pact-foundation/pact-jvm

Pact weird behaviour in the contract if same test is present in two class files for same consumer and provider pair.

Open

#1893 opened on Jan 12, 2026

View on GitHub
 (11 comments) (0 reactions) (0 assignees)Groovy (1,127 stars) (486 forks)batch import
buggood first issuehelp wantedtriage

Description

I was writing this scenario, where accidently I had written the a test case in two different class with same consumer and provider pair which is having Authorization header in the api request.

So when I publish the contract from one test class, contract was perfectly fine, but when I ran the second test class with exact same test case and publish the contract there was extra space coming in the authorization header.

Not sure why this happen?

Contributor guide

Tech stack
java
Domain
testingapi
Issue type
bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
3
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
half day
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
needs investigation
Prerequisites
JVMPact basics
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
30
Research direction
Investigate the contract merging logic in Pact JVM, specifically how interactions from multiple test classes with the same consumer provider pair are combined. The issue suggests that duplicate test cases cause an extra space in authorization headers. Look at the source files responsible for writing the pact file, possibly in the PactWriter or related classes. Check for any string concatenation or formatting that might introduce whitespace when interactions are appended.