diff --git a/tests/utests/CMakeLists.txt b/tests/utests/CMakeLists.txt
index 3c1e777..4e3543f 100644
--- a/tests/utests/CMakeLists.txt
+++ b/tests/utests/CMakeLists.txt
@@ -45,3 +45,4 @@
 
 ly_add_utest(NAME metadata SOURCES extensions/test_metadata.c)
 ly_add_utest(NAME nacm SOURCES extensions/test_nacm.c)
+ly_add_utest(NAME yangdata SOURCES extensions/test_yangdata.c)
diff --git a/tests/utests/extensions/test_yangdata.c b/tests/utests/extensions/test_yangdata.c
new file mode 100644
index 0000000..357dcab
--- /dev/null
+++ b/tests/utests/extensions/test_yangdata.c
@@ -0,0 +1,246 @@
+/*
+ * @file test_yangdata.c
+ * @author: Radek Krejci <rkrejci@cesnet.cz>
+ * @brief unit tests for yang-data extensions support
+ *
+ * Copyright (c) 2019-2021 CESNET, z.s.p.o.
+ *
+ * This source code is licensed under BSD 3-Clause License (the "License").
+ * You may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     https://opensource.org/licenses/BSD-3-Clause
+ */
+#define _UTEST_MAIN_
+#include "utests.h"
+
+#include "libyang.h"
+
+static int
+setup(void **state)
+{
+    UTEST_SETUP;
+
+    assert_int_equal(LY_SUCCESS, ly_ctx_set_searchdir(UTEST_LYCTX, TESTS_DIR_MODULES_YANG));
+    assert_non_null(ly_ctx_load_module(UTEST_LYCTX, "ietf-restconf", "2017-01-26", NULL));
+
+    return 0;
+}
+
+static void
+test_schema(void **state)
+{
+    const struct lys_module *mod;
+    struct lysc_ext_instance *e;
+    char *printed = NULL;
+    const char *data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "feature x;"
+            "rc:yang-data template { container x { list l { leaf x { type string;}} leaf y {if-feature x; type string; config false;}}}}";
+    const char *info = "module a {\n"
+            "  namespace \"urn:tests:extensions:yangdata:a\";\n"
+            "  prefix self;\n\n"
+            "  ietf-restconf:yang-data \"template\" {\n"
+            "    container x {\n"
+            "      status current;\n"
+            "      list l {\n" /* no key */
+            "        min-elements 0;\n"
+            "        max-elements 4294967295;\n"
+            "        ordered-by system;\n"
+            "        status current;\n"
+            "        leaf x {\n"
+            "          type string;\n"
+            "          status current;\n"
+            "        }\n"
+            "      }\n"
+            "      leaf y {\n" /* config and if-feature are ignored */
+            "        type string;\n"
+            "        status current;\n"
+            "      }\n"
+            "    }\n"
+            "  }\n"
+            "}\n";
+
+    /* valid data */
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, &mod));
+    assert_non_null(e = mod->compiled->exts);
+    assert_int_equal(LY_ARRAY_COUNT(mod->compiled->exts), 1);
+    assert_int_equal(LY_SUCCESS, lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0));
+    assert_string_equal(printed, info);
+    free(printed);
+
+    data = "module c {yang-version 1.1; namespace urn:tests:extensions:yangdata:c; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "grouping g { choice ch { container a {presence a; config false;} container b {presence b; config true;}}}"
+            "rc:yang-data template { uses g;}}";
+    info = "module c {\n"
+            "  namespace \"urn:tests:extensions:yangdata:c\";\n"
+            "  prefix self;\n\n"
+            "  ietf-restconf:yang-data \"template\" {\n"
+            "    choice ch {\n"
+            "      status current;\n"
+            "      case a {\n"
+            "        status current;\n"
+            "        container a {\n"
+            "          presence \"true\";\n"
+            "          status current;\n"
+            "        }\n"
+            "      }\n"
+            "      case b {\n"
+            "        status current;\n"
+            "        container b {\n"
+            "          presence \"true\";\n"
+            "          status current;\n"
+            "        }\n"
+            "      }\n"
+            "    }\n"
+            "  }\n"
+            "}\n";
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, &mod));
+    assert_non_null(e = mod->compiled->exts);
+    assert_int_equal(LY_ARRAY_COUNT(mod->compiled->exts), 1);
+    assert_int_equal(LY_SUCCESS, lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0));
+    assert_string_equal(printed, info);
+    free(printed);
+
+    /* ignored - valid with warning */
+    data = "module b {yang-version 1.1; namespace urn:tests:extensions:yangdata:b; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "container b { rc:yang-data template { container x { leaf x {type string;}}}}}";
+    info = "module b {\n"
+            "  namespace \"urn:tests:extensions:yangdata:b\";\n"
+            "  prefix self;\n"
+            "  container b {\n"
+            "    config true;\n"
+            "    status current;\n"
+            "  }\n"
+            "}\n";
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, &mod));
+    assert_null(mod->compiled->exts);
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is ignored since it appears as a non top-level statement in \"data node\" statement.",
+            "/b:b/{extension='rc:yang-data'}/template");
+    assert_int_equal(LY_SUCCESS, lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0));
+    assert_string_equal(printed, info);
+    free(printed);
+
+    /* sama data nodes name, but not conflicting */
+    data = "module d {yang-version 1.1; namespace urn:tests:extensions:yangdata:d; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "leaf d { type string;}"
+            "rc:yang-data template1 { container d {presence d;}}"
+            "rc:yang-data template2 { container d {presence d;}}}";
+    info = "module d {\n"
+            "  namespace \"urn:tests:extensions:yangdata:d\";\n"
+            "  prefix self;\n\n"
+            "  ietf-restconf:yang-data \"template1\" {\n"
+            "    container d {\n"
+            "      presence \"true\";\n"
+            "      status current;\n"
+            "    }\n"
+            "  }\n"
+            "  ietf-restconf:yang-data \"template2\" {\n"
+            "    container d {\n"
+            "      presence \"true\";\n"
+            "      status current;\n"
+            "    }\n"
+            "  }\n"
+            "  leaf d {\n"
+            "    type string;\n"
+            "    config true;\n"
+            "    status current;\n"
+            "  }\n"
+            "}\n";
+    assert_int_equal(LY_SUCCESS, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, &mod));
+    assert_non_null(e = mod->compiled->exts);
+    assert_int_equal(LY_ARRAY_COUNT(mod->compiled->exts), 2);
+    assert_int_equal(LY_SUCCESS, lys_print_mem(&printed, mod, LYS_OUT_YANG_COMPILED, 0));
+    assert_string_equal(printed, info);
+    free(printed);
+}
+
+static void
+test_schema_invalid(void **state)
+{
+    const char *data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template { leaf x {type string;}}}";
+
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Invalid keyword \"leaf\" as a child of \"rc:yang-data template\" extension instance.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template { choice x { leaf x {type string;}}}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated with leaf top level data node (inside a choice), "
+            "but only a single container data node is allowed.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template { choice x { case x { container z {presence ppp;} leaf x {type string;}}}}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated with multiple top level data nodes (inside a single choice's case), "
+            "but only a single container data node is allowed.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template { container x { leaf x {type string;}} container y { leaf y {type string;}}}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated with multiple top level data nodes, "
+            "but only a single container data node is allowed.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template;}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated without any top level data node, "
+            "but exactly one container data node is expected.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data { container x { leaf x {type string;}}}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated without mandatory argument representing YANG data template name.",
+            "/a:{extension='rc:yang-data'}");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "rc:yang-data template { container x { leaf x {type string;}}}"
+            "rc:yang-data template { container y { leaf y {type string;}}}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated multiple times.",
+            "/a:{extension='rc:yang-data'}/template");
+
+    data = "module a {yang-version 1.1; namespace urn:tests:extensions:yangdata:a; prefix self;"
+            "import ietf-restconf {revision-date 2017-01-26; prefix rc;}"
+            "grouping t { leaf-list x {type string;}}"
+            "rc:yang-data template { uses t;}}";
+    assert_int_equal(LY_EVALID, lys_parse_mem(UTEST_LYCTX, data, LYS_IN_YANG, NULL));
+    CHECK_LOG_CTX("Extension plugin \"libyang 2 - yang-data, version 1\": "
+            "Extension rc:yang-data is instantiated with leaf-list top level data node, "
+            "but only a single container data node is allowed.",
+            "/a:{extension='rc:yang-data'}/template");
+}
+
+int
+main(void)
+{
+    const struct CMUnitTest tests[] = {
+        UTEST(test_schema, setup),
+        UTEST(test_schema_invalid, setup),
+    };
+
+    return cmocka_run_group_tests(tests, NULL, NULL);
+}