One of the common situation that I come across while talking about the contract testing to my teams is - How to handle the cases where there are intermediator/pass-through services between the

real

consumer and provider for the specific data ? I will try to explain through an example, •

CartService

: is a consumer of these services -

CustomerInformationService

,

ProductCatalogService

and

PricingService

. • For the

CartService.addItemToCart()

operation, It retrieves data from

CustomerInformationService

and

ProductCatalogService

and pass it on to the

PricingService

along with its own data, the current

cart

and

itemToBeAdded

.

PriciningService

uses these combined information to apply the discounts or other free items based on the business rules. • In this case,

CartService

really does not dictate what information it is presented by the

CustomerInformationService

and

ProductCatalogService

and act as pretty much pass-through. Questions are - • How the contracts are supposed to be written by the

CartService

for the information that it depends on other services? • How the collaboration supposed to be happened ? Should

PricingService

be aware about the contract of the

CustomerInformationService

and

ProductCatalogService

? PS: this is my first message in the PACT community after 4 years. I have my own views on the above, but would like to get community views as well.

Nice to hear from you!

@Matt (pactflow.io / pact-js / pact-go) , since the since the pass-thru services usually don’t care about the data and often do not validate, the contract testing becomes challenging. One of the option is to validate generically without parsing the payload for specific validation is to have a shared registry for dynamic schemas such as product catalog items and validate the payload against them using the indirection.

Yes. We created https://pactflow.io/bi-directional-contract-testing/ in part because of this inconvenience

Yes, I am aware the bi-directional contract testing. However, I am think current support is limited to the OpenApi based validation only. What I am referring to dynamic schema for cases like product-catalog above, where different products and business rules are added dynamically without application code changes, and the services involve are implemented using abstractions(like TMF Api as open standards for telecos)

Would be more than open to the idea and seeing where it takes you!