[tepl] File loading: write FileContent unit tests for the fallback mode

[Sébastien Wilmet <swilmet src gnome org>]

commit 4326a8f743a49aa7318b0a4db5c7bb4b017e54d4
Author: Sébastien Wilmet <swilmet gnome org>
Date:   Sun Oct 22 13:09:02 2017 +0200

    File loading: write FileContent unit tests for the fallback mode

 tepl/tepl-file-content.c      |   21 +++++----
 tepl/tepl-file-content.h      |    8 +++-
 testsuite/Makefile.am         |    3 +
 testsuite/test-file-content.c |  107 +++++++++++++++++++++++++++++++++++++++++
 4 files changed, 129 insertions(+), 10 deletions(-)
---
diff --git a/tepl/tepl-file-content.c b/tepl/tepl-file-content.c
index 66f8a43..d889607 100644
--- a/tepl/tepl-file-content.c
+++ b/tepl/tepl-file-content.c
@@ -164,14 +164,14 @@ determine_encoding_with_uchardet (TeplFileContent *content)
 /* Try the candidate encodings one by one, taking the first without conversion
  * error.
  */
-static TeplEncoding *
-determine_encoding_with_fallback_mode (TeplFileContent *content)
+TeplEncoding *
+_tepl_file_content_determine_encoding_with_fallback_mode (TeplFileContent *content,
+                                                         GSList          *candidate_encodings)
 {
-       GSList *candidate_encodings;
-       GSList *l;
        TeplEncoding *encoding = NULL;
+       GSList *l;
 
-       candidate_encodings = tepl_encoding_get_default_candidates ();
+       g_return_val_if_fail (TEPL_IS_FILE_CONTENT (content), NULL);
 
        for (l = candidate_encodings; l != NULL; l = l->next)
        {
@@ -184,8 +184,6 @@ determine_encoding_with_fallback_mode (TeplFileContent *content)
                }
        }
 
-       g_slist_free_full (candidate_encodings, (GDestroyNotify)tepl_encoding_free);
-
        return encoding;
 }
 
@@ -203,7 +201,12 @@ _tepl_file_content_determine_encoding (TeplFileContent *content)
 
        if (encoding == NULL)
        {
-               encoding = determine_encoding_with_fallback_mode (content);
+               GSList *candidate_encodings;
+
+               candidate_encodings = tepl_encoding_get_default_candidates ();
+               encoding = _tepl_file_content_determine_encoding_with_fallback_mode (content,
+                                                                                    candidate_encodings);
+               g_slist_free_full (candidate_encodings, (GDestroyNotify)tepl_encoding_free);
        }
 
        return encoding;
@@ -262,7 +265,7 @@ out:
        return success;
 }
 
-/* For the unit tests. */
+/* For unit tests. */
 gint64
 _tepl_file_content_get_encoding_converter_buffer_size (void)
 {
diff --git a/tepl/tepl-file-content.h b/tepl/tepl-file-content.h
index 9afa5f1..ec47cef 100644
--- a/tepl/tepl-file-content.h
+++ b/tepl/tepl-file-content.h
@@ -69,8 +69,14 @@ gboolean             _tepl_file_content_convert_to_utf8      (TeplFileContent              
   *c
                                                                 gpointer                         
callback_user_data,
                                                                 GError                         **error);
 
+/* For unit tests */
+
+G_GNUC_INTERNAL
+TeplEncoding *         _tepl_file_content_determine_encoding_with_fallback_mode        (TeplFileContent 
*content,
+                                                                                        GSList          
*candidate_encodings);
+
 G_GNUC_INTERNAL
-gint64                 _tepl_file_content_get_encoding_converter_buffer_size (void);
+gint64                 _tepl_file_content_get_encoding_converter_buffer_size           (void);
 
 G_END_DECLS
 
diff --git a/testsuite/Makefile.am b/testsuite/Makefile.am
index 1057c2d..d003894 100644
--- a/testsuite/Makefile.am
+++ b/testsuite/Makefile.am
@@ -52,6 +52,9 @@ test_encoding_converter_SOURCES = test-encoding-converter.c
 UNIT_TEST_PROGS += test-file
 test_file_SOURCES = test-file.c
 
