diff --git a/ChangeLog.adoc b/ChangeLog.adoc
index 6147a6ce1..573850374 100644
--- a/ChangeLog.adoc
+++ b/ChangeLog.adoc
@@ -30,6 +30,10 @@ Bug fixes::
   * trigger: fix recursive calls to triggers using regex (issue #1546)
   * trigger: add `${tg_tags} !!- ,notify_none,` in conditions of default trigger "beep" (issue #1529)
 
+Tests::
+
+  * core: add tests on GUI line functions
+
 Build::
 
   * core: disable debug by default in autotools build
diff --git a/tests/unit/gui/test-gui-line.cpp b/tests/unit/gui/test-gui-line.cpp
index a7ed03f40..5be73a185 100644
--- a/tests/unit/gui/test-gui-line.cpp
+++ b/tests/unit/gui/test-gui-line.cpp
@@ -23,7 +23,9 @@
 
 extern "C"
 {
+#include <string.h>
 #include "src/core/wee-string.h"
+#include "src/gui/gui-filter.h"
 #include "src/gui/gui-line.h"
 }
 
@@ -39,12 +41,252 @@ TEST_GROUP(GuiLine)
 {
 };
 
+/*
+ * Tests functions:
+ *   gui_line_lines_alloc
+ *   gui_line_lines_free
+ */
+
+TEST(GuiLine, LinesAlloc)
+{
+    struct t_gui_lines *lines;
+
+    lines = gui_line_lines_alloc ();
+    CHECK(lines);
+    POINTERS_EQUAL(NULL, lines->first_line);
+    POINTERS_EQUAL(NULL, lines->last_line);
+    POINTERS_EQUAL(NULL, lines->last_read_line);
+    LONGS_EQUAL(0, lines->lines_count);
+    LONGS_EQUAL(0, lines->first_line_not_read);
+    LONGS_EQUAL(0, lines->lines_hidden);
+    LONGS_EQUAL(0, lines->buffer_max_length);
+    LONGS_EQUAL(0, lines->buffer_max_length_refresh);
+    LONGS_EQUAL(0, lines->prefix_max_length);
+    LONGS_EQUAL(0, lines->prefix_max_length_refresh);
+
+    gui_line_lines_free (lines);
+
+    gui_line_lines_free (NULL);
+}
+
+/*
+ * Tests functions:
+ *   gui_line_tags_alloc
+ *   gui_line_tags_free
+ */
+
+TEST(GuiLine, TagsAlloc)
+{
+    struct t_gui_line_data line_data;
+
+    memset (&line_data, 0, sizeof (line_data));
+
+    gui_line_tags_alloc (NULL, NULL);
+
+    line_data.tags_array = (char **)0x1;
+    line_data.tags_count = 1;
+    gui_line_tags_alloc (&line_data, NULL);
+    POINTERS_EQUAL(NULL, line_data.tags_array);
+    LONGS_EQUAL(0, line_data.tags_count);
+
+    line_data.tags_array = (char **)0x1;
+    line_data.tags_count = 1;
+    gui_line_tags_alloc (&line_data, "");
+    POINTERS_EQUAL(NULL, line_data.tags_array);
+    LONGS_EQUAL(0, line_data.tags_count);
+
+    line_data.tags_array = NULL;
+    line_data.tags_count = 0;
+    gui_line_tags_alloc (&line_data, "tag1");
+    CHECK(line_data.tags_array);
+    STRCMP_EQUAL("tag1", line_data.tags_array[0]);
+    POINTERS_EQUAL(NULL, line_data.tags_array[1]);
+    LONGS_EQUAL(1, line_data.tags_count);
+    gui_line_tags_free (&line_data);
+
+    line_data.tags_array = NULL;
+    line_data.tags_count = 0;
+    gui_line_tags_alloc (&line_data, "tag1,tag2");
+    CHECK(line_data.tags_array);
+    STRCMP_EQUAL("tag1", line_data.tags_array[0]);
+    STRCMP_EQUAL("tag2", line_data.tags_array[1]);
+    POINTERS_EQUAL(NULL, line_data.tags_array[2]);
+    LONGS_EQUAL(2, line_data.tags_count);
+    gui_line_tags_free (&line_data);
+
+    line_data.tags_array = NULL;
+    line_data.tags_count = 0;
+    gui_line_tags_alloc (&line_data, "tag1,tag2,tag3");
+    CHECK(line_data.tags_array);
