Bug when executing some tests using familiar in other projects

[surli]

Executing tests outside eclipse but with familiar raise an error inside gsd synthesis :

java.lang.AssertionError: null
at gsd.synthesis.Expression.(Expression.java:29)
at gsd.synthesis.Expression.(Expression.java:25)
at fr.familiar.operations.ExpressionUtility.atMost1(ExpressionUtility.java:331)
at fr.familiar.experimental.MutexGroup.toExpression(MutexGroup.java:61)

We have the problem in two different projects, the tests are all running in an eclipse console but when launching them with IntelliJ or maven, with the same setup, we just have the given error.