Normalize files containing unit test code:

Source files are split to place all unit test code into translation
units ending in .test.cpp with no other business logic in the same file,
and in directories named "test".

A new target is added to the SConstruct, invoked by:
    scons count
This prints the total number of source code lines occupied by unit tests,
in rippled specific code and excluding library subtrees.

src/ripple/basics/tests/KeyCache.test.cpp

@@ -0,0 +1,96 @@
+//------------------------------------------------------------------------------
+/*
+    This file is part of rippled: https://github.com/ripple/rippled
+    Copyright (c) 2012, 2013 Ripple Labs Inc.
+
+    Permission to use, copy, modify, and/or distribute this software for any
+    purpose  with  or without fee is hereby granted, provided that the above
+    copyright notice and this permission notice appear in all copies.
+
+    THE  SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+    WITH  REGARD  TO  THIS  SOFTWARE  INCLUDING  ALL  IMPLIED  WARRANTIES  OF
+    MERCHANTABILITY  AND  FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+    ANY  SPECIAL ,  DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+    WHATSOEVER  RESULTING  FROM  LOSS  OF USE, DATA OR PROFITS, WHETHER IN AN
+    ACTION  OF  CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+//==============================================================================
+
+#include <ripple/basics/KeyCache.h>
+
+#include <beast/unit_test/suite.h>
+#include <beast/chrono/manual_clock.h>
+
+namespace ripple {
+
+class KeyCache_test : public beast::unit_test::suite
+{
+public:
+    void run ()
+    {
+        beast::manual_clock <std::chrono::steady_clock> clock;
+        clock.set (0);
+
+        typedef std::string Key;
+        typedef KeyCache <Key> Cache;
+
+        // Insert an item, retrieve it, and age it so it gets purged.
+        {
+            Cache c ("test", clock, 1, 2);
+
+            expect (c.size () == 0);
+            expect (c.insert ("one"));
+            expect (! c.insert ("one"));
+            expect (c.size () == 1);
+            expect (c.exists ("one"));
+            expect (c.touch_if_exists ("one"));
+            ++clock;
+            c.sweep ();
+            expect (c.size () == 1);
+            expect (c.exists ("one"));
+            ++clock;
+            c.sweep ();
+            expect (c.size () == 0);
+            expect (! c.exists ("one"));
+            expect (! c.touch_if_exists ("one"));
+        }
+
+        // Insert two items, have one expire
+        {
+            Cache c ("test", clock, 2, 2);
+
+            expect (c.insert ("one"));
+            expect (c.size  () == 1);
+            expect (c.insert ("two"));
+            expect (c.size  () == 2);
+            ++clock;
+            c.sweep ();
+            expect (c.size () == 2);
+            expect (c.touch_if_exists ("two"));
+            ++clock;
+            c.sweep ();
+            expect (c.size () == 1);
+            expect (c.exists ("two"));
+        }
+
+        // Insert three items (1 over limit), sweep
+        {
+            Cache c ("test", clock, 2, 3);
+
+            expect (c.insert ("one"));
+            ++clock;
+            expect (c.insert ("two"));
+            ++clock;
+            expect (c.insert ("three"));
+            ++clock;
+            expect (c.size () == 3);
+            c.sweep ();
+            expect (c.size () < 3);
+        }
+    }
+};
+
+BEAST_DEFINE_TESTSUITE(KeyCache,common,ripple);
+
+}