In many high-stakes testing situations, test-takers are not allowed to draw on external writing resources while writing, a practice observed more frequently in classroom settings. This may pose problems with the representativeness of test tasks and score interpretations. This study investigates the domain definition of one particular test known as the English Placement Writing Test within an argument-based validation framework. Focusing on the domain definition inference, the following rebuttal was evaluated: Certain essential contextual factors in the academic writing domain are not modeled in the test tasks. To do so, lower- and intermediate-level ESL students (n=92) who previously took the test were surveyed and interviewed regarding their uses of computer-based and face-to-face human-assisted writing tools. Results showed that students at both levels were statistically similar in their attitudes toward and uptakes of such tools while writing. The difference in availability of external writing tools between the target and test domain may point to issues with task authenticity of the test.