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public void testTypicalResults( ) {
Account accounts[] = new Account[3];
accounts[0] = new Account( );
accounts[0].principal = 35;
accounts[0].rate = (float) .04;
accounts[0].daysActive = 365;
accounts[0].accountType = Account.PREMIUM;

accounts[1] = new Account( );
accounts[1].principal = 100;
accounts[1].rate = (float) .035;
accounts[1].daysActive = 100;
accounts[1].accountType = Account.BUDGET;
accounts[2] = new Account( );
accounts[2].principal = 50;
accounts[2].rate = (float) .04;
accounts[2].daysActive = 600;
accounts[2].accountType = Account.PREMIUM_PLUS;

float result = feeCalculation.calculateFee(accounts);
assertEquals(result, (float) 0.060289, (float) 0.00001);
}

This test passes. The call to feeCalculation( ) with those three accounts returns a value of
0.060289383, which matches the value passed to assertEquals( ) within the specified toler-
ance of .000001. The assertion does not cause a failure, and the test case completes.
It’s important to test unexpected input. The programmer may not have expected
feeCalculation( ) to receive a set of accounts that contained no premium accounts. So the
second test checks for a set of non-premium accounts:

public void testNonPremiumAccounts( ) {
Account accounts[] = new Account[2];

accounts[0] = new Account( );
accounts[0].principal = 12;
accounts[0].rate = (float) .025;
accounts[0].daysActive = 100;
accounts[0].accountType = Account.BUDGET;

accounts[1] = new Account( );
accounts[1].principal = 50;
accounts[1].rate = (float) .0265;
accounts[1].daysActive = 150;
accounts[1].accountType = Account.STANDARD;

float result = feeCalculation.calculateFee(accounts);
assertEquals(result, 0, 0.0001);
}
The expected result for this test is 0, and it passes.

DESIGN AND PROGRAMMING 159