Remove XFAIL_TESTS from Makefile.am

The variable XFAIL_TESTS is not used anymore since commit e90073f7dd.

The description for the known failures are moved into the respective tests as
comments.

The following descriptions were dropped:

- surface-pattern-big: Didn't really explain the failure
- big-line: Test isn't failing any more
- self-intersecting: Only XFAIL on quartz, but description doesn't match this

The following tests don't have a xfail reference image and seem to fail just
because of not having a reference image at all (I kept their description for
now):

big-trap, long-lines, self-copy-overlap

Signed-off-by: Uli Schlachter <psychon@znc.in>

test/Makefile.am

@@ -142,79 +142,6 @@ surface-source.c	\
 testtable.js		\
 reference
 
-# Any test for which the code committed to CVS is expected to fail
-# should be listed here.
-#
-# This way, we can avoid being bothered by reports of bugs we are
-# aware of, but users can still report when tests start behaving in
-# unexpected ways on their system.
-#
-# Of course, before any "release" of cairo we should eliminate
-# everything from this list by fixing the bugs. (We don't necessarily
-# have to be that strict for "snapshots" though.)
-#
-# Analysis of XFAIL errors:
-# alpha-similar         - discrepancy between backends in applying color
-#                         components of a pure alpha surface
-# big-line              - range overflow of fixed-point
-# big-trap              - range overflow of fixed-point
-# degenerate-dash       - needs path editing in PS to convert degenerate
-#                         end-caps into the shapes as expected by cairo
-#                         (Or maybe PS is the correct behaviour?)
-# degenerate-path       - undefined behaviour in PS, needs path editing to
-#                         convert degenerate segments into circles/rectangles
-#                         as expected by cairo
-# device-offset-scale   - complication of pre-multiplying device_offset
-#                         into the pattern_matrix and then requiring further
-#                         manipulation for SVG
-# extend-pad            - lacks implementation in pixman and consequently used
-#                         as an excuse for lack of support in other backends
-# fallback-resolution   - The essential problem here is that the recording-surface
-#                         has recorded a sequence of operations with one device
-#                         transformation, and we attempt to replay it with
-#                         another (basically a scale-factor for the falback
-#                         resolution). Carl begun to look at this with his
-#                         chain-of-bugs, but the can of worms is much bigger.
-#                         It appears to be a design flaw in the recording-surface
-#                         that may spread further...
-#                         My solution would be to lock Behad and Adrian in a
-#                         room, with Carl as a moderator and not let them out
-#                         until they have come up with an interface and
-#                         semantics that actually work. :-)
-# in-fill-empty-trapezoid The cairo_in_fill () function can sometimes
-#                         produce false positives when the tessellator
-#                         produces empty trapezoids and the query
-#                         point lands exactly on a trapezoid edge.
-# long-lines            - range overflow of fixed-point
-# scale-offset-image    - loss of precision converting a cairo matrix to
-# scale-offset-similar    pixman's fixed point format.
-# self-copy-overlap     - vector surfaces take snapshot of patterns in contrast
-#                         to the raster backends which don't. One solution
-#                         would be to clone overlapping areas of dst/source, so
-#                         patterns were effectively snapshotted across all
-#                         backends.
-# self-intersecting     - incremental trapezoidation of strokes can generate
-#                         overlapping traps. Needs self-intersection analysis
-#                         on cairo_traps_t after strokes.
-#                         Test case should also be expanded to hit special-case
-#                         tessellators as well.
-# surface-pattern-big...- Strange, unexplained results for SVG/PS.
-XFAIL_TESTS =					\
-alpha-similar$(EXEEXT)				\
-big-line$(EXEEXT)				\
-big-trap$(EXEEXT)				\
-degenerate-dash$(EXEEXT)			\
-degenerate-path$(EXEEXT)			\
-device-offset-scale$(EXEEXT)			\
-extend-pad$(EXEEXT)				\
-fallback-resolution$(EXEEXT)			\
-in-fill-empty-trapezoid$(EXEEXT)		\
-long-lines$(EXEEXT)				\
-self-copy-overlap$(EXEEXT)			\
-self-intersecting$(EXEEXT)			\
-surface-pattern-big-scale-down$(EXEEXT)		\
-$(NULL)
-
 # Any test that doesn't generate a log file goes here
 NOLOG_TESTS =			\
 fallback-resolution		\

