Basilisk Known Issues¶

Caution

The use of cMsgCInterfacePy is depreciated. Use messaging instead.

Version 2.1.7¶

The streaming between vizInterface and Vizard was not reliable because of a ZMQ compatibility issue between the two code bases. BSK is reverting to using ZMQ 4.3.0 for now to avoid this issue.
Building Basilisk with opNav mode was no longer working as a conan package dependency issue came up. This has been corrected in the new version by specifying xz_utils/5.4.0 in conanfile.py. Note that building with opNav now also appears to require conan==1.59.0.

Version 2.1.6¶

in Module: boreAngCalc, the variable boreVecPoint is now called boreVec_Po.

Version 2.1.5¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
Module: hingedRigidBodyStateEffector and Module: dualHingedRigidBodyStateEffector module inertial state outputs are relative to the central gravity body, not the inertial frame. This is now corrected.
Adding an instrument camera to Module: vizInterface has changed. See BSK Scripting Settings on how to use the new method addCamMsgToModule().

Version 2.1.4¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
prior version had a bug in computer the latitude in PCPF2LLA() inside geodeticConversion. This is used in the specifyLocationPCPF() method inside Module: groundLocation, and in Module: msisAtmosphere and Module: albedo.
Module: coarseSunSensor now receives in sensorList a list of CSS configuration state pointers, not a copy to the configuration structures. This allows these values to be changed on the fly from within python. However, the simulation code must ensure that the CSS configuration structures are retained in memory or a segmentation fault will ensue.
How stand alone C-wrapped message objects are created in python has moved from cMsgCInterfacePy to messaging. Old scripts still using cMsgCInterfacePy still work as a link has been created to messaging. But, the use of cMsgCInterfacePy is no depreciated and code should be updated to using messaging instead.
The use of custom message in the external modules folders is broke with the new build modification in this release. This is fixed in the latest release.

Version 2.1.3¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
Module: planetEphemeris was not computing the correct orientation, this is fixed in current release
updated examples/OpNavScenarios/BSK_OpNav.py path to the Vizard binary. If you are calling Vizard 2.1+ from the python script, the Vizard binary name changed from Basilisk Vizard` to simply ``Vizard.
using newer versions of Python, such as 3.9.13 or 3.10.5, running conanfile.py runs into errors and fails. This is now addressed in the next release. Upgrading pip to the newest version manually can resolve this issue as well.

Version 2.1.2¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
conan version 1.44 is causing build issues because the way the source and build folders are set has changed. This is fixed in current version of Basilisk.
building Basilisk from scratch with opNav turned on was failing because conan was not able to install opencv/4.1.1. In particular, the package jasper was now failing as a required argument is no longer supported. This is fixed in the current release by turning off this jasper requirement.

Version 2.1.1¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
On windows when building with opNav mode on, the gettext library was not included with the conan software unless the version is 0.21, not 0.20.1. This dependency has been upgraded. This might require deleting the .conan folder in your home directory and re-installing all dependencies.

Version 2.1.0¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
conan changed the default repos in version 1.40 onwards which broke the Basilisk installation. This is now corrected in the latest release. After pulling the latest code release, you’ll need to delete the .conan folder in your home directory to create a fresh copy. This only has to be done once.
Module: spacecraftReconfig has been changed to read in the spacecraft mass from an input message, not be set as a module variable

Version 2.0.7¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
Over the summer of 2020 the conan repo wasn’t able to install opencv anymore. The current build fixes this issue and lets Basilisk be compiled with the opNav flag again.

Version 2.0.6¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 2.0.5¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 2.0.4¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 2.0.3¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 2.0.2¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.
On Windows, using Python 3.8 or higher resulted in Basilisk paths not being recognized due to a chance with how Python resolves paths on Windows. This is fixed in the next release.

Version 2.0.1¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 2.0.0¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.10¶

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.9

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.8

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.7

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.6

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.5

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found when opNav is included. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.4

In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.3

On Windows the vizInterface and all opNav related modules is not properly linking. Thus, all associated modules, including saving to Vizard binaries, is not working in this version.
In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.2

On Linux and Windows the vizInterface and all opNav related modules is not properly linking. Thus, all associated modules, including saving to Vizard binaries, is not working in this version.
In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found. The code compiles, but auto-completion etc. doesn’t work in that module.

