public void NullExceptionArithmetic(VarType type,
BooleanTestType testType,
string operatorToTest,
int v1,
int?v2,
int v3)
{
RunTest("!=", InferError.None);
RunTest("==", InferError.NULL_DEREFERENCE);
void RunTest(string comparisonOperator, InferError expectedError)
{
var testCode = InitVars(
state: TestClassState.Null,
firstLocalVarType: type,
secondLocalVarType: type,
firstLocalVarValue: v1.ToString(),
secondLocalVarValue: v2?.ToString()) +
GenerateSingleComparisonIfCondition(
testType,
operatorToTest,
secondOperator: comparisonOperator,
valueToBeComparedAgainst: v3.ToString()) +
DerefObject(VarName.Tc);
TestRunManager.Run(testCode, GetString(expectedError));
}
}
/// <summary>
/// Helper method for generating boolean formula test code for validating that the
/// translation of an operator is correctly understood by Infer.
/// It handles three types of formulae, where v1, v2, valueToBeComparedAgainst are
/// primitive values:
/// 1. Validate unary operator: op1 x op2 y, i.e. for operator "-", -3 == -3
/// 2. Validate binary operator: (x op1 y) op2 y, i.e. for operator "+", (3 + 5) == 8
/// 3. Validate comparison operator: x op1 y, i.e. for operator ">", 4 > 3
/// In cases (1) and (2), both op2 and valueToBeComparedAgainst should be provided.
/// </summary>
/// <param name="type">The expression type, among the three options.</param>
/// <param name="firstOperator">The string representation of the first operator.</param>
/// <param name="secondOperator">The string representation of the second operator.</param>
/// <param name="valueToBeComparedAgainst">For cases (1) and (2), this is the value
/// against which the expression is compared. For case 3, it should not be
/// provided.</param>
public static string GenerateSingleComparisonIfCondition(
BooleanTestType type,
string firstOperator,
string secondOperator = null,
string valueToBeComparedAgainst = null)
{
string booleanFormula;
switch (type)
{
case BooleanTestType.Binary:
if (secondOperator == null || valueToBeComparedAgainst == null)
{
throw new ArgumentException(
"op2 and valueToBeComparedAgainst must be provided.");
}
booleanFormula =
$@"({GetString(VarName.FirstLocal)} {firstOperator}
{GetString(VarName.SecondLocal)}) {secondOperator}
{valueToBeComparedAgainst}";
break;
case BooleanTestType.Comparison:
booleanFormula = $@"{GetString(VarName.FirstLocal)}
{firstOperator}
{GetString(VarName.SecondLocal)}";
break;
case BooleanTestType.Unary:
if (secondOperator == null || valueToBeComparedAgainst == null)
{
throw new ArgumentException(
"op2 and valueToBeComparedAgainst must be provided.");
}
booleanFormula = $@"{firstOperator} {GetString(VarName.FirstLocal)}
{secondOperator}
{valueToBeComparedAgainst}";
break;
default:
throw new NotImplementedException("Unhandled BooleanTestType");
}
return("if (" + booleanFormula + ")");
}
