oeqa/runtime/df: don't fail on long device names

When device names are long (more than 20 characters), the
df test will fail with an exception:
    self.assertTrue(int(output)>5120, msg=msg)
    ValueError: invalid literal for int() with base 10: ''
at least when busybox is in use.

The reason is that busybox breaks the line in that case:
    Filesystem           1K-blocks      Used Available Use% Mounted on
    /dev/disk/by-partuuid/8e991e5a-cebd-4f88-9494-c9db4f30cb02
                           1998672     87024   1790408   5% /
and the code tries to extract the fourth field from the
second line, which is empty of course.

df can be told not to break lines, though, using the -P
flag, which turns on the POSIX output format, and is
supported by busybox df and coreutils df:
    Filesystem           1024-blocks    Used Available Capacity Mounted on
    /dev/disk/by-partuuid/8e991e5a-cebd-4f88-9494-c9db4f30cb02   1998672     87024   1790408   5% /

(From OE-Core rev: 8c23c1476d0c64b9bc8806db03414fa914c1e658)

Signed-off-by: André Draszik <git@andred.net>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/meta/lib/oeqa/runtime/cases/df.py b/meta/lib/oeqa/runtime/cases/df.py
index d8d79f32ea..89fd0fb901 100644
--- a/meta/lib/oeqa/runtime/cases/df.py
+++ b/meta/lib/oeqa/runtime/cases/df.py
@@ -11,7 +11,7 @@ class DfTest(OERuntimeTestCase):
     @OETestDepends(['ssh.SSHTest.test_ssh'])
     @OEHasPackage(['coreutils', 'busybox'])
     def test_df(self):
-        cmd = "df / | sed -n '2p' | awk '{print $4}'"
+        cmd = "df -P / | sed -n '2p' | awk '{print $4}'"
         (status,output) = self.target.run(cmd)
         msg = 'Not enough space on image. Current size is %s' % output
         self.assertTrue(int(output)>5120, msg=msg)