assert == on two floating numbers? Really?

[mcepl]

mypy/mypyc/test-data/run-math.test

Line 24 in fe7007f

assert repr(actual) == repr(expected), (

No wonder this immediately fails on i586 while packaging for openSUSE. Add a churn around integer math with CVE-2020-10735 and it is no wonder it doesn’t equal at all. Well, as if those things were needed over the general Programming 101 rule “Don’t use equal for floating point numbers!”.

[ 2168s] _________________________________ testMathOps __________________________________
[ 2168s] [gw0] linux -- Python 3.9.16 /usr/bin/python3.9
[ 2168s] data: /home/abuild/rpmbuild/BUILD/mypy-1.3.0/mypyc/test-data/run-math.test:3:
[ 2168s] Failed: Invalid output (/home/abuild/rpmbuild/BUILD/mypy-1.3.0/mypyc/test-data/run-math.test, line 3)
[ 2168s] ----------------------------- Captured stdout call -----------------------------
[ 2168s] 
[ 2168s] *** Exit status: 1
[ 2168s] ----------------------------- Captured stderr call -----------------------------
[ 2168s] Expected:
[ 2168s] Actual:
[ 2168s]   Traceback (most recent call last):            (diff)
[ 2168s]     File "driver.py", line 43, in <module>      (diff)
[ 2168s]       raise failures[-1][1]                     (diff)
[ 2168s]     File "driver.py", line 19, in <module>      (diff)
[ 2168s]       test_func()                               (diff)
[ 2168s]     File "run-math.test", line 50, in test_sqrt (diff)
[ 2168s]       validate_one_arg(lambda x: math.sqrt(x), pymath.sqrt) (diff)
[ 2168s]     File "run-math.test", line 24, in validate_one_arg (diff)
[ 2168s]       assert repr(actual) == repr(expected), (  (diff)
[ 2168s]   AssertionError: actual for 1.7976931348623157e+308: 1.3407807929942597e+154, expected 1.3407807929942596e+154 (diff)
[ 2168s] 

Complete build log with all details about the packages used and reproduction.

[mcepl]

Couldn’t you at least something as silly as:

---
 mypyc/test-data/run-math.test |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

Index: mypy-1.3.0/mypyc/test-data/run-math.test
===================================================================
--- mypy-1.3.0.orig/mypyc/test-data/run-math.test
+++ mypy-1.3.0/mypyc/test-data/run-math.test
@@ -8,6 +8,8 @@ from testutil import assertRaises, float
 
 pymath: Any = math
 
+FLOAT_MIN_DIFF = 0.0001
+
 def validate_one_arg(test: Callable[[float], float], validate: Callable[[float], float]) -> None:
     """Ensure that test and validate behave the same for various float args."""
     for x in float_vals:
@@ -21,9 +23,10 @@ def validate_one_arg(test: Callable[[flo
                 assert repr(e) == repr(e2), f"actual for {x!r}: {e2!r}, expected: {e!r}"
                 continue
         actual = test(x)
-        assert repr(actual) == repr(expected), (
+        assert (abs(actual - expected) / expected) < FLOAT_MIN_DIFF, (
             f"actual for {x!r}: {actual!r}, expected {expected!r}")
 
+
 def validate_two_arg(test: Callable[[float, float], float],
                      validate: Callable[[float, float], float]) -> None:
     """Ensure that test and validate behave the same for various float args."""
@@ -43,7 +46,7 @@ def validate_two_arg(test: Callable[[flo
                 actual = test(x, y)
             except Exception as e:
                 assert False, f"no exception expected for {args}, got {e!r}"
-            assert repr(actual) == repr(expected), (
+            assert (abs(actual - expected) / expected) < FLOAT_MIN_DIFF, (
                 f"actual for {args}: {actual!r}, expected {expected!r}")
 
 def test_sqrt() -> None: