             .to.equal(mock.subject_detail.treatments[0].begin_date)
           # There should be sessions.
           expect(subject.sessions, "Subject is missing sessions").to.exist
-          expect(subject.sessions.length).to.equal(1)
-          expect(subject.isMultiSession).to.be.false
+          expect(subject.sessions.length, "Subject sessions length is incorrect")
+            .to.equal(1)
+          expect(subject.isMultiSession, "Subject multi-session flag is incorrect")
+            .to.be.false
           sess = subject.sessions[0]
           # There should be a parent subject.
           expect(sess.subject, "Session is missing a subject").to.exist

            end_date: moment('July 16, 2013').valueOf()
          ]
        session_detail:
          scan:
            name: 'scan'
            intensity:

          number: 1
          detail: 'a'
        subject_detail:
          _id: 'a'
          birth_date: moment([1961, 6, 7]).valueOf()
          sessions: [
            number: 1
            acquisition_date: moment('July 1, 2013').valueOf()
            detail: 'b'
            modeling: [
              name: 'pk_aUjr'
              image_container_name: 'reg_8L3W'
              fxlKTrans: 2.3
              fxrKTrans: 2.5
            ]
          ]
          encounters: [
