Computer Science competencies are becoming increasingly important in our current digitised society. To foster students in Computer Science, different countries have introduced subjects with new educational plans based on Computer Science frameworks, such as the K-12 CS Framework and the Informatics Reference Framework for Schools. Those include, in one way or another, four content areas: data and coding (including data structures and their applications), algorithms (involving variables, loops, and software projects), computers and networks (emphasizing the role of computers in a network and data transmission) and information society and data security (covering topics like asymmetric encryption and personal data protection). Various tests have been developed in the field of Computer Science Education for different age groups, primarily at university level for introductory Computer Science courses, and some for upper secondary school level and below, particularly for Computational Thinking. Given the research context, the objective of this study is to develop a set of items that measures the content knowledge in the four aforementioned areas. Specifically, the study focuses on the educational plan of the Computer Science subject called IMP, which is taught from the 8th to the 10th grade in secondary schools in Baden-Württemberg, Germany. In total, 155 items were evaluated by experts, resulting in a test consisting of 68 items. This poster abstract presents the ongoing progress of the test development.