public void PartitionIf_WithNonEmptyEnumerableAndAnyIndex_ExpectsEnumerablesOfSameTotalLength()
 => Utilities.AssertManySequencesEqual(
     ENMRBL_NON_EMPTY.PartitionIf((index, item) => index < COUNT_ANY),
     new[] {
     ENMRBL_NON_EMPTY.Take(COUNT_ANY),
     ENMRBL_NON_EMPTY.Skip(COUNT_ANY),
 });
 public void PartitionIf_WithNonEmptyEnumerableAndAlwaysOtherPartition_ExpectsEnumerableOfEmpties()
 => Utilities.AssertManySequencesEqual(
     ENMRBL_NON_EMPTY.PartitionIf(AlwaysOtherPartition).Take(COUNT_BIG),
     Enumerable.Range(0, COUNT_BIG).Select(item => new MultiItems[0]));
 public void PartitionIf_WithNonEmptyEnumerableAndAlwaysSamePartition_ExpectsSameEnumerableAsSingleEnumerable()
 => Utilities.AssertManySequencesEqual(
     ENMRBL_NON_EMPTY.PartitionIf(AlwaysSamePartition),
     Enumerable.Repeat(ENMRBL_NON_EMPTY, 1));