    assert_int_equal(strlen(orig), size = lys_print(out, mod, LYS_OUT_YANG, 0, 0));
     assert_string_equal(printed, orig);
-    free(printed);
-    assert_int_equal(strlen(compiled), lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0, 0));
+    lyp_out_reset(out);
+    assert_int_equal(strlen(compiled), lys_print(out, mod, LYS_OUT_YANG_COMPILED, 0, 0));
     assert_string_equal(printed, compiled);
-    free(printed);
+    lyp_out_reset(out);
 
     orig = "module b {\n"
             "  yang-version 1.1;\n"
@@ -184,12 +187,12 @@
             "  }\n"
             "}\n";
     assert_non_null(mod = lys_parse_mem(ctx, orig, LYS_IN_YANG));
-    assert_int_equal(strlen(orig), lys_print_mem(&printed, mod, LYS_OUT_YANG, 0, 0));
+    assert_int_equal(strlen(orig), lys_print(out, mod, LYS_OUT_YANG, 0, 0));
     assert_string_equal(printed, orig);
-    free(printed);
-    assert_int_equal(strlen(compiled), lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0, 0));
+    lyp_out_reset(out);
+    assert_int_equal(strlen(compiled), lys_print(out, mod, LYS_OUT_YANG_COMPILED, 0, 0));
     assert_string_equal(printed, compiled);
-    free(printed);
+    lyp_out_reset(out);
 
     orig = compiled ="module c {\n"
             "  yang-version 1.1;\n"
@@ -209,14 +212,15 @@
             "  }\n"
             "}\n";
     assert_non_null(mod = lys_parse_mem(ctx, orig, LYS_IN_YANG));
-    assert_int_equal(strlen(orig), lys_print_mem(&printed, mod, LYS_OUT_YANG, 0, 0));
+    assert_int_equal(strlen(orig), lys_print(out, mod, LYS_OUT_YANG, 0, 0));
     assert_string_equal(printed, orig);
-    free(printed);
-    assert_int_equal(strlen(compiled), lys_print_mem(&printed, mod, LYS_OUT_YANG, 0, 0));
+    lyp_out_reset(out);
+    assert_int_equal(strlen(compiled), lys_print(out, mod, LYS_OUT_YANG, 0, 0));
     assert_string_equal(printed, compiled);
-    free(printed);
+    /* missing free(printed); which is done in the following lyp_free() */
 
     *state = NULL;
+    lyp_free(out, NULL, 1);
     ly_ctx_destroy(ctx, NULL);
 }
 
diff --git a/tests/utests/schema/test_printer_yin.c b/tests/utests/schema/test_printer_yin.c
index 2ffa611..5656795 100644
--- a/tests/utests/schema/test_printer_yin.c
+++ b/tests/utests/schema/test_printer_yin.c
@@ -578,20 +578,27 @@
             "  </rpc>\n"
             "</module>\n";
 
-    char * printed;
+    char *printed;
+    struct lyp_out *out;
+
+    assert_non_null(out = lyp_new_memory(&printed, 0));
     assert_int_equal(LY_SUCCESS, ly_ctx_new(NULL, 0, &ctx));
 
     assert_non_null(mod = lys_parse_mem(ctx, orig, LYS_IN_YANG));
-    assert_int_equal(strlen(ori_res), lys_print_mem(&printed, mod, LYS_OUT_YIN, 0, 0));
+    assert_int_equal(strlen(ori_res), lys_print(out, mod, LYS_OUT_YIN, 0, 0));
     assert_string_equal(printed, ori_res);
-    free(printed);
+
     /*
+    lyp_memory_clean(out);
     assert_int_equal(strlen(compiled), lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0, 0));
     assert_string_equal(printed, compiled);
-    free(printed);
     */
 
+    /* note that the printed is freed here, so it must not be freed via lyp_free()! */
+    free(printed);
+
     *state = NULL;
+    lyp_free(out, NULL, 0);
     ly_ctx_destroy(ctx, NULL);
 }