System Replacement For isTest Apex Method

Sometimes we have to write code that executes differently if the Apex is being tested. For a great example, check out Scott Hemmeter's blog post on testing webservice callouts at http://sfdc.arrowpointe.com/2009/05/01/testing-http-callouts/.

Scott's example works well, and he uses a Boolean isApexTest, running certain code if this is true or false. I used to do something similar.

The disadvantage is that one has to declare one more variable, assign a new value to it from the test code (or call a special method from the test code which, in my opinion, negatively impacts code readability), and (if you put your test code in a separate class) declare it as public. My Java professor would not like this, as he preferred to declare all variables private unless absolutely necessary. Sure, I could make a private Boolean and a getter, but now we're splitting hairs.

Salesforce has come to the rescue, though, with a test.isRunningTest() method. Basically, you can use this interchangeably with your isApexTest variable.

Here's a snippet of code (from Scott's blog post) with the old and new methods:

public static boolean isApexTest = false;
public String main(){
    // Build the http request
    // Invoke web service call
    String result = '';
    if (!isApexTest){
        // Make a real callout since we are not running a test
    } else {
        // A test is running
        result = FakeXMLReturnToSimulateResponse;
    }
    return result;
}

And now with the new method:

public String main(){
    // Build the http request
    // Invoke web service call
    String result = '';
    if (!Test.isRunningTest()){
        // Make a real callout since we are not running a test
    } else {
        // A test is running
        result = FakeXMLReturnToSimulateResponse;
    }
    return result;
}

Some among you may want to switch the two so that we don't put a negative method response in the if evaluator, and that's okay too.