oeqa: add output to subprocess exceptions

Out of the box subprocess.CalledProcessError.__str__() just displays the command
and exit code, which isn't very useful for debugging.

Add a function to oeqa.utils.subprocesstweak to monkey-patch __str__() so that
it can also display the value of stdout and stderr.

Signed-off-by: Ross Burton <ross.burton@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

1 files changed, 19 insertions, 0 deletions

diff --git a/meta/lib/oeqa/utils/subprocesstweak.py b/meta/lib/oeqa/utils/subprocesstweak.py
new file mode 100644
index 0000000000..1f7d11b55c
--- /dev/null
+++ b/meta/lib/oeqa/utils/subprocesstweak.py
@@ -0,0 +1,19 @@
+import subprocess
+
+class OETestCalledProcessError(subprocess.CalledProcessError):
+    def __str__(self):
+        def strify(o):
+            if isinstance(o, bytes):
+                return o.decode("utf-8", errors="replace")
+            else:
+                return o
+
+        s = "Command '%s' returned non-zero exit status %d" % (self.cmd, self.returncode)
+        if hasattr(self, "output") and self.output:
+            s = s + "\nStandard Output: " + strify(self.output)
+        if hasattr(self, "stderr") and self.stderr:
+            s = s + "\nStandard Error: " + strify(self.stderr)
+        return s
+
+def errors_have_output():
+    subprocess.CalledProcessError = OETestCalledProcessError