Allow to specify a failure reason in xfail

You can now specify a reason in xfail. Basically any scalar value except
'false' or 'off' is interpreted as true.

doc/liblouis.texi

@@ -2039,8 +2039,17 @@ The valid additional options for a test are as follows:
 
 @table @samp
 @item xfail
-Whether a test is expected to fail. Valid options are @samp{true},
-@samp{Y}, @samp{Yes} or @samp{ON}. Anything else is considered false.
+Whether a test is expected to fail. If you expect a test to fail, set
+this to @samp{true}. If you prefer you can also specifiy a reason for
+the failure:
+
+@example
+  - [Hello, ⠨, @{xfail: Testcase is not complete@}]
+@end example
+
+If you expect a test case to pass then just don't mark it with
+@samp{xfail} or if you really have to, set @samp{xfail} to
+@samp{false} or @samp{off}.
 
 @item typeform
 The typeform used for a translation. The typeform is passed in the

tests/check_yaml.c

@@ -120,15 +120,14 @@ read_flags (yaml_parser_t *parser, int *direction, int *hyphenation) {
 int
 read_xfail (yaml_parser_t *parser) {
   yaml_event_t event;
-  int xfail = 0;
+  /* assume xfail true if there is an xfail key */
+  int xfail = 1;
   if (!yaml_parser_parse(parser, &event) ||
       (event.type != YAML_SCALAR_EVENT))
     yaml_error(YAML_SCALAR_EVENT, &event);
-  if (!strcmp(event.data.scalar.value, "Y") ||
-      !strcmp(event.data.scalar.value, "true") ||
-      !strcmp(event.data.scalar.value, "Yes") ||
-      !strcmp(event.data.scalar.value, "ON"))
-    xfail = 1;
+  if (!strcmp(event.data.scalar.value, "false") ||
+      !strcmp(event.data.scalar.value, "off"))
+    xfail = 0;
   yaml_event_delete(&event);
   return xfail;
 }

tests/en-GB-g2_harness.yaml

@@ -225,7 +225,7 @@ tests:
       # FIXME: the original json based test only specified one cursor
       # position to be tested. Since I don't know the expected result
       # I'm setting this test to xfail
-      xfail: true
+      xfail: Test incomplete
   - # An example to reproduce:
     # https://bugzilla.gnome.org/show_bug.cgi?id=651217 note that the
     # braille cursor is very squeued. computer cursor is at pos 13,
@@ -237,7 +237,7 @@ tests:
       # FIXME: the original json based test only specified one cursor
       # position to be tested. Since I don't know the expected result
       # I'm setting this test to xfail
-      xfail: true
+      xfail: Test incomplete
   - # this testcase tests cursor position when mode is 0. The word
     # about is contracted to ab. The user presses cursor routing 1 on
     # their display, which should land on letter b, but instead it