Psychotherapists’ emotional responses can refect important aspects of the therapeutic process (Gabbard, 2020; Hirsch, 2021). The nature or intensity of therapists’ feelings may change when the patient is engaged in testing behaviors, which may take various forms (Gazzillo, et al., 2019). Understanding these emotional states in light of the patient’s tests can assist the therapist in working to advance the therapy. In this paper we describe how the patient’s testing activity in psychotherapy can infuence therapists’ within-session emotional experiences, and how understanding such feelings can illuminate the therapeutic process. A detailed clinical case will illustrate various kinds of patient tests and associated therapist emotional states.