This study presents the development and validation of a novel multiple-choice test designed to assess university students' conceptual understanding of electric field, force, and flux. The test of understanding of electric field, force, and flux was constructed based on the results of previous studies using a phenomenographic approach to classify common errors in these concepts. The final 10-item test, designed with targeted distractors, was administered to 116 students enrolled in an introductory electricity and magnetism course. Statistical analyses, including item difficulty and discrimination indices, confirmed the reliability and discriminatory power of the test. Students' performance revealed significant misconceptions in applying the superposition principle, Gauss's law, and electric force interactions. The results of this study provide valuable insights into students' learning challenges and offer physics educators and researchers a useful tool for assessing conceptual understanding and guiding instructional improvements.