Update a Map in groovy spock framework - groovy

Question

I have the below spock specification and want to update the map from data table. Can some body help achieve this
def "groovy map update"() {
setup: "step1"
Map json = [
user :[
name : 'ABC'
]]
when: "step2"
println ('Before modification:')
println (json)
then: "step3"
json.with {
//user.name = value // this one works
(field) = value // this one does not work
}
println ('After modification:')
println (json)
where:
field | value
'user.name' | 'XYZ'
}

Answer 1

The then section is intended for asserts and not for updates etc. So you have to update the map in the when section and then test the result in the then section. For example like this:
def "groovy map update"() {
setup: 'create json'
Map json = [user: [name: 'ABC']]
when: 'update it'
def target = json
for (node in path - path.last()) {
target = target[node]
}
target[path.last()] = value
then: 'check the assignment'
json.user.name == value
where:
path | value
['user', 'name'] | 'XYZ'
}
One way how to update nested Map value can be by using list of path nodes instead of field notation and then iterate over them to obtain the last Map instance and set the value there:
def target = json
for (node in path - path.last()) {
target = target[node]
}
target[path.last()] = value

Answer 2

The accepted solution is correct, I just want to show an alternative doing the same in a slightly different way, assuming you want to stick with the dotted notation for field in your where: block. I just added two more test cases in order to make sure it works as expected.
#Unroll
def "set #field to #value"() {
setup: 'create json'
Map json = [user: [name: 'ABC', address: [street: '21 Main St', zip: '12345', city: 'Hometown']]]
when: 'update it'
def subMap = json
field.split("[.]").each {
if (subMap[it] instanceof Map)
subMap = subMap[it]
else
subMap[it] = value
}
println json
then: 'check the assignment'
json.newField == value ||
json.user.name == value ||
json.user.address.zip == value
where:
field | value
'newField' | 'dummy'
'user.name' | 'XYZ'
'user.address.zip' | '98765'
}
Update: If you want to save a few lines of code you can also use a fold (or reduce or accumulate) operation via inject(..) as described here
#Unroll
def "set #field to #value"() {
setup: 'create json'
Map json = [user: [name: 'ABC', address: [street: '21 Main St', zip: '12345', city: 'Hometown']]]
when: 'update it'
field.split("[.]").inject(json) { subMap, key ->
subMap[key] instanceof Map ? subMap[key] : subMap.put(key, value)
}
println json
then: 'check the assignment'
json.newField == value ||
json.user.name == value ||
json.user.address.zip == value
where:
field | value
'newField' | 'dummy'
'user.name' | 'XYZ'
'user.address.zip' | '98765'
}
Whether you find that readable or not may depend on your familiarity with topics like functional programming in general or map/reduce in particular. The charm here in addition to brevity is that we no longer need a local variable outside of our closure but we just inject (hence the method name) the result of iteration n to iteration n+1.
BTW, as a nice side effect inject(..) as I am using it here returns the previous value of the value you set or overwrite. Just add println in front of field.split("[.]").inject(json) ... in order to see it.
Update 2: Please note that both variants only work if there is no existing field value of type Map in the target field because of the instanceof Map check heuristics in my code. I.e. these two cases would not work:
'user.address' | [street: '23 Test Blvd', zip: '33333', city: 'Somewhere']
'user.address' | '23 Test Blvd, 33333 Somewhere'
This one would work, though, because there is no preexisting value:
'user.alternativeAddress' | [street: '23 Test Blvd', zip: '33333', city: 'Somewhere']