Pact Contract: Ensure Array Contains Specific Entry

[romanmusii]

I'm trying to define a contract where the producer returns an array of objects, and one of the objects in that array must match a specific pattern.

For example, the producer response might look like this:

[
  {"code": "ALPHA", "value": 12.0},
  {"code": "CHARLIE", "value": 10.5},
  ...
  {"code": "FOX", "value": 3.5},
  ...
  {"code": "ZOMBIE", "value": 7.0}
]

I want to ensure that somewhere in the returned array, there is an object with "code": "FOX". The position of this object in the array is not fixed — it just needs to be present.

If I define the contract like this:

DslPart dslPart = PactDslJsonArray.arrayMinLike(1)
    .stringType("code", "AnyCode")
    .decimalType("value", new BigDecimal("10.00"))
    .closeObject();

Then the provider test passes regardless of what code values are returned — it doesn't guarantee that "FOX" is present.

If I define it like this:

DslPart dslPart = PactDslJsonArray.arrayMinLike(1)
    .stringMatcher("code", "FOX")
    .decimalType("value", new BigDecimal("10.00"))
    .closeObject();

Then the provider test fails unless every item in the array has "code": "FOX", which is not what I want either.

Eventually, I found that I can achieve the desired check using the following DSL:

DslPart dslPart = PactDslJsonArray.newUnorderedMinArray(1)
    .object()
    .stringMatcher("code", "FOX")
    .decimalType("value", new BigDecimal("10.00"))
    .closeObject();

This seems to work as expected on the provider side — the test passes only if at least one item matches "code": "FOX".

However, the generated contract contains this matcher metadata:

"$": {
  "combine": "AND",
  "matchers": [
    {
      "match": "ignore-order",
      "min": 1
    }
  ]
}

And this causes pact-stub-server to fail with the following error:

ERROR main pact_stub_server: - Failed to load pact file: Failed to parse Pact JSON - /app/pacts/contract-service.json
ERROR main pact_stub_server: - Failed to load pact file: Could not parse matcher JSON Object {"match": String("ignore-order"), "min": Number(1)} - /app/pacts/contract-service.json

Is there a way to define a contract that ensures the array includes at least one object matching a specific pattern (e.g., "code": "FOX"), but still keeps the contract compatible with pact-stub-server?

[rholshausen]

There is an "array contains" matcher for this use case. Look for the method arrayContaining in the DSL.