public void Verb_Choose()
{
XDatabaseContext context = new XDatabaseContext();
int[] rankPattern = new int[] { 2, 3, 1 };
// Build three arrays
int distinctCount = 100;
int length = 3 * distinctCount;
int[] id = new int[length];
int[] rank = new int[length];
int[] value = new int[length];
for (int i = 0; i < length; ++i)
{
// ID is the same for three rows at a time
id[i] = i / 3;
// Rank is [2, 3, 1] repeating (so the middle is the biggest)
rank[i] = rankPattern[i % 3];
// Value is the index of the real row
value[i] = i;
}
// Build the expected results - one for each distinct ID, each with max rank and from the right row
int[] expectedIds = new int[distinctCount];
int[] expectedRanks = new int[distinctCount];
int[] expectedValues = new int[distinctCount];
for (int i = 0; i < distinctCount; ++i)
{
expectedIds[i] = i;
expectedRanks[i] = 3;
expectedValues[i] = 3 * i + 1;
}
IXTable expected = TableTestHarness.DatabaseContext.FromArrays(distinctCount)
.WithColumn("ID", expectedIds)
.WithColumn("Rank", expectedRanks)
.WithColumn("Value", expectedValues);
IXTable actual = TableTestHarness.DatabaseContext.FromArrays(length)
.WithColumn("ID", id)
.WithColumn("Rank", rank)
.WithColumn("Value", value);
// Run and compare (as integer)
TableTestHarness.AssertAreEqual(expected, actual.Query("choose Max [Rank] [ID]", context), distinctCount / 3);
// Run and compare (as String8)
TableTestHarness.AssertAreEqual(
expected.Query("select Cast([ID], String8), Cast([Rank], String8), Cast([Value], String8)", context),
actual.Query("select Cast([ID], String8), Cast([Rank], String8), Cast([Value], String8)", context).Query("choose Max [Rank] [ID]", context),
distinctCount);
}