test/alpha-similar.c

@@ -60,6 +60,10 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/*
+ * XFAIL: discrepancy between backends in applying color components of a pure
+ * alpha surface
+ */
 CAIRO_TEST (alpha_similar,
 	    "Tests creation of similar alpha surfaces"
 	    "\nApplication of a pure-alpha similar source is inconsistent across backends.",

test/big-trap.c

@@ -82,6 +82,7 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/* XFAIL: range overflow of fixed-point */
 CAIRO_TEST (big_trap,
 	    "Test oversize trapezoid with a clip region"
 	    "\nTest needs to be adjusted to trigger the original bug",

test/degenerate-dash.c

@@ -77,6 +77,11 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/*
+ * XFAIL: needs path editing in PS to convert degenerate
+ * end-caps into the shapes as expected by cairo (Or maybe PS is the correct
+ * behaviour?)
+ */
 CAIRO_TEST (degenerate_dash,
 	    "Tests the behaviour of dashed segments that end on a off-on transition",
 	    "dash, degenerate", /* keywords */

test/degenerate-path.c

@@ -108,6 +108,10 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/*
+ * XFAIL: undefined behaviour in PS, needs path editing to convert degenerate
+ * segments into circles/rectangles as expected by cairo
+ */
 CAIRO_TEST (degenerate_path,
 	    "Tests the behaviour of degenerate paths with different cap types",
 	    "degenerate", /* keywords */

test/device-offset-scale.c

@@ -65,6 +65,10 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/*
+ * XFAIL: complication of pre-multiplying device_offset into the pattern_matrix
+ * and then requiring further manipulation for SVG
+ */
 CAIRO_TEST (device_offset_scale,
 	    "Test that the device-offset transform is transformed by the ctm.",
 	    "device-offset", /* keywords */

test/in-fill-empty-trapezoid.c

@@ -96,6 +96,11 @@ preamble (cairo_test_context_t *ctx)
     return ret;
 }
 
+/*
+ * XFAIL: The cairo_in_fill () function can sometimes produce false positives
+ * when the tessellator produces empty trapezoids and the query point lands
+ * exactly on a trapezoid edge.
+ */
 CAIRO_TEST (in_fill_empty_trapezoid,
 	    "Test that the tessellator isn't producing obviously empty trapezoids",
 	    "in, trap", /* keywords */

test/long-lines.c

@@ -74,6 +74,7 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/* XFAIL: range overflow of fixed-point */
 CAIRO_TEST (long_lines,
 	    "Test long lines"
 	    "\nLong lines are not drawn due to the limitations of the internal 16.16 fixed-point coordinates",

test/scale-offset-image.c

@@ -133,6 +133,7 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/* XFAIL: loss of precision converting a cairo matrix to */
 CAIRO_TEST (scale_offset_image,
 	    "Tests drawing surfaces under various scales and transforms",
 	    "surface, scale-offset", /* keywords */

test/self-copy-overlap.c

@@ -40,6 +40,11 @@ draw (cairo_t *cr, int width, int height)
     return CAIRO_TEST_SUCCESS;
 }
 
+/*
+ * XFAIL: vector surfaces take snapshot of patterns in contrast to the raster
+ * backends which don't. One solution would be to clone overlapping areas of
+ * dst/source, so patterns were effectively snapshotted across all backends.
+ */
 CAIRO_TEST (self_copy_overlap,
 	    "Tests painting to itself using itself as the source"
 	    "\nBackends treat this case inconsistently---vector backends are creating snapshots.",