How to carat position in plugin tests?

I'm trying to write a test for a plugin. This is the first time I've written a plugin test. At the moment I simply have:

public class MyPluginTest extends LightCodeInsightFixtureTestCase {

    @NotNull
    @Override
    protected String getTestDataPath() {
        return "src/test/resources";
    }

    public void testAddress() {
        myFixture.configureByFile("input-code/AddressImpl.java");
        int offset = myFixture.getEditor().getCaretModel().getOffset();
    }
}

Despite the fact that I've put <carat> in the test input file, the carat offset is always 0. 
I assume I'm missing another piece of configuration?

I've confirmed that the file path is correct as I get an error if it is incorrect.
I've verified that the carat returns a non-zero offset if I use configureByTest. e.g.

myFixture.configureByText("AddressImpl.java", "some dummy java code <carat> dummy code"

Thanks for any assistance.