+    STRCMP_EQUAL("tag1", line_data.tags_array[0]);
+    STRCMP_EQUAL("tag2", line_data.tags_array[1]);
+    STRCMP_EQUAL("tag3", line_data.tags_array[2]);
+    POINTERS_EQUAL(NULL, line_data.tags_array[3]);
+    LONGS_EQUAL(3, line_data.tags_count);
+    gui_line_tags_free (&line_data);
+
+    gui_line_tags_free (NULL);
+}
+
+/*
+ * Tests functions:
+ *   gui_line_prefix_is_same_nick
+ */
+
+TEST(GuiLine, PrefixIsSameNick)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_prefix_for_display
+ */
+
+TEST(GuiLine, GetPrefixForDisplay)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_align
+ */
+
+TEST(GuiLine, GetAlign)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_is_displayed
+ */
+
+TEST(GuiLine, IsDisplayed)
+{
+    struct t_gui_line line;
+    int old_gui_filters_enabled;
+
+    memset (&line, 0, sizeof (line));
+    line.data = (struct t_gui_line_data *)malloc (sizeof (struct t_gui_line_data));
+
+    LONGS_EQUAL(0, gui_line_is_displayed (NULL));
+
+    old_gui_filters_enabled = gui_filters_enabled;
+
+    /* filters NOT enabled: line is always displayed */
+    gui_filters_enabled = 0;
+    line.data->displayed = 0;
+    LONGS_EQUAL(1, gui_line_is_displayed (&line));
+    line.data->displayed = 1;
+    LONGS_EQUAL(1, gui_line_is_displayed (&line));
+
+    /* filters enabled: line is displayed only if displayed == 1 */
+    gui_filters_enabled = 1;
+    line.data->displayed = 0;
+    LONGS_EQUAL(0, gui_line_is_displayed (&line));
+    line.data->displayed = 1;
+    LONGS_EQUAL(1, gui_line_is_displayed (&line));
+
+    gui_filters_enabled = old_gui_filters_enabled;
+
+    free (line.data);
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_first_displayed
+ */
+
+TEST(GuiLine, GetFirstDisplayed)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_last_displayed
+ */
+
+TEST(GuiLine, GetLastDisplayed)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_prev_displayed
+ */
+
+TEST(GuiLine, GetPrevDisplayed)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_next_displayed
+ */
+
+TEST(GuiLine, GetNextDisplayed)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_search_text
+ */
+
+TEST(GuiLine, SearchText)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_match_regex
+ */
+
+TEST(GuiLine, MatchRegex)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_has_tag_no_filter
+ */
+
+TEST(GuiLine, HasTagNoFilter)
+{
+    struct t_gui_line_data line_data;
+
+    memset (&line_data, 0, sizeof (line_data));
+
+    LONGS_EQUAL(0, gui_line_has_tag_no_filter (NULL));
+    LONGS_EQUAL(0, gui_line_has_tag_no_filter (&line_data));
+
+    gui_line_tags_alloc (&line_data, "tag1,tag2");
+    LONGS_EQUAL(0, gui_line_has_tag_no_filter (&line_data));
+    gui_line_tags_free (&line_data);
+
+    gui_line_tags_alloc (&line_data, "tag1,no_filter");
+    LONGS_EQUAL(1, gui_line_has_tag_no_filter (&line_data));
+    gui_line_tags_free (&line_data);
+
+    gui_line_tags_alloc (&line_data, "tag1,no_filter,tag2");
+    LONGS_EQUAL(1, gui_line_has_tag_no_filter (&line_data));
+    gui_line_tags_free (&line_data);
+}
+
 /*
  * Tests functions:
  *   gui_line_match_tags
  */
 
