How to ignore a test based on another test in NUnit

nunitunit testing

I'm writing some NUnit tests for database operations. Obviously, if Add() fails, then Get() will fail as well. However, it looks deceiving when both Add() and Get() fail because it looks like there's two problems instead of just one.

Is there a way to specify an 'order' for tests to run in, in that if the first test fails, the following tests are ignored?

In the same line, is there a way to order the unit test classes themselves? For example, I would like to run my tests for basic database operations first before the tests for round-tripping data from the UI.

Note: This is a little different than having tests depend on each other, it's more like ensuring that something works first before running a bunch of tests. It's a waste of time to, for example, run a bunch of database operations if you can't get a connection to the database in the first place.

Edit: It seems that some people are missing the point. I'm not doing this:

[Test]
public void AddTest()
{
    db.Add(someData);
}

[Test]
public void GetTest()
{
    db.Get(someData);
    Assert.That(data was retrieved successfully);
}

Rather, I'm doing this:

[Test]
public void AddTest()
{
    db.Add(someData);
}

[Test]
public void GetTest()
{
    // need some way here to ensure that db.Add() can actually be performed successfully
    db.Add(someData);
    db.Get(somedata);
    Assert.That(data was retrieved successfully);
}

In other words, I want to ensure that the data can be added in the first place before I can test whether it can be retrieved. People are assuming I'm using data from the first test to pass the second test when this is not the case. I'm trying to ensure that one operation is possible before attempting another that depends on it.

As I said already, you need to ensure you can get a connection to the database before running database operations. Or that you can open a file before performing file operations. Or connect to a server before testing API calls. Or…you get the point.

Best Answer

NUnit supports an "Assume.That" syntax for validating setup.This is documented as part of the Theory (thanks clairestreb). In the NUnit.Framework namespace is a class Assume. To quote the documentation:

/// Provides static methods to express the assumptions
/// that must be met for a test to give a meaningful
/// result. If an assumption is not met, the test
/// should produce an inconclusive result.

So in context:

public void TestGet() {
    MyList sut = new MyList()
    Object expecting = new Object();
    sut.Put(expecting);
    Assume.That(sut.size(), Is(1));
    Assert.That(sut.Get(), Is(expecting));
}
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