Use lines from a file as SOAP request bodies

I have a file which has one chunk of XML (representing the body of a SOAP request) per line. I want to be able to have SoapUI hit an API with requests built from each line of that file. I tried doing this in my Groovy script step:

new File('test_file').eachLine {
	{line -> 
		context.setProperty("requestBody", line)
		testRunner.runTestStepByName("RequestStep")
	}
}

My TestCase has the Groovy script step followed by the RequestStep, but all I see in the console when I run the TestCase is 

• Test started at 2017-09-06 13:27:40.729
• Step 1 [Driver] OK: took 18 ms
• -> Script-result: Script16$_run_closure1_closure2@3be77f1
• TestCase finished with status [FINISHED], time taken = 74
• Step 2 [RequestStep] OK: took 56 ms

It seems that the steps are not looping properly. Is there a way to do this?