-TEST(GuiLine, LineMatchTags)
+TEST(GuiLine, MatchTags)
 {
     struct t_gui_line_data line_data;
     char ***tags_array;
@@ -79,3 +321,325 @@ TEST(GuiLine, LineMatchTags)
     WEE_LINE_MATCH_TAGS(1, "irc_join,nick_test", "!irc_quit,!irc_302,!irc_notice");
     WEE_LINE_MATCH_TAGS(1, "irc_join,nick_test", "!irc_quit+!irc_302+!irc_notice");
 }
+
+/*
+ * Tests functions:
+ *   gui_line_search_tag_starting_with
+ */
+
+TEST(GuiLine, SearchTagStartingWith)
+{
+    struct t_gui_line line;
+
+    memset (&line, 0, sizeof (line));
+    line.data = (struct t_gui_line_data *)malloc (sizeof (struct t_gui_line_data));
+    gui_line_tags_alloc (line.data, NULL);
+
+    POINTERS_EQUAL(NULL, gui_line_search_tag_starting_with (NULL, NULL));
+    POINTERS_EQUAL(NULL, gui_line_search_tag_starting_with (NULL, "abc"));
+    POINTERS_EQUAL(NULL, gui_line_search_tag_starting_with (&line, NULL));
+
+    POINTERS_EQUAL(NULL, gui_line_search_tag_starting_with (&line, "abc"));
+
+    gui_line_tags_alloc (line.data, "tag1,word2,last3");
+
+    POINTERS_EQUAL(NULL, gui_line_search_tag_starting_with (&line, "abc"));
+    STRCMP_EQUAL("tag1", gui_line_search_tag_starting_with (&line, "t"));
+    STRCMP_EQUAL("tag1", gui_line_search_tag_starting_with (&line, "tag"));
+    STRCMP_EQUAL("word2", gui_line_search_tag_starting_with (&line, "w"));
+    STRCMP_EQUAL("word2", gui_line_search_tag_starting_with (&line, "word"));
+    STRCMP_EQUAL("last3", gui_line_search_tag_starting_with (&line, "l"));
+    STRCMP_EQUAL("last3", gui_line_search_tag_starting_with (&line, "last"));
+
+    gui_line_tags_free (line.data);
+
+    free (line.data);
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_nick_tag
+ */
+
+TEST(GuiLine, GetNickTag)
+{
+    struct t_gui_line line;
+
+    memset (&line, 0, sizeof (line));
+    line.data = (struct t_gui_line_data *)malloc (sizeof (struct t_gui_line_data));
+    gui_line_tags_alloc (line.data, NULL);
+
+    POINTERS_EQUAL(NULL, gui_line_get_nick_tag (NULL));
+
+    POINTERS_EQUAL(NULL, gui_line_get_nick_tag (&line));
+
+    gui_line_tags_alloc (line.data, "tag1,tag2,tag3");
+    POINTERS_EQUAL(NULL, gui_line_get_nick_tag (&line));
+    gui_line_tags_free (line.data);
+
+    gui_line_tags_alloc (line.data, "tag1,tag2,nick_jdoe,tag3");
+    STRCMP_EQUAL("jdoe", gui_line_get_nick_tag (&line));
+    gui_line_tags_free (line.data);
+
+    free (line.data);
+}
+
+/*
+ * Tests functions:
+ *   gui_line_has_highlight
+ */
+
+TEST(GuiLine, HasHighlight)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_has_offline_nick
+ */
+
+TEST(GuiLine, HasOfflineNick)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_compute_buffer_max_length
+ */
+
+TEST(GuiLine, ComputeBufferMaxLength)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_compute_prefix_max_length
+ */
+
+TEST(GuiLine, ComputePrefixMaxLength)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_add_to_list
+ */
+
+TEST(GuiLine, AddToList)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_free_data
+ */
+
+TEST(GuiLine, FreeData)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_remove_from_list
+ */
+
+TEST(GuiLine, RemoveFromList)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_mixed_add
+ */
+
+TEST(GuiLine, MixedAdd)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_mixed_free_buffer
+ */
+
+TEST(GuiLine, MixedFreeBuffer)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_mixed_free_all
+ */
+
+TEST(GuiLine, MixedFreeAll)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_free
+ */
+
+TEST(GuiLine, Free)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_free_all
+ */
+
+TEST(GuiLine, FreeAll)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_notify_level
+ */
+
+TEST(GuiLine, GetNotifyLevel)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_get_highlight
+ */
+
+TEST(GuiLine, GetHighlight)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_new
+ */
+
+TEST(GuiLine, New)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_hook_update
+ */
+
+TEST(GuiLine, HookUpdate)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_add
+ */
+
+TEST(GuiLine, Add)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_add_y
+ */
+
+TEST(GuiLine, AddY)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_clear
+ */
+
+TEST(GuiLine, Clear)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_mix_buffers
+ */
+
+TEST(GuiLine, MixBuffers)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_hdata_lines_cb
+ */
+
+TEST(GuiLine, HdataLinesCb)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_hdata_line_cb
+ */
+
+TEST(GuiLine, HdataLineCb)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_hdata_line_data_update_cb
+ */
+
+TEST(GuiLine, HdataLineDataUpdateCb)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_hdata_line_data_cb
+ */
+
+TEST(GuiLine, HdataLineDataCb)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_line_add_to_infolist
+ */
+
+TEST(GuiLine, AddToInfolist)
+{
+    /* TODO: write tests */
+}
+
+/*
+ * Tests functions:
+ *   gui_lines_print_log
+ */
+
+TEST(GuiLine, HdataPrintLog)
+{
+    /* TODO: write tests */
+}