[FIXED] How can I mock a method an external script uses?

Issue

This is specific to Jenkins but hoping there is a generic groovy feature that can help me here.

I have a groovy script (myCustomStep.grooy) I want to unit test. It MUST be written like it is below (it cannot be a class). It will include methods that are available during Jenkins run time but not locally and I want to mock them out.

Here is one of these scripts and a corresponding test. How do I mock out echo without modifying myCustomStep.groovy?

# vars/myCustomStep.grooy
def call(Map config) {
  def paramOne = config.paramOne
  echo paramOne
}
 
class MyCustomStepTest {
  // I tried to define it here but I get "No signature of method: myCustomStep.echo()"
  def echo(message) {
    println "$message"
  }

  @Test
  public void "sdfsdfsdf"() throws Exception {
    def aaa = new GroovyShell().parse( new File( 'vars/myCustomStep.groovy' ) )
    aaa deployment: "sdlfsdfdsf"
  }
}

I can't have myCustomStep.grooy accept echo as an argument. Is there a way to monkey patch echo into the myCustomStep namespace?

EDIT: I found a simple solution but now I want to know how I can attach methods to myCustomStep for all tests instead of having to redefine for every test. I tried to do this in a @Before method (using junit) but the myCustomStep obj wasn't available to the tests.

class MyCustomStepTest {
    def myCustomStep = new GroovyShell().parse( new File( 'vars/myCustomStep.groovy' ) )

  @Test
  public void "sdfsdfsdf"() throws Exception {
    // how can I attach this once for use by all my tests?
    myCustomStep.echo = { String message -> println "$message" }
    myCustomStep deployment: "sdlfsdfdsf"
  }
}

EDIT: I was just confused about where to instantiate the object. Looks like I just need to create the object outside of the @before method and then update it inside of it.

  @Before
  public void setUp() throws Exception {
    myCustomStep.echo = { String message -> println "$message" }
  }

  def myCustomStep = new GroovyShell().parse( new File( 'vars/myCustomStep.groovy' ) )

Solution

You could put echo in the binding using something like this:

    Binding b = new Binding()
    b.echo = { println "Hello There" }
    def shell = new GroovyShell(b)
    def aaa = shell.parse( new File( 'ars/myCustomStep.groovy' ) )
    aaa deployment: "sdlfsdfdsf"

Answered By - Jeff Scott Brown