+UNIT_TEST_PROGS += test-file-content
+test_file_content_SOURCES = test-file-content.c
+
 UNIT_TEST_PROGS += test-file-loader
 test_file_loader_SOURCES = test-file-loader.c
 
diff --git a/testsuite/test-file-content.c b/testsuite/test-file-content.c
new file mode 100644
index 0000000..db5e76d
--- /dev/null
+++ b/testsuite/test-file-content.c
@@ -0,0 +1,107 @@
+/*
+ * This file is part of Tepl, a text editor library.
+ *
+ * Copyright 2017 - Sébastien Wilmet <swilmet gnome org>
+ *
+ * Tepl is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; either version 2.1 of the License, or (at your
+ * option) any later version.
+ *
+ * Tepl is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
+ * License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <tepl/tepl.h>
+#include "tepl/tepl-file-content.h"
+#include <string.h>
+
+static void
+add_string (TeplFileContent *content,
+           const gchar     *str)
+{
+       GBytes *chunk;
+
+       chunk = g_bytes_new (str, strlen (str));
+       _tepl_file_content_add_chunk (content, chunk);
+       g_bytes_unref (chunk);
+}
+
+static void
+check_determine_encoding_fallback (GSList       *candidate_encodings,
+                                  const gchar  *str,
+                                  TeplEncoding *expected_encoding)
+{
+       TeplFileContent *content;
+       TeplEncoding *detected_encoding;
+
+       content = _tepl_file_content_new ();
+
+       if (str != NULL)
+       {
+               add_string (content, str);
+       }
+
+       detected_encoding = _tepl_file_content_determine_encoding_with_fallback_mode (content,
+                                                                                     candidate_encodings);
+
+       g_assert (tepl_encoding_equals (detected_encoding, expected_encoding));
+
+       g_object_unref (content);
+       tepl_encoding_free (detected_encoding);
+}
+
+static void
+test_determine_encoding_with_fallback_mode (void)
+{
+       GSList *candidate_encodings = NULL;
+       TeplEncoding *utf8_encoding;
+       TeplEncoding *ascii_encoding;
+
+       utf8_encoding = tepl_encoding_new_utf8 ();
+       ascii_encoding = tepl_encoding_new ("ASCII");
+
+       /* UTF-8 -> ASCII */
+       candidate_encodings = g_slist_append (candidate_encodings, utf8_encoding);
+       candidate_encodings = g_slist_append (candidate_encodings, ascii_encoding);
+
+       // An empty/0-bytes file has no GBytes chunks, the list is empty.
+       check_determine_encoding_fallback (candidate_encodings, NULL, utf8_encoding);
+
+       check_determine_encoding_fallback (candidate_encodings, "Wistiti", utf8_encoding);
+       check_determine_encoding_fallback (candidate_encodings, "Wißtiti", utf8_encoding);
+
+       g_slist_free (candidate_encodings);
+       candidate_encodings = NULL;
+
+       /* ASCII -> UTF-8 */
+       candidate_encodings = g_slist_append (candidate_encodings, ascii_encoding);
+       candidate_encodings = g_slist_append (candidate_encodings, utf8_encoding);
+
+       check_determine_encoding_fallback (candidate_encodings, NULL, ascii_encoding);
+       check_determine_encoding_fallback (candidate_encodings, "Wistiti", ascii_encoding);
+       check_determine_encoding_fallback (candidate_encodings, "Wißtiti", utf8_encoding);
+
+       g_slist_free (candidate_encodings);
+       candidate_encodings = NULL;
+
+       tepl_encoding_free (utf8_encoding);
+       tepl_encoding_free (ascii_encoding);
+}
+
+int
+main (int    argc,
+      char **argv)
+{
+       g_test_init (&argc, &argv, NULL);
+
+       g_test_add_func ("/FileContent/test_determine_encoding_with_fallback_mode",
+                        test_determine_encoding_with_fallback_mode);
+
+       return g_test_run ();
+}