[Piglit] [PATCH] framework/backends/json.py: present a nice error message if a json resluts file is corrupt

[Dylan Baker]

If a complete result is corrupt, currently an exception will be raised
and caught at the root (this will be an Exception, but a
PiglitFatalError), this will result in a bug message.

With this patch the corrupt file will be identified as well as the error
presented by the json module about the underlying file.

Signed-off-by: Dylan Baker <dylanx.c.baker at intel.com>
---
 framework/backends/json.py            |  9 ++++++++-
 framework/tests/json_backend_tests.py | 12 ++++++++++--
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/framework/backends/json.py b/framework/backends/json.py
index 9d76c49..2fe239c 100644
--- a/framework/backends/json.py
+++ b/framework/backends/json.py
@@ -212,7 +212,14 @@ def _load(results_file):
     """
     result = results.TestrunResult()
     result.results_version = 0  # This should get overwritten
-    result.__dict__.update(json.load(results_file, object_hook=piglit_decoder))
+    try:
+        result.__dict__.update(
+            json.load(results_file, object_hook=piglit_decoder))
+    except ValueError as e:
+        raise exceptions.PiglitFatalError(
+            'While loading json results file: "{}",\n'
+            'the following error occured:\n{}'.format(results_file.name,
+                                                      e.message))
 
     return result
 
diff --git a/framework/tests/json_backend_tests.py b/framework/tests/json_backend_tests.py
index e537362..889332a 100644
--- a/framework/tests/json_backend_tests.py
+++ b/framework/tests/json_backend_tests.py
@@ -18,7 +18,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
-# pylint: disable=missing-docstring
+# pylint: disable=missing-docstring,protected-access
 
 """ Tests for the backend package """
 
@@ -31,7 +31,7 @@ except ImportError:
     import json
 import nose.tools as nt
 
-from framework import results, backends
+from framework import results, backends, exceptions
 import framework.tests.utils as utils
 from .backends_tests import BACKEND_INITIAL_META
 
@@ -295,3 +295,11 @@ def test_piglit_decoder():
     test = json.loads('{"foo": {"result": "pass"}}',
                       object_hook=backends.json.piglit_decoder)
     nt.assert_is_instance(test['foo'], results.TestResult)
+
+
+ at nt.raises(exceptions.PiglitFatalError)
+def test_load_bad_json():
+    """backends.json._load: Raises fatal error if json is corrupt"""
+    with utils.tempfile('{"bad json": }') as f:
+        with open(f, 'r') as tfile:
+            backends.json._load(tfile)
-- 
2.4.0