tests FEATURE new tests for functions in common.c
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 5cd8733..9b0c74d 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -15,6 +15,7 @@
 include_directories(SYSTEM ${CMOCKA_INCLUDE_DIR})
 
 set(tests)
+set(tests_wraps)
 add_subdirectory(src)
 
 foreach(test_name IN LISTS tests)
@@ -26,6 +27,9 @@
 # Set common attributes of all tests
 foreach(test_name IN LISTS tests)
     target_link_libraries(${test_name} ${CMOCKA_LIBRARIES} yang)
+    list(GET tests_wraps 0 test_wrap)
+    set_target_properties(${test_name} PROPERTIES LINK_FLAGS "${test_wrap}")
+    list(REMOVE_AT tests_wraps 0)
     add_test(NAME ${test_name} COMMAND ${test_name})
 #    set_property(TEST ${test_name} PROPERTY ENVIRONMENT "LIBYANG_EXTENSIONS_PLUGINS_DIR=${CMAKE_BINARY_DIR}/src/extensions")
 #    set_property(TEST ${test_name} APPEND PROPERTY ENVIRONMENT "LIBYANG_USER_TYPES_PLUGINS_DIR=${CMAKE_BINARY_DIR}/src/user_types")
diff --git a/tests/src/CMakeLists.txt b/tests/src/CMakeLists.txt
index 56eefd6..a45966c 100644
--- a/tests/src/CMakeLists.txt
+++ b/tests/src/CMakeLists.txt
@@ -1,2 +1,8 @@
-set(local_tests src_set)
+set(local_tests
+    src_set
+    src_common)
+set(local_tests_wraps
+    " "
+    "-Wl,--wrap=realloc")
 set(tests ${tests} ${local_tests} PARENT_SCOPE)
+set(tests_wraps ${tests_wraps} ${local_tests_wraps} PARENT_SCOPE)
diff --git a/tests/src/common.c b/tests/src/common.c
new file mode 100644
index 0000000..2723e69
--- /dev/null
+++ b/tests/src/common.c
@@ -0,0 +1,118 @@
+/*
+ * @file set.c
+ * @author: Radek Krejci <rkrejci@cesnet.cz>
+ * @brief unit tests for functions from common.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
+ */
+
+#include "../../src/common.c"
+
+#define _BSD_SOURCE
+#define _DEFAULT_SOURCE
+#include <stdarg.h>
+#include <stddef.h>
+#include <setjmp.h>
+#include <cmocka.h>
+
+#include "libyang.h"
+
+#define BUFSIZE 1024
+char logbuf[BUFSIZE] = {0};
+
+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 */
+
+    ly_set_log_clb(logger, 0);
+
+    return 0;
+}
+
+static void
+test_date(void **state)
+{
+    (void) state; /* unused */
+
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, NULL, 0, "date"));
+    assert_string_equal(logbuf, "Invalid argument date (lysp_check_date()).");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "x", 1, "date"));
+    assert_string_equal(logbuf, "Invalid argument date_len (lysp_check_date()).");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "nonsencexx", 10, "date"));
+    assert_string_equal(logbuf, "Invalid value \"nonsencexx\" of \"date\".");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "123x-11-11", 10, "date"));
+    assert_string_equal(logbuf, "Invalid value \"123x-11-11\" of \"date\".");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "2018-13-11", 10, "date"));
+    assert_string_equal(logbuf, "Invalid value \"2018-13-11\" of \"date\".");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "2018-11-41", 10, "date"));
+    assert_string_equal(logbuf, "Invalid value \"2018-11-41\" of \"date\".");
+    assert_int_equal(LY_EINVAL, lysp_check_date(NULL, "2018-02-29", 10, "date"));
+    assert_string_equal(logbuf, "Invalid value \"2018-02-29\" of \"date\".");
+
+    assert_int_equal(LY_SUCCESS, lysp_check_date(NULL, "2018-11-11", 10, "date"));
+    assert_int_equal(LY_SUCCESS, lysp_check_date(NULL, "2018-02-28", 10, "date"));
+    assert_int_equal(LY_SUCCESS, lysp_check_date(NULL, "2016-02-29", 10, "date"));
+}
+
+void *__real_realloc(void *ptr, size_t size);
+void *__wrap_realloc(void *ptr, size_t size)
+{
+    int wrap = mock_type(int);
+
+    if (wrap) {
+        /* memory allocation failed */
+        return NULL;
+    } else {
+        return __real_realloc(ptr, size);
+    }
+}
+
+static void
+test_lyrealloc(void **state)
+{
+    (void) state; /* unused */
+
+    char *ptr;
+
+    ptr = malloc(1);
+    assert_non_null(ptr);
+
+    /* realloc */
+    will_return(__wrap_realloc, 0);
+    ptr = ly_realloc(ptr, 2048);
+    assert_non_null(ptr);
+    ptr[2047] = 0; /* test write */
+
+    /* realloc fails */
+    will_return(__wrap_realloc, 1);
+    ptr = ly_realloc(ptr, 2048);
+    assert_null(ptr);
+
+    /* ptr should be freed by ly_realloc() */
+}
+
+int main(void)
+{
+    const struct CMUnitTest tests[] = {
+        cmocka_unit_test_setup(test_date, logger_setup),
+        cmocka_unit_test(test_lyrealloc),
+    };
+
+    return cmocka_run_group_tests(tests, NULL, NULL);
+}