Add the eachKeyLike matcher

[luizesramos]

🗣 Context

The current Pact DLS defines the eachKeyLike Matcher with an example here

The Java implementation of the Matcher and describes eachKeyLike as:

Accepts any key, and each key is mapped to a map that must match the 
following/provided object definition Note: this needs the Java system property 
"pact.matching.wildcard" set to value "true" when the pact file is verified.

pact-js implementation of eachKeyLike matcher.

💬 Narrative

When the Producer issues a response containing a dictionary with one or more Keys
I want to be able to validate the type and format of the Values in the dictionary without knowing the Keys
So that I can add or remove values from the Producer's dictionary without the Consumer flagging a contract issue.

📝 Notes

🏗 Design

Example: this service response

{
  "abc": { "field1": "value1", "field2": 123 },
  "xyz": { "field1": "value2", "field2": 456 }
}

Could be validated with

Matcher.eachKeyLike([
  "field1":  Matcher.somethingLike("a string"),
  "field2": Matcher.somethingLike(0)
])

Note: the response validation is possible without knowing the keys "abc" and "xyz" in the service response above.

✅ Acceptance Criteria

GIVEN a dictionary populated with key-value pairs
WHEN the eachKeyLike matcher is applied on the dictionary
THEN the broker will not make assertions on the dictionary key, only on the values.

🚫 Out of Scope

Regex validation for the keys. We can create a follow-up issue for that, if the DSL requires it.

[surpher]

Matcher.EachKeyLike(_:) has been added to PactSwift on branch feature/matcher-each-key-like. This is the first MVP to support this. In the future might find some more time to allow different variations of the struct's init (eg: passing in a dictionary). For now, this should suffice.

For the following response containing "abc" and "xyz" during consumer test and where they should be considered as wildcards at provider verification time:

{
  "abc": { "field1": "value1", "field2": 123 },
  "xyz": { "field1": "value2", "field2": 456 }
}

use the EachKeyLike matcher as:

.willRespondWith(
  status: 200,
  body: [
    "abc": Matcher.EachKeyLike([ 
        "field1": Matcher.SomethingLike("value1"),
        "field2": Matcher.IntegerLike(123)
    ]),
    "xyz": Matcher.EachKeyLike([
      "field1": Matcher.SomethingLike("value2"),
      "field2": Matcher.IntegerLike(456)
    ])
  ]
)

The generated matchers will look like:

"matchingRules": {
  "body": {
    "$.*": {
      "combine": "AND",
      "matchers": [{"match": "type"}]
    },
    "$.*.field1": {
      "combine": "AND",
      "matchers": [{"match": "type"}]
    },
    "$.*.field2": {
      "combine": "AND",
      "matchers": [{"match": "integer"}]
    }
  }
},

[surpher]

Available from PactSwift v0.13.0.