From 6e0201ecabc65544039790248f2eff3145088022 Mon Sep 17 00:00:00 2001
From: Brandon Rhodes <brandon@rhodesmill.org>
Date: Fri, 24 Jul 2020 04:35:13 -0400
Subject: [PATCH] For #411, get all tests running under 32-bit Linux

---
 skyfield/tests/fixes.py             |  3 +++
 skyfield/tests/test_planetarylib.py | 16 +++++++++++++---
 skyfield/tests/test_positions.py    |  5 +++--
 3 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/skyfield/tests/fixes.py b/skyfield/tests/fixes.py
index ff6306e..e61e287 100644
--- a/skyfield/tests/fixes.py
+++ b/skyfield/tests/fixes.py
@@ -1,10 +1,13 @@
 """Helpers for making Skyfield tests stable."""
 
 import datetime as dt
+import sys
+
 from skyfield import earthlib
 import skyfield.api
 import skyfield.timelib
 
+IS_32_BIT = (sys.maxsize == 0x7fffffff)
 _real_datetime_class = dt.datetime
 
 class datetime(dt.datetime):
diff --git a/skyfield/tests/test_planetarylib.py b/skyfield/tests/test_planetarylib.py
index 83877bd..5a5e429 100644
--- a/skyfield/tests/test_planetarylib.py
+++ b/skyfield/tests/test_planetarylib.py
@@ -2,6 +2,7 @@ import numpy as np
 from skyfield.api import PlanetaryConstants, T0, load
 from skyfield.constants import AU_KM, AU_M
 from skyfield.positionlib import ICRF
+from .fixes import IS_32_BIT
 
 def test_frame_rotation_matrices():
     # To produce the following matrices:
@@ -47,7 +48,10 @@ def test_frame_rotation_matrices():
 
     R2, Rv = frame.rotation_and_rate_at(ts.tdb_jd(tdb))
     assert (R == R2).all()
-    assert (Rv == desired_rate).all()  # Boom.
+    if IS_32_BIT:
+        assert abs(Rv - desired_rate).max() < 3e-26
+    else:
+        assert (Rv == desired_rate).all()  # Boom.
 
     # Second, a moment when the angle W is more than 2500 radians.
 
@@ -93,11 +97,17 @@ def test_frame_rotation_matrices():
     frame = pc.build_frame_named('MOON_ME_DE421')
     R = frame.rotation_at(ts.tdb_jd(tdb))
     delta = abs(R - desired_rotation)
-    assert (R == desired_rotation).all()
+    if IS_32_BIT:
+        assert abs(R - desired_rotation).max() < 2e-16
+    else:
+        assert (R == desired_rotation).all()
 
     R2, Rv = frame.rotation_and_rate_at(ts.tdb_jd(tdb))
     assert (R == R2).all()
-    assert (Rv == desired_rate).all()
+    if IS_32_BIT:
+        assert abs(Rv - desired_rate).max() < 2e-23
+    else:
+        assert (Rv == desired_rate).all()
 
 def test_rotating_vector_into_frame():
     et_seconds = 259056665.1855896
diff --git a/skyfield/tests/test_positions.py b/skyfield/tests/test_positions.py
index c96ff99..2bc797f 100644
--- a/skyfield/tests/test_positions.py
+++ b/skyfield/tests/test_positions.py
@@ -5,7 +5,7 @@ from skyfield.earthlib import earth_rotation_angle
 from skyfield.functions import length_of, mxv, rot_z
 from skyfield.positionlib import ICRF, ITRF_to_GCRS2, _GIGAPARSEC_AU
 from skyfield.starlib import Star
-from .fixes import low_precision_ERA
+from .fixes import IS_32_BIT, low_precision_ERA
 
 def test_subtraction():
     p0 = ICRF((10,20,30), (40,50,60))
@@ -126,7 +126,8 @@ def test_velocity_in_ITRF_to_GCRS2():
     relative_error = (length_of(actual_motion - predicted_motion)
                       / length_of(actual_motion))
 
-    assert relative_error < 2e-12
+    acceptable_error = 4e-12 if IS_32_BIT else 2e-12
+    assert relative_error < acceptable_error
 
 # Test that the CIRS coordinate of the TIO is consistent with the Earth Rotation Angle
 # This is mostly an internal consistency check