Script Extension: When does the 'extension loading into memory' event occurs?

As a test, I created a script unit for a script extension with just the following:

var mySomething;

function getMySomething() {
    return mySomething;
}

function setMySomething(value) {
    mySomething = value;
}

function Initialize() {
    mySomething = 'this is the initial value';    
}

I encapsulated this into an extension with the following Description.XML

<ScriptExtensionGroup Name="TestThis">
    <Category Name="TestThat">
        <ScriptExtension Name="TestInitialization" Author="Robert Martin" Version="1.0">
            <Script Name="testExtensionInit.sj" InitRoutine="Initialize">
                <RuntimeObject Name="TestInit">
                    <Property Name="MySomething" GetRoutine="getMySomething" SetRoutine="setMySomething">Property description</Property>
                    <Description>Runtime object description</Description>
                </RuntimeObject>
            </Script>
            <Description>Script extension description</Description>
        </ScriptExtension>
    </Category>
</ScriptExtensionGroup>

I then wrote this code:

function blah() {
    Log.Message(TestInit.MySomething);
    TestInit.MySomething = 'New Value';
    Log.Message(TestInit.MySomething);
}

The first time I run this code after starting TestComplete I get a log that looks like this:

firstLog.png

If I run it again without restarting TestComplete, I get the following:

newLog.png

So...  the Initialization is executed at loading of TestComplete. The value in the variable persists beyond the test run so long as TestComplete has not been restarted.

If you want a variable value to be initialized in a script extension at the start of a test run, I believe you'll still need to call specific code to initialize the value.