Version 1.8.1

When deleting .conan and doing a build with opNav set to true, the required dependencies can’t be found on the repo on the first install run. Running it again makes it work. This is fixed in the next release to run properly on the first try.
If openCV is conan installed for Release only the Xcode would give false error messages that it can’t find the library. This is now fixed in the current release.
In Xcode, when editing vizInterface.c/h files, the protobuffer library is not properly found. The code compiles, but auto-completion etc. doesn’t work in that module.
On Linux and Windows the vizInterface and all opNav related modules is not properly linking. Thus, all associated modules, including saving to Vizard binaries, is not working in this version.

Version 1.8.0

The new conan based built system might need the conan cache folder .conan to be deleted and reset. This is typically in the user’s home folder. After this you need to re-run the conan setup commands:
```
$ conan remote add conan-community https://api.bintray.com/conan/conan-community/conan
$ conan remote add bincrafters https://api.bintray.com/conan/bincrafters/public-conan
```
If running Windows the path to the Basilisk library destination folder must be set, see Setup On Windows.
On Linux and Windows the vizInterface and all opNav related modules is not properly linking. Thus, all associated modules, including saving to Vizard binaries, is not working in this version.
If running Windows, be sure to use pip install conan to get conan, and don’t download the binary installer, see Setup On Windows. The binary installer causes several issues with this new build system in that it contains its own copy of Python, and thus checking for required python packages does work.
The new build system provides many speed improvements in doing a clean or partial build, but some small changes are required to update BSK python simulation scripts to be compatible with the new build system. These changes include:
- In BSK python simulation scripts, BSK modules should be included using the indirect method. Thus:
```
from Basilisk.fswAlgorithms.cModuleTemplate import cModuleTemplate
```
  becomes:
```
from Basilisk.fswAlgorithms import cModuleTemplate
```
- The pyswice package is now imported from topLevelModule. Thus:
```
from Basilisk import pyswice
```
  becomes:
```
from Basilisk.topLevelModules import pyswice
```
- The support file pyswice_ck_utilities.py has become a regular suppoort file in src/utiliites. Thus, it is imported using:
```
import Basilisk.pyswice.pyswice_ck_utilities
```
- Similarly, pyswice_spk_utilities.py has moved to the utilities folder. To include spkRead function replace:
```
from Basilisk.pyswice.pyswice_spk_utilities import spkRead
```
  with:
```
from Basilisk.utilities.pyswice_spk_utilities import spkRead
```
- To include loadGravFromFileToList function replace:
```
from Basilisk.simulation.gravityEffector.gravCoeffOps import loadGravFromFileToList
```
  with:
```
from Basilisk.simulation.gravityEffector import loadGravFromFileToList
```
If you have written custom BSK modules outside of the BSK distribution, the swig *.i files and some code files will need to be adjusted as follows:
- To include the swig_common_model.i file, replace:
```
%include "swig_common_model.i"
```
  with:
```
%pythoncode %{
from Basilisk.simulation.swig_common_model import *
%}
```
- If Eigen variables are being swig’d, then import:
```
%include "swig_eigen.i"
```
- To swig C arrays of variables, then import:
```
%include "swig_conly_data.i"
```
- To provide support of C++ std::string types, then import:
```
%include "std_string.i"
```
- To provide support of C++ std::vector class, then import:
```
%include "std_vector.i"
```
The files in _GeneralModuleFiles folders are now built into a separate library with the parent folders name plus Lib. This means in the IDE like Xcode and Visual Studio the code in _GeneralModuleFiles is shown in a folder with this library name. Thus, for example, code in src/simulation/environment/_GeneralModuleFiles are shown in the IDE folder environmentLib within the environment parent folder. This keeps the BSK folders cleaner and with less duplicated code being displayed.
A new python package dependency is Pillow. This is needed for the test scripts for Module: camera to run.
In Xcode the build will complain that it can’t find the <Eigen/Dense> library. The code compiles ok. The work around this conan issue is to run the build twice, once for Debug and once for Release. At that point it can be run just once.

Version 1.7.5

Module: groundLocation was not converting between the planet and inertial frame correctly. This is now fixed in the later releases.

Version 1.7.4

None

Version 1.7.3

On Windows Basilisk didn’t compile due to missing math #define delaration in geodeticConversion.cpp/h. This is fixed in the latest release.

