Rename the external/builder/test*.js files to make it more obvious what they test

Currently you have to open the files to be certain which tests each one will run, which we can avoid by appending the directory names to the file names of the tests themselves.

external/builder/test-fixtures.js

@@ -0,0 +1,49 @@
+'use strict';
+
+require('shelljs/make');
+
+var builder = require('./builder');
+var fs = require('fs');
+
+var errors = 0;
+
+cd(__dirname);
+cd('fixtures');
+ls('*-expected.*').forEach(function(expectationFilename) {
+  var inFilename = expectationFilename.replace('-expected', '');
+  var expectation = cat(expectationFilename).trim()
+    .replace(/__filename/g, fs.realpathSync(inFilename));
+  var outLines = [];
+
+  var outFilename = function(line) {
+    outLines.push(line);
+  };
+  var defines = {
+    TRUE: true,
+    FALSE: false,
+  };
+  var out;
+  try {
+    builder.preprocess(inFilename, outFilename, defines);
+    out = outLines.join('\n').trim();
+  } catch (e) {
+    out = ('Error: ' + e.message).replace(/^/gm, '//');
+  }
+  if (out !== expectation) {
+    echo('Assertion failed for ' + inFilename);
+    echo('--------------------------------------------------');
+    echo('EXPECTED:');
+    echo(expectation);
+    echo('--------------------------------------------------');
+    echo('ACTUAL');
+    echo(out);
+    echo('--------------------------------------------------');
+    echo();
+  }
+});
+
+if (errors) {
+  echo('Found ' + errors + ' expectation failures.');
+} else {
+  echo('All tests completed without errors.');
+}