hwtest

Provides methods to delay arbitrary code ("actions") and to execute the delayed actions later in FIFO order.

When delayed code is eventually executed, its resulting value will be discarded so the delayed code should be effectful.

The point of this delay is to avoid potential initialization-order bugs inside the homework object (object hw7 extends ...) that would otherwise be very confusing for students. For example, a test might indirectly depend on a val that has not yet been initialized. Instead, the test will delayed--invisibly to the student--to be executed inside the main method, after object initialization is complete.

A Reporter (in the ScalaTest sense) that displays a . for each successful test case and a X for each failed test case. For the first few failed test cases, the complete details (including input, expected output, and actual output) are displayed instead of merely an X.

Iterator through a string representing test data, primarily used as input to Parsers.

Note that the iterator normally contains all the test data for all the tests, not just the data for a single test. This "global" Src is maintained in hwtest.hw.

The Src iterator is primarly used as input to Parsers.

Note: Although Src is conceptually an iterator implementing the standard hasNext and next() methods, it does NOT inherit from the Iterator trait.

Provides the methods the test framework needs to test functions that take and/or return data of type A.

Provides many "given" Testable instances for built-in types.

Provided types include

• Int, Long, BigInt, Double
• Boolean, Char, String
• Option, List, Array
• Set, Map (from scala.collection.immutable)
• Tuple2, ..., Tuple6

Other types can be added as needed by declaring an appropriate Testable instance.

Also provides a TestableGrid instance for an array of arrays that displays its data in a grid-like format.

Base class for a homework.

The code for a typical homework will begin

 object hw7 extends hwtest.hw("CS123"):
   ...

The hw class defines a main method that runs all the tests, so the homework code (object hw7 above) does not, and in fact cannot, define a new main because the main method is final.

The default number of failed test cases (2) for which the full details will be displayed.

Failed test cases beyond this limit will display as Xs.

The intent behind this limit is two-fold:

• Seeing full details of many failed test cases is overwhelming.
• If many failed test cases are displayed, then the user will often see the bigger failed tests instead of the smaller failed tests (assuming the test cases are arranged roughly smallest to biggest), because the smaller failed test cases may have scrolled off the screen. Yet it is usually easier to spot an error in a smaller failed test case than a bigger one.

The default length of time (500 milliseconds) an individual test case in this test is allowed to run before timing out.

The minimum permitted failure limit (1).

Attempted use of a smaller limit will display a warning message and be converted to this limit instead

The minimum permitted time limit (50 milliseconds).

Attempted use of a smaller limit will display a warning message and be converted to this limit instead.

Of course, many functions should run much faster than 50 milliseconds, but accurately measuring the time taken by a function is a hard problem, especially on the JVM. Smaller time limits would likely lead to too many false negatives.

The intent of time limits is not for trying to enforce very fast running times, but rather for keeping the total time for a set of tests manageable.