PCK is a central component of the professional competence of (pre-service) primary teachers in the field of mathematics, and can be differentiated into different facets. In order to examine this knowledge facet in relation to other components of professional competence (e.g., emotions, beliefs, action planning, instructional quality), an economical and freely available test procedure that sufficiently fulfils common quality criteria is needed. This paper presents partly the validation of such a test. According to test standards and in order to prove whether test scores allow for conclusions on pre-service teachers' PCK, relationships to other variables were examined. The results provide validity arguments, indicating a sufficiently high reliability of the test, and support theory-conform conclusions based on the test scores.