How can i force Nhibernate transaction to fail? - nhibernate

Question

How can i force Nhibernate transaction to fail(from the calling code) so i can make sure that the failing behavior is working properly?
I can't modify the source code i just need to make it fail!
example :
public void DoSomething(/*Some parameters*/){
using (var tx = _session.BeginTransaction())
{
try
{
//Do something
tx.Commit();
}
catch (Exception)
{
if (tx != null) tx.Rollback();
throw;
}
} }

Answer 1

Throw an exception.

Answer 2

Throw an exception:
using(var sess = sf.OpenSession())
using(var tx = sess.BeginTransaction())
throw new Exception();
Close the connection:
using(var sess = sf.OpenSession())
using(var tx = sess.BeginTransaction())
sess.Connection.Close();
Rollback the transaction:
using(var sess = sf.OpenSession())
using(var tx = sess.BeginTransaction())
tx.Rollback();

Answer 3

If you have to have the exception occur within the tx.Commit(), then maybe insert/update a record with invalid data (e.g. a string that's too long for the db column).

Answer 4

One idea would be while you're debugging stop at the line immediately before the query execution will be begin and turn off the database then let the code run. However I assume there is a better and more programmatic way to test this.

Answer 5

Set some global variable (I know people had global variables but this is a good use) that the transaction internal code reads and if it sees the variable set throw an exception.

Answer 6

You can write a unit test to verify the expected behaviour of your code.

Answer 7

One way to do it is:
[Test]
public void VerifyExceptionIsThrown()
{
Assert.Throws<NHibernate.HibernateException>(
() =>
{
using (var tx = _session.BeginTransaction())
{
_session.Update(new Entity());
tx.Commit();
}
});
}
An attempt to update a transient entity will throw an exeption.
Alternatively if you use the NHibernateValidator you can explicitly fail a validation you have set, say you entity's Name property should no more than 10 characters long.
If you populate your entity's Name property with a string longer than 10 characters and you try to Save it, the tx.Commit() will throw you an exception.