Support Student-written Executable Examples (WiP)

[rjtsai]

This feature enables students to submit their own test cases as a javadoc comment above the method signature in coding exercises. These test cases are run against a provided instructor solution and displayed in the same manner as the instructor provided tests. The hope here is to increase student comprehension of what the prompt is asking for and its expected behavior.

Changes:

• added student_test_cases and student_test_case_results table to db
• added reference_solution column to coding_prompts table
• parsing functionality to grab test cases from the current attempt to save into db
• refactored some common code to app/helpers/test_case_helper.rb
• updated haml form for displaying student test case results

Demo:

• execution of student-written tests invoked by the "check" button, alongside its standard behavior
• a new reference directory is now created in usr/attempts/{term}/{current_attempt}, containing student_test_case_res
  ults and other relevant files

TODO

• cleanup perform method in app/jobs/codeworker.rb
• additional refactoring of duplicated code to test_case_helper.rb
• when instructors are creating workouts, they should be able to select whether or not to require student-written executables, and to provide a correct solution to be tested against
• Decide whether default test cases should be executed/displayed if not all student-written cases are passing

working with @ayaankazerouni

[ayaankazerouni]

Left some initial comments.