public void SelectManyTests()
{
// Plan: make a series of lists of different lengths and transform them
// semi-randomly, but do the same transformation on a regular list. Then
// ensure that the VList came out the same as the plain List.
//
// Note: this test isn't included in FVListTests because the FVList.Smart
// methods act in "reverse order" compared to the LINQ methods Select/Where/etc.
// so the results wouldn't be the same between List<int> and FVList<int>.
int initialLength = 0, trial = -1;
string subtest = "";
int same = 0, pattern = 0;
try {
for (initialLength = 0; initialLength < 100; initialLength++)
{
trial = -1;
VList <int> vlist = VList <int> .Empty;
List <int> list = new List <int>();
for (int i = 0; i < initialLength; i++)
{
vlist.Add(i);
list.Add(i);
}
// First, ensure that if the list is not changed, the same list comes out
subtest = "unchanged";
Assert.AreEqual(vlist, vlist.SmartSelect(i => i));
Assert.IsTrue(vlist == vlist.SmartSelect(i => i));
Assert.AreEqual(vlist, vlist.SmartWhere(i => true));
Assert.IsTrue(vlist == vlist.SmartWhere(i => true));
Assert.AreEqual(vlist, vlist.SmartSelectMany(i => new[] { i }));
Assert.IsTrue(vlist == vlist.SmartSelectMany(i => new[] { i }));
for (trial = 0; trial < (initialLength.IsInRange(1, 10) ? 4 : 1); trial++)
{
// Number of items to keep the same at the beginning of the transform
same = initialLength == 0 ? 0 : _r.Next(8) % initialLength;
pattern = _r.Next();
int index = 0;
Func <int, int> select = n => ++ index <= same ? n : n + 1000;
Func <int, bool> where = n => ++ index <= same * 2 || ((pattern >> (index & 31)) & 1) == 0;
Func <int, IList <int> > selectMany = n =>
{
var @out = new List <int>();
if (index < same)
{
@out.Add(n);
}
else
{
for (int i = 0; i < ((pattern >> (index & 15)) & 3); i++)
{
@out.Add(index * 1000 + i);
}
}
index++;
return(@out);
};
Func <int, IEnumerable <int> > selectManyE = n => selectMany(n);
subtest = "SmartSelect";
var expectS = list.Select(select); index = 0;
var resultS = vlist.SmartSelect(select); index = 0;
ExpectList(resultS, expectS);
subtest = "SmartWhere";
var expectW = list.Where(where); index = 0;
var resultW = vlist.SmartWhere(where); index = 0;
ExpectList(resultW, expectW);
subtest = "SmartSelectMany";
var expectM = list.SelectMany(selectManyE); index = 0;
var resultM = vlist.SmartSelectMany(selectMany); index = 0;
ExpectList(resultM, expectM);
}
}
} catch (Exception e) {
e.Data["subtest"] = subtest;
e.Data["initialLength"] = initialLength;
e.Data["trial"] = trial;
e.Data["same"] = same;
e.Data["pattern"] = pattern;
throw;
}
}
