[test] Add tests for _get_empty() funcs

test/test-blob.c

@@ -52,6 +52,7 @@ test_blob_empty (void)
 
   g_assert (hb_blob_is_immutable (hb_blob_get_empty ()));
   g_assert (hb_blob_get_empty () != NULL);
+  g_assert (hb_blob_get_empty () == hb_blob_create (NULL, 0, HB_MEMORY_MODE_READONLY, NULL, NULL));
 
   blob = hb_blob_get_empty ();
   g_assert (blob == hb_blob_get_empty ());

test/test-buffer.c

@@ -711,6 +711,12 @@ test_buffer_utf16_conversion (void)
   hb_buffer_destroy (b);
 }
 
+static void
+test_buffer_empty (void)
+{
+  g_assert (hb_buffer_get_empty ());
+  g_assert (hb_buffer_create (-1) == hb_buffer_get_empty ());
+}
 
 int
 main (int argc, char **argv)
@@ -734,6 +740,7 @@ main (int argc, char **argv)
   hb_test_add (test_buffer_utf8_conversion);
   hb_test_add (test_buffer_utf8_validity);
   hb_test_add (test_buffer_utf16_conversion);
+  hb_test_add (test_buffer_empty);
 
   return hb_test_run();
 }

test/test-unicode.c

@@ -550,6 +550,15 @@ test_unicode_properties_nil (void)
   hb_unicode_funcs_destroy (uf);
 }
 
+static void
+test_unicode_properties_empty (void)
+{
+  hb_unicode_funcs_t *uf = hb_unicode_funcs_get_empty ();
+
+  g_assert (hb_unicode_funcs_is_immutable (uf));
+  _test_unicode_properties_nil (uf);
+}
+
 
 static void
 test_unicode_chainup (void)
@@ -777,6 +786,7 @@ main (int argc, char **argv)
   hb_test_init (&argc, &argv);
 
   hb_test_add (test_unicode_properties_nil);
+  hb_test_add (test_unicode_properties_empty);
 
   hb_test_add_data_flavor (hb_unicode_funcs_get_default (),          "default", test_unicode_properties);
   hb_test_add_data_flavor ((gconstpointer) script_roundtrip_default, "default", test_unicode_script_roundtrip);