Test check.gstreamer-sharp.SdpTests randomly fails

=================
Test name: check.gstreamer-sharp.SdpTests
Command: 'MONO_PATH='/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/Tests/NUnit/3.10.1/lib/net45/nunit.framework.dll/..:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/Tests:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/pango:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gio:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gdk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/ges:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/glib:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/atk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gtk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/cairo:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/sources' LD_LIBRARY_PATH='//builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-editing-services/ges:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-python/gi/overrides:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/pygobject/tests:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/pygobject/tests:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/pygobject/tests:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/pygobject/gi:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/pygobject/gi:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/Tests:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/ges:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/sources:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/sample/valtest:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gtk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gdk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/atk:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/pango:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/cairo:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/gio:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gtk-sharp/Source/glib:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-editing-services/ges:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-devtools/validate/gst/overrides:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-devtools/validate/gst/validate:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-rtsp-server/gst/rtsp-server:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/dssim:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/webrtc:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/wayland:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/sctp:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/player:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/opencv:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/mpegts:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/isoff:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/interfaces:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/insertbin:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/codecparsers:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/basecamerabinsrc:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/audio:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/adaptivedemux:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-bad/gst-libs/gst/uridownloader:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/gl:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/allocators:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/app:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/riff:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/pbutils:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/rtsp:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/sdp:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/rtp:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/audio:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/video:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/fft:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gst-plugins-base/gst-libs/gst/tag:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer/libs/gst/check:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer/libs/gst/net:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer/libs/gst/controller:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer/libs/gst/base:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer/gst:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/orc/orc-test:/builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/orc/orc:/builds/seungha.yang/gst-editing-services/gst-build/prefix/lib' /usr/bin/nunitlite-runner /builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/Tests/SdpTests.dll'
=================

NUnitLite 3.7.1 (.NET 4.5)
Copyright (C) 2017 Charlie Poole

Runtime Environment
   OS Version: Unix 4.9.0.5
  CLR Version: 4.0.30319.42000

Test Files
    /builds/seungha.yang/gst-editing-services/gst-build/build/subprojects/gstreamer-sharp/Tests/SdpTests.dll

Errors, Failures and Warnings

1) Error : GstSharp.Tests.SdpTests.TesSdpMessage
TearDown : System.NullReferenceException : Object reference not set to an instance of an object
--TearDown
  at GstSharp.Tests.TestBase.BaseTearDown () [0x00000] in <d27f093427404827a9be90e600b41ec3>:0 
  at (wrapper managed-to-native) System.Reflection.MonoMethod:InternalInvoke (System.Reflection.MonoMethod,object,object[],System.Exception&)
  at System.Reflection.MonoMethod.Invoke (System.Object obj, System.Reflection.BindingFlags invokeAttr, System.Reflection.Binder binder, System.Object[] parameters, System.Globalization.CultureInfo culture) [0x00038] in <373b6e083d6e45e498c9082a8eebd27f>:0 

Run Settings
    Number of Test Workers: 8
    Work Directory: /builds/seungha.yang/gst-editing-services/gst-build
    Internal Trace: Off

Test Run Summary
  Overall result: Failed
  Test Count: 1, Passed: 0, Failed: 1, Warnings: 0, Inconclusive: 0, Skipped: 0
    Failed Tests - Failures: 0, Errors: 1, Invalid: 0
  Start time: 2019-03-06 13:40:42Z
    End time: 2019-03-06 13:40:42Z
    Duration: 0.130 seconds

Results (nunit3) saved as /builds/seungha.yang/gst-editing-services/gst-build/TestResult.xml