Testing package proposed for Phobos

[Walter Bright via Digitalmars-d]

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?