Pose3_TEST.py fails in arm64 6.9.0~pre1

[j-rivero]

Environment

• OS Version: Ubuntu Focal, arm64
• Source or binary build? during package creation

The debbuilder job from nightly today reports:

110/138 Test #110: Pose3_TEST.py ..........................***Failed    1.29 sec
......E
======================================================================
ERROR: test_stream_out (__main__.TestPose3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/var/lib/jenkins/workspace/ign-math6-debbuilder/build/ign-math/src/python/Pose3_TEST.py", line 145, in test_stream_out
    self.assertAlmostEqual(str(p), "0.1 1.2 2.3 0 0.1 1")
  File "/usr/lib/python3.8/unittest/case.py", line 943, in assertAlmostEqual
    diff = abs(first - second)
TypeError: unsupported operand type(s) for -: 'str' and 'str'

----------------------------------------------------------------------
Ran 7 tests in 0.028s

FAILED (errors=1)

Seems to happen when "subtracting a string from another that contains numbers in both strings" which seems to me the thing what we are doing here. Why is not failing in other arches?

Description

• Expected behavior: test to pass
• Actual behavior: fails making the packaging job to fail

[scpeters]

I think the problem is that assertAlmostEqual is meant for numeric types, not string types. The method starts by comparing with == and returning quickly if they match exactly, which I believe is why it works in most cases:

https://github.com/python/cpython/blob/v3.8.12/Lib/unittest/case.py#L923-L939

my guess is that the pose strings don't match exactly on arm64, which is causing assertAlmostEqual to fail drastically

[scpeters]

I've opened #255 to use assertEqual instead of assertAlmostEqual, which should improve the error message, but I still expect the test to fail.

[scpeters]

trying an arm64 build of 6.9.1~pre1:

• https://build.osrfoundation.org/job/ign-math6-debbuilder/1112/

[scpeters]

the test failure is more clear now:

110/138 Test #110: Pose3_TEST.py ..........................***Failed    0.10 sec
......F
======================================================================
FAIL: test_stream_out (__main__.TestPose3)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/jenkins/workspace/ign-math6-debbuilder/build/ignition-math-6.9.1~pre1/src/python/Pose3_TEST.py", line 145, in test_stream_out
    self.assertEqual(str(p), "0.1 1.2 2.3 0 0.1 1")
AssertionError: '0.1 1.2 2.3 -0 0.1 1' != '0.1 1.2 2.3 0 0.1 1'
- 0.1 1.2 2.3 -0 0.1 1
?             -
+ 0.1 1.2 2.3 0 0.1 1


----------------------------------------------------------------------
Ran 7 tests in 0.001s

FAILED (failures=1)

[scpeters]

potential fix in #257