CSC151.02 2015S, Class 11: Testing Your Procedures, Revisited ============================================================= * Continue partners! * Quiz day is food day. _Overview_ * Preliminaries. * Admin. * Upcoming Work. * Extra Credit. * Questions. * Quiz. * Lab. * Key ideas in testing. * Careful postconditions. * Exhaustive testing. * Making yourself more efficient. Preliminaries ------------- ### Admin * Mentor session Monday at 7:00 p.m. * Friday PSA. * We'll try to to keep quizzes closer to ten minutes today. * The last fifteen minutes of today's class will be debriefing. * My life is complicated next week. We have a candidate on campus on Monday and I'm coaching the middle school MATHCOUNTS team all day Tuesday. I'll be available via email, but probably not in person, for a lot of the day. (I'll be in my office Monday at 11:00 and at 3:15, but not other times.) ### Upcoming Work * [Exam 1](../assignments/exam.01.html). * Required prologue due TONIGHT. * Exam due in electronic form next Tuesday. * Exam due in printed form next Wednesday. * Required epilogue due next Wednesday night. * You may have an extra day to do the exam because of my limited availability early next week. * Lab writeup for lab 10, due Monday, Problem 9 * Reading for Monday: * [Design and Color](../readings/design-and-color-reading.html) ### Extra Credit Opportunities #### Academic * TEDx Grinnell, sometime in February. #### Miscellaneous * Read and comment on the new _Grinnell College Guide to Preventing, Reporting, and Responding to Sexual Harassment and Sexual Misconduct_ #### Peer Support (Afternoon Section) * Track and Field, Saturday at 10 a.m., the Bear Fieldhouse (800 is the best race) * Men's Basketball, Saturday at 3:00 p.m., New Darby * Swimming, Conference Championships, February 13-15, The Osgood ### Questions _I've spent twenty minutes on this problem and I'm not making any more progress. Will I get I partial credit?_ > Ask questions after ten! Ask questions after twenty! _I'm not sure if I can ask you this, but ..._ > Be sure. You can. ### Quiz * When you finish the quiz, start working on your lab. Your partner will catch up. Lab --- * We'll stop with about fifteen minutes to go so that we can debrief. * What does `test-case` do? (test-case "Description of test" statement1 statement2 ... statementn) * Evaluate each statement in turn. * If any of the statements fails (reports an error), prints the description. * If none of the statements reports an error, prints nothing Key ideas in testing -------------------- * Tests need to be broad to catch different perspectives on what a procedure is supposed to do. * Good postconditions can lead to good tests (and vice versa) * It's hard to come up with good postconditions and good tests. * It's nice to be able to look at the code to write tests, so it's even harder because we don't have access to that code. * Try to write clear tests and clear code. * If a test fails, it may be an incorrect test rather than incorrect code. * Think carefully about your tests: You should test for different things. Careful postconditions ---------------------- * (drawing-center-x result) = x * (drawing-center-y result) = y * You want the same shape that you input. If you started with a square, you want a square. If you strated with a circle, you want a circle. * You want it the same size/dimensions Exhaustive testing ------------------ * Test shifting left and right and up and down * Different shapes: circle, squares, non-square rectangles, non-circular ellipses, compound drawings * Think about edge/corner cases: 0 * Think about weird variants: Negative targets, integer/rational, exact/inexact * A good test suite is not small. Making yourself more efficient ------------------------------