Re: Testing package proposed for Phobos

[Craig Dillabaugh via Digitalmars-d]

On Monday, 9 February 2015 at 01:41:33 UTC, Walter Bright wrote:

More and more, D code is written as a component that takes a type parameters that are ranges. Unit testing becomes inconvenient, as types must be mocked up to call them. Using an array of data often is inadequate, because the component may have specializations for an array, or specifies a range that is a subset of what an array provides.

For example, here's a test range I wrote once for a unittest:

  struct Adapter
  {
      this(ubyte[] r) { this.r = r; }
      @property bool empty() { return r.length == 0; }
      @property ubyte front() { return r[0]; }
      void popFront() { r = r[1 .. $]; }
      @property size_t length() { return r.length; }

    private:
      ubyte[] r;
  }

I propose a std.test.ranges package, which contains templates defining each of the range types (InputRange, BiDirectionalRange, etc.). Each accepts an argument which is a static array of T, and then implements exactly the range interface indicated by its name, nothing more. The range will also have asserts to guarantee they are used correctly, i.e. front() cannot be called before empty() returns false.

By default, those mock range templates will be @safe. They can be configured to be @system.

Each range type will also have a corresponding testXXXRange!R(R r) function, that tests the interface to range R to ensure that it follows the protocol indicated by its name (there was some confusion a while back about exactly what the protocol entailed, having a standard test function for it will help user defined ranges be protocol correct).

Anyone interested in taking up this flag?

Google Summer of Code project?  Are you interested in mentoring?

(Sorry, I have a bit of a one-track mind)