[test] Use a different jpeg image for mime-data

Detect when we successfully encode the JPEG data from the mime-type by
using a completely image.

test/Makefile.am

@@ -694,6 +694,8 @@ REFERENCE_IMAGES = \
 	meta-surface-pattern.svg12.argb32.ref.png	\
 	meta-surface-pattern.svg12.rgb24.ref.png	\
 	mime-data.ref.png	\
+	mime-data.ps.ref.png	\
+	mime-data.pdf.ref.png	\
 	miter-precision.ref.png \
 	miter-precision.ps2.ref.png	\
 	miter-precision.ps3.ref.png	\
@@ -1002,6 +1004,7 @@ EXTRA_DIST +=		\
 make-html.pl		\
 romedalen.jpg		\
 romedalen.png		\
+scarab.jpg		\
 surface-source.c	\
 $(REFERENCE_IMAGES)
 

test/mime-data.c

@@ -35,7 +35,11 @@ read_jpg_file (const cairo_test_context_t *ctx,
 	       unsigned char **data_out,
 	       unsigned int *length_out)
 {
-    const char jpg_filename[] = "romedalen.jpg";
+    /* Deliberately use a non-matching jpeg image, so that we can identify
+     * when the JPEG representation is used in preference to the image
+     * surface.
+     */
+    const char jpg_filename[] = "scarab.jpg";
     FILE *file;
     unsigned char *buf;
     unsigned int len;