Experimental SkewBinomialHeap Tests failing

[jackfoxy]

Description

tests marked ptestPropertyWithConfig as well as most commented-out SkewBinomialHeap Tests fail

Repro steps

1. change ptestPropertyWithConfig to testPropertyWithConfig (remove "p")

2. run tests

Expected behavior

pass
See commit 2918045 for tests passing as NUnit tests before conversion to Expecto and F# was at 4.0.
Since then projects have been updated first to F#.Core 4.1 and now 4.5.
Also previous passing tests were on older version of FsCheck.

Actual behavior

System.Exception: The type System.IComparable is not handled automatically by FsCheck. Consider using another type or writing and registering a generator for it.
   at [email protected](String message)
   at [email protected](Type t)
   at FsCheck.Common.f@1[a,b](IDictionary`2 memo, FSharpFunc`2 f, a n, Unit _arg1)
   at FsCheck.Common.memoizeWith[a,b](IDictionary`2 memo, FSharpFunc`2 f, a n)
   at [email protected]_Generator()
   at FSharpx.Collections.Experimental.Tests.SkewBinomialHeapTest.emptyOnly@139-1.Invoke(Boolean _arg1)
   at [email protected](Int32 n, StdGen r0)
   at [email protected](Int32 n, StdGen r0)
   at [email protected](IEnumerable`1& next)
   at Microsoft.FSharp.Core.CompilerServices.GeneratedSequenceBase`1.MoveNextImpl()
   at [email protected](IEnumerable`1& next)
   at Microsoft.FSharp.Core.CompilerServices.GeneratedSequenceBase`1.MoveNextImpl()
   at [email protected](IEnumerable`1& next)
   at Microsoft.FSharp.Core.CompilerServices.GeneratedSequenceBase`1.MoveNextImpl()
   at Microsoft.FSharp.Collections.SeqModule.Fold[T,TState](FSharpFunc`2 folder, TState state, IEnumerable`1 source)
   at FsCheck.Runner.runner[a](Config config, a prop)
   at FsCheck.Runner.check[a](Config config, a p)
   at [email protected](FsCheckConfig config)
   at [email protected](Unit unitVar)
   at Microsoft.FSharp.Control.AsyncPrimitives.CallThenInvoke[T,TResult](AsyncActivation`1 ctxt, TResult result1, FSharpFunc`2 part2)
   at <StartupCode$FSharp-Core>[email protected](AsyncActivation`1 ctxt)
   at Microsoft.FSharp.Control.Trampoline.Execute(FSharpFunc`2 firstAction)

Known workarounds

Rewrite existing tests to not use type System.IComparable

Related information

fscheck/FsCheck#443 may resolve this issue.