Oops, it's more like that:

Adapt.course.set('_isAssessmentPassed', stateModel.assessmentsPass == stateModel.assessments);

and don't forget to add assessmentsPass in the return in assessments.js

return {
 isComplete: isComplete,
 isPercentageBased: assessmentsConfig._isPercentageBased,
 requireAssessmentPassed: assessmentsConfig._requireAssessmentPassed,
 isPass: isPass,
 scoreAsPercent: scoreAsPercent,
 maxScore: maxScore,
 score: score,
 assessmentsComplete: assessmentsComplete,
 assessmentsPass: assessmentsPass,
 assessments: totalAssessments
};