[OE-core] [PATCH 2/2] oeqa/selftest/buildoptions: Improve ccache test failure output

[Richard Purdie]

The current failure mode doesn't show us what the logs actually looked like
and later cleans can lose them. Show the whole log in case of failure
to aid debugging intermittent problems on the autobuilder.

Signed-off-by: Richard Purdie <richard.purdie at linuxfoundation.org>
---
 meta/lib/oeqa/selftest/cases/buildoptions.py | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/meta/lib/oeqa/selftest/cases/buildoptions.py b/meta/lib/oeqa/selftest/cases/buildoptions.py
index 4ebfdb71234..9b87e7fcfcc 100644
--- a/meta/lib/oeqa/selftest/cases/buildoptions.py
+++ b/meta/lib/oeqa/selftest/cases/buildoptions.py
@@ -40,8 +40,9 @@ class ImageOptionsTests(OESelftestTestCase):
         self.add_command_to_tearDown('bitbake -c clean m4')
         bitbake("m4 -f -c compile")
         log_compile = os.path.join(get_bb_var("WORKDIR","m4"), "temp/log.do_compile")
-        res = runCmd("grep ccache %s" % log_compile, ignore_status=True)
-        self.assertEqual(0, res.status, msg="No match for ccache in m4 log.do_compile. For further details: %s" % log_compile)
+        with open(log_compile, "r") as f:
+            loglines = "".join(f.readlines())
+        self.assertIn("ccache", loglines, msg="No match for ccache in m4 log.do_compile. For further details: %s" % log_compile)
 
     @OETestID(1435)
     def test_read_only_image(self):
-- 
2.17.1