[wasm] `System.Numerics.Tests.cast_toTest.RunDoubleExplicitCastToBigIntegerTests` fails with randomized test order

[radical]

Found on #65628 which runs tests in a random order.

Random test failure with v8/linux, but seems to be reliably reproducible with XUNIT_RANDOM_ORDER_SEED=1883302047:

[03:29:54] info: Starting:    System.Runtime.Numerics.Tests.dll
[03:29:58] fail: [FAIL] System.Numerics.Tests.cast_toTest.RunDoubleExplicitCastToBigIntegerTests
[03:29:58] info: Assert.Equal() Failure
[03:29:58] info:           ↓ (pos 0)
[03:29:58] info: Expected: -0
[03:29:58] info: Actual:   0
[03:29:58] info:           ↑ (pos 0)
[03:29:58] info:    at System.Numerics.Tests.cast_toTest.VerifyDoubleExplicitCastToBigInteger(Double value)
[03:29:58] info:    at System.Numerics.Tests.cast_toTest.RunDoubleExplicitCastToBigIntegerTests()
[03:29:58] info:    at System.Reflection.RuntimeMethodInfo.InvokeWorker(Object obj, BindingFlags invokeAttr, Span`1 parameters)

To test it with that PR, make sure to <XUnitUseRandomizedTestOrderer>false</XUnitUseRandomizedTestOrderer> from the csproj.

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Issue Details

---

Found on #65628 which runs tests in a random order.

Random test failure with v8/linux, but seems to be reliably reproducible with XUNIT_RANDOM_ORDER_SEED=1883302047:

[03:29:54] info: Starting:    System.Runtime.Numerics.Tests.dll
[03:29:58] fail: [FAIL] System.Numerics.Tests.cast_toTest.RunDoubleExplicitCastToBigIntegerTests
[03:29:58] info: Assert.Equal() Failure
[03:29:58] info:           ↓ (pos 0)
[03:29:58] info: Expected: -0
[03:29:58] info: Actual:   0
[03:29:58] info:           ↑ (pos 0)
[03:29:58] info:    at System.Numerics.Tests.cast_toTest.VerifyDoubleExplicitCastToBigInteger(Double value)
[03:29:58] info:    at System.Numerics.Tests.cast_toTest.RunDoubleExplicitCastToBigIntegerTests()
[03:29:58] info:    at System.Reflection.RuntimeMethodInfo.InvokeWorker(Object obj, BindingFlags invokeAttr, Span`1 parameters)

To test it with that PR, make sure to <XUnitUseRandomizedTestOrderer>false</XUnitUseRandomizedTestOrderer> from the csproj.

Author:	radical
Assignees:	-
Labels:	arch-wasm
Milestone:	-

[vargaz]

This is still reproducible.

[vargaz]

This seems to be a problem with the test itself. It uses randomized values, which could lead to random failures.
In this case, this code:
https://github.com/dotnet/runtime/blob/main/src/libraries/System.Runtime.Numerics/tests/BigInteger/cast_to.cs#L663
is called with a value like -0.1, and it basically does:

        double value = -0.1;
        Console.WriteLine (Math.Ceiling (value).ToString () == ((BigInteger)value).ToString ());

which fails because Math.Ceiling ().ToString () returns "-0".