tests FEATURE basic test of dictionary from hash_table.c
diff --git a/src/dict.h b/src/dict.h
index 2099012..35f9148 100644
--- a/src/dict.h
+++ b/src/dict.h
@@ -44,7 +44,7 @@
  * @param[in] len Number of bytes to store. The value is not required to be
  * NULL terminated string, the len parameter says number of bytes stored in
  * dictionary. The specified number of bytes is duplicated and terminating NULL
- * byte is added automatically.
+ * byte is added automatically. If \p len is 0, it is count automatically using strlen().
  * @return pointer to the string stored in the dictionary, NULL if \p value was NULL.
  */
 const char *lydict_insert(struct ly_ctx *ctx, const char *value, size_t len);
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5c6ccd4..ee34289 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -18,7 +18,8 @@
 add_subdirectory(src)
 
 foreach(test_name IN LISTS tests)
-    string(REGEX REPLACE "[a-z]*_" "" name "${test_name}")
+    message(STATUS ${test_name})
+    string(REGEX REPLACE "[a-z]*_(.*)" "\\1" name "${test_name}")
     string(REGEX REPLACE "([a-z]*)_.*" "\\1" prefix "${test_name}")
     add_executable(${test_name} ${prefix}/${name}.c)
 endforeach(test_name)
diff --git a/tests/src/CMakeLists.txt b/tests/src/CMakeLists.txt
index 505f52f..cf68357 100644
--- a/tests/src/CMakeLists.txt
+++ b/tests/src/CMakeLists.txt
@@ -1,10 +1,12 @@
 set(local_tests
     src_set
     src_common
-    src_context)
+    src_context
+    src_hash_table)
 set(local_tests_wraps
     " "
     "-Wl,--wrap=realloc"
-    "-Wl,--wrap=ly_set_add")
+    "-Wl,--wrap=ly_set_add"
+    " ")
 set(tests ${tests} ${local_tests} PARENT_SCOPE)
 set(tests_wraps ${tests_wraps} ${local_tests_wraps} PARENT_SCOPE)
diff --git a/tests/src/hash_table.c b/tests/src/hash_table.c
new file mode 100644
index 0000000..30017b8
--- /dev/null
+++ b/tests/src/hash_table.c
@@ -0,0 +1,131 @@
+/*
+ * @file hash_table.c
+ * @author: Radek Krejci <rkrejci@cesnet.cz>
+ * @brief unit tests for functions from hash_table.c
+ *
+ * Copyright (c) 2018 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 _BSD_SOURCE
+#define _DEFAULT_SOURCE
+
+#include "tests/config.h"
+#include "../../src/hash_table.c"
+
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include <string.h>
+#include <stdio.h>
+
+#include "libyang.h"
+
+#define BUFSIZE 1024
+char logbuf[BUFSIZE] = {0};
+
+/* set to 0 to printing error messages to stderr instead of checking them in code */
+#define ENABLE_LOGGER_CHECKING 1
+
+static void
+logger(LY_LOG_LEVEL level, const char *msg, const char *path)
+{
+    (void) level; /* unused */
+    (void) path; /* unused */
+
+    strncpy(logbuf, msg, BUFSIZE - 1);
+}
+
+static int
+logger_setup(void **state)
+{
+    (void) state; /* unused */
+#if ENABLE_LOGGER_CHECKING
+    ly_set_log_clb(logger, 0);
+#endif
+    return 0;
+}
+
+void
+logbuf_clean(void)
+{
+    logbuf[0] = '\0';
+}
+
+#if ENABLE_LOGGER_CHECKING
+#   define logbuf_assert(str) assert_string_equal(logbuf, str)
+#else
+#   define logbuf_assert(str)
+#endif
+
+static void
+test_invalid_arguments(void **state)
+{
+    (void) state; /* unused */
+    struct ly_ctx *ctx;
+
+    assert_int_equal(LY_SUCCESS, ly_ctx_new(NULL, 0, &ctx));
+
+    assert_null(lydict_insert(NULL, NULL, 0));
+    logbuf_assert("Invalid argument ctx (lydict_insert()).");
+
+    assert_null(lydict_insert_zc(NULL, NULL));
+    logbuf_assert("Invalid argument ctx (lydict_insert_zc()).");
+    logbuf_clean();
+    assert_null(lydict_insert_zc(ctx, NULL));
+    logbuf_assert("");
+
+    ly_ctx_destroy(ctx, NULL);
+}
+
+static void
+test_dict_hit(void **state)
+{
+    (void) state; /* unused */
+
+    const char *str1, *str2;
+    struct ly_ctx *ctx;
+
+    assert_int_equal(LY_SUCCESS, ly_ctx_new(NULL, 0, &ctx));
+
+    /* insert 2 strings, one of them repeatedly */
+    str1 = lydict_insert(ctx, "test1", 0);
+    assert_non_null(str1);
+    /* via zerocopy we have to get the same pointer as provided */
+    assert_non_null(str2 = strdup("test2"));
+    assert_true(str2 == lydict_insert_zc(ctx, (char *)str2));
+    /* here we get the same pointer as in case the string was inserted first time */
+    str2 = lydict_insert(ctx, "test1", 0);
+    assert_non_null(str2);
+    assert_ptr_equal(str1, str2);
+
+    /* remove strings, but the repeatedly inserted only once */
+    lydict_remove(ctx, "test1");
+    lydict_remove(ctx, "test2");
+
+    /* destroy dictionary - should raise warning about data presence */
+    ly_ctx_destroy(ctx, NULL);
+    logbuf_assert("String \"test1\" not freed from the dictionary, refcount 1");
+
+#ifndef NDEBUG
+    /* cleanup */
+    free((char*)str1);
+#endif
+}
+
+int main(void)
+{
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test_setup(test_invalid_arguments, logger_setup),
+        cmocka_unit_test_setup(test_dict_hit, logger_setup),
+    };
+
+    return cmocka_run_group_tests(tests, NULL, NULL);
+}