Spock Mock not working for unit test - groovy

Question

I am getting weird results from a Spock unit test that I thought was being caused by a misuse of Groovy's TupleConstructor annotation. However, thanks to the help of another user, I see it is a problem with the way Spock is creating mocks. Although I have fixed the issue by replacing the injected mocks with real instances, I need to in fact get mocks working here.
My main classes:
#Canonical
#TupleConstructor(callSuper = true)
abstract class Vehicle {
Long id
}
#Canonical
#TupleConstructor(callSuper = true, includeSuperProperties = true)
abstract class Foobaz extends Vehicle {
String name
String label
String description
}
#Canonical
#TupleConstructor(callSuper = true, includeSuperProperties = true)
class Fizz extends Foobaz {
// This is an empty class that creates a meaningful name over the
// abstract Foobaz parent class. This may seem like bad design in
// this analogy, but I assure you it makes sense (from a Domain-Driven
// Design perspective) in my actual application.
}
#Canonical
#TupleConstructor(callSuper = true, includeSuperProperties = true)
class Car extends Vehicle {
Fizz fizz1
Fizz fizz2
#Override
String toString() {
"${fizz1.name} - ${fizz2.name}"
}
}
My Spock test:
class CarSpec extends Specification {
def "toString() generates a correct string"() {
given: "a Car with some mocked dependencies"
String f1 = 'fizzy'
String f2 = 'buzzy'
Fizz fizz1 = Mock(Fizz)
Fizz fizz2 = Mock(Fizz)
fizz1.name >> f1
fizz2.name >> f2
Car car = new Car(1L, fizz1, fizz2)
when: "we call toString()"
String str = car.toString()
then: "we get a correctly formatted string"
"${f1} - ${f2}" == str
}
}
But when I run this I get the following failure/error:
Condition not satisfied:
"${f1} - ${f2}" == str
| | | |
fizzy buzzy | null - null
false
<omitting details here for brevity>
Expected :null - null
Actual :fizzy - buzzy
Any ideas where I'm going awry?

Answer 1

If you change your specification to this:
class CarSpec extends Specification {
def "toString() generates a correct string"() {
given: "a Car with some mocked dependencies"
String f1 = 'fizzy'
String f2 = 'buzzy'
Fizz fizz1 = Mock()
Fizz fizz2 = Mock()
Car car = new Car(1L, fizz1, fizz2)
when: "we call toString()"
String str = car.toString()
then: "we get a correctly formatted string + getProperty('name') is called once on each Mock"
"$f1 - $f2" == str
1 * fizz1.getProperty('name') >> f1
1 * fizz2.getProperty('name') >> f2
}
}
So you define the interactions in the then block, then it should all work fine...

Answer 2

From our discussion on a different one of #smeeb's questions, I looked into this a bit more since I was very confused why this wasn't working.
I created my own test.
class SomeTest extends Specification {
static class Driver {
String getName(Superclass superclass) {
return superclass.name
}
}
static abstract class Superclass {
String name
}
static class Subclass extends Superclass {
}
def 'test'() {
given:
def driver = new Driver()
def subclass = Mock(Subclass)
subclass.name >> 'test'
expect:
driver.getName(subclass) == 'test'
}
}
It failed with the same problem that #smeeb saw.
driver.getName(subclass) == 'test'
| | | |
| null | false
| Mock for type 'Subclass' named 'subclass'
I tried changing a few different things and found that when I either removed the abstract modifier from Superclass or changed the return superclass.name to return superclass.getName() the test began working.
It seems there is a weird interaction on the Groovy-level between getting inherited public fields from an abstract superclass using the auto-generated accessors.
So, in your case either remove abstract modifier from FooBaz, or change your code to:
#Override
String toString() {
"${fizz1.getName()} - ${fizz2.getName()}"
}