public void GetExpressionTest()
{
var value = new List <string> {
"USA", "AUS"
};
var operation = new ExpressionBuilder.Operations.In();
var param = Expression.Parameter(typeof(Person), "x");
var parent = Expression.Property(param, "Birth");
var member = Expression.Property(parent, "Country");
var constant1 = Expression.Constant(value);
var expression = (MethodCallExpression)operation.GetExpression(member, constant1, null);
//Testing the operation structure
expression.Method.Should().BeAssignableTo <MethodInfo>();
var method = expression.Method as MethodInfo;
method.Name.Should().Be("Contains");
var property = expression.Arguments.First() as MemberExpression;
property.Member.Name.Should().Be("Country");
var constant = (ConstantExpression)expression.Object;
constant.Value.Should().Be(value);
//Testing the operation execution
var lambda = Expression.Lambda <Func <Person, bool> >(expression, param);
var people = TestData.People.Where(lambda.Compile());
var solution = TestData.People.Where(x => value.Contains(x.Birth.Country));
people.Should().BeEquivalentTo(solution);
}
public void GetExpressionWithNonListConstant_Failure()
{
var value = "USA";
var operation = new ExpressionBuilder.Operations.In();
var param = Expression.Parameter(typeof(Person), "x");
var parent = Expression.Property(param, "Birth");
var member = Expression.Property(parent, "Country");
var constant1 = Expression.Constant(value);
var ex = Assert.Throws <ArgumentException>(() => operation.GetExpression(member, constant1, null));
ex.Message.Should().Be("The 'In' operation only supports lists as parameters.");
}
public void ShouldDealNicelyWithListOfNullables()
{
var value = new List <long?> {
123, null
};
var operation = new ExpressionBuilder.Operations.In();
var param = Expression.Parameter(typeof(Person), "x");
var member = Expression.Property(param, "EmployeeReferenceNumber");
var constant1 = Expression.Constant(value);
var expression = (MethodCallExpression)operation.GetExpression(member, constant1, null);
var lambda = Expression.Lambda <Func <Person, bool> >(expression, param);
var people = TestData.People.Where(lambda.Compile());
var solution = TestData.People.Where(x => value.Contains(x.EmployeeReferenceNumber));
people.Should().BeEquivalentTo(solution);
}
