public void GetRateForDate()
{
// First test is with empty data
FMainDS.LoadAll();
FMainDS.DeleteAllRows();
FMainDS.SaveChanges();
FLedgerDS.CreateTestLedger();
// define our working date range
DateTime dtStart = new DateTime(2000, 01, 01);
DateTime dtEnd = new DateTime(2000, 12, 31);
// First test is with empty data - should return 1.0m
TFrmSetupDailyExchangeRate mainScreen = new TFrmSetupDailyExchangeRate(null);
decimal result = mainScreen.GetLastExchangeValueOfInterval(STANDARD_TEST_LEDGER_NUMBER, dtStart, dtEnd, "GBP");
Assert.AreEqual(1.0m, result, "The result should be 1.0m when the table contains no data");
// Repeat test with data but outside the date range - again should return 1.0m
FMainDS.InsertStandardModalRows();
FMainDS.SaveChanges();
mainScreen = new TFrmSetupDailyExchangeRate(null);
result = mainScreen.GetLastExchangeValueOfInterval(STANDARD_TEST_LEDGER_NUMBER, dtStart, dtEnd, "GBP");
Assert.AreEqual(1.0m, result, "The result should be 1.0m because there is no data in the date range");
// Repeat again with data inside the range
FMainDS.AddARow("GBP", STANDARD_TEST_CURRENCY, new DateTime(2000, 6, 1), 2.0m);
FMainDS.AddARow("GBP", STANDARD_TEST_CURRENCY, new DateTime(2000, 6, 10), 2.05m);
FMainDS.AddARow("GBP", STANDARD_TEST_CURRENCY, new DateTime(2000, 6, 30), 2.15m); // This is the latest
FMainDS.AddARow("GBP", STANDARD_TEST_CURRENCY, new DateTime(2000, 6, 20), 2.10m);
FMainDS.SaveChanges();
mainScreen = new TFrmSetupDailyExchangeRate(null);
result = mainScreen.GetLastExchangeValueOfInterval(STANDARD_TEST_LEDGER_NUMBER, dtStart, dtEnd, "GBP");
Assert.AreEqual(2.15m, result);
}