Version 1.7.2

None

Version 1.7.1

None

Version 1.7.0

None

Version 1.6.0

None

Version 1.5.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.5.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Here the reaction wheel dynamics have been modified such that the RW state output message is no longer hard-coded to rw_config_0_data, etc. Rather, now the ModelTag string is pre-pended to make this output msg name unique with. Any scripts that is logging this RW state message will have to be updated. The reason for this change is to allow multiple spacecraft to have RW devices and unique RW state messages.
There was an issue doing a clean compile using Python 2 which is addressed in the next version
test_reactionWheelStateEffector_integrated didn’t run on Python 2, this is fixed in the next version.

Version 1.4.2

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.4.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
We ran into issues compiling on Linux where libsodium and conan were not compiling properly This is fixed in the next point release.

Version 1.4.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
BSK_PRINT has been replaced within Basilisk modules using bskLogging (for C++) and _bskLog (for C).
WINDOWS ONLY: there appears to be an issue compiling vizInterface with the new bskLog method on Windows. We are working a point release that will fix this.

Version 1.3.2

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.3.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.3.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.2.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 1.2.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The magnetometer unit tests don’t pass on all platforms. This is corrected in the next release.

Version 1.1.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
the unit tests of the magnetometer module don’t pass on all operating systems as the test tolerances are too tight. This is resolved in the next release.

Version 1.0.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Swig version 4 was released over the summer. This version is not compatible with our current Basilisk software. Be sure to install swig version 3.0.12.

Version 0.9.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Swig version 4 was released over the summer. This version is not compatible with our current Basilisk software. Be sure to install swig version 3.0.12.

Version 0.8.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Swig version 4 was released over the summer. This version is not compatible with our current Basilisk software. Be sure to install swig version 3.0.12.

Version 0.8.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Swig version 4 was released over the summer. This version is not compatible with our current Basilisk software. Be sure to install swig version 3.0.12.

Version 0.7.2

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The python pandas package is now required to run BSK. The installation instructions have been updated to reflect this.
Swig version 4 was released over the summer. This version is not compatible with our current Basilisk software. Be sure to install swig version 3.0.12.

Version 0.7.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The python pandas package is now required to run BSK. The installation instructions have been updated to reflect this.

Version 0.7.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The python pandas package is now required to run BSK. The installation instructions have been updated to reflect this.

Version 0.6.2

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The enableUnityViz python function how has different inputs. Earlier python scripts must be updated. See the scenarios for examples. The arguments are now provided as optional keywords.

Version 0.6.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
This version of Basilisk no longer support the ASIO module that communicated with the Qt-based visualization as the BOOST library has been removed. This visualization has been replaced with the new Vizard visualization.
The thrMomentumDumping now reads in a 2nd required input message to determine if a new dumping sequence is requested.

Version 0.6.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 0.5.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.

Version 0.5.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
the exponentialAtmosphere module has been replaced with a module based on the new atmospheric density base class. BSK simulations that used the older module must update to use the new module. The module unit test scripts illustrate how to use this module, and the module PDF documentation discusses this as well. The dragEffector integrated test is also updated to make use of the new module
The MRP_Feedback() has the control vector domega0 removed and keeps this term now as a permanent zero vector. Any code that was setting this needs to be updated to not set this parameter anymore.

Version 0.4.1

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The numpy python package can’t be the current version 1.16.x as this causes some incompatibilities and massive amounts of depreciated warnings. These warnings are not related to BSK python code, but other support code. Thus, for now be sure to install version 1.15.14 of numpy.

Version 0.4.0

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
Version 4.x.x and higher of pytest works again with Basilisk. You are free to install the latest version of pytest.
As we are now using the conan package management system, you can’t double the the Cmake GUI application. Instead, you must either launch the Cmake GUI application from the command line, or run CMake from the command line directly. See the platform specific Basilisk installation instructions.
The numpy python package can’t be the current version 1.16.x as this causes some incompatibilities and massive amounts of depreciated warnings. These warnings are not related to BSK python code, but other support code. Thus, for now be sure to install version 1.15.14 of numpy.

Version 0.3.3

WINDOWS ONLY: Windows users cannot currently run pytest directly on Basilisk src/ directory (there will be non-resolved python path issues that will result in erroneous ImportErrors). Instead, to verify proper installation of Basilisk, windows users must enter the specific subdirectory they are attempting to test, only then to run pytest. This should result in appropriate behavior. Right now there is no known solution to this issue.
The latest version of pytest (version 3.7.1) has a conflict with the RadiationPressure module unit test. We are still investigating. In the meantime, using pytest version 3.6.1 is working correctly.