fileoverview note on exact nature of geometry expectation tests

test/browser/tests-browserified.js

@@ -544,6 +544,17 @@ suite('Explicit Error States', function() {
 /* global suite, test */
 'use strict';
 
+/**
+ * @fileoverview The tests run by this file generally compare the triangles
+ * generated by the current version of libtess against a known-good version.
+ * Note that the comparison is currently strict deep equality, meaning that not
+ * only must the vertices be found at the exact same floating-point coordinates,
+ * but the triangle vertices must be emitted in the exact same order. This
+ * limits optimizations to transformations that change neither by design.
+ * Optimizations that do change that output must be much more carefully
+ * considered in light of the careful design around numerical precision limits.
+ */
+
 var chai = require('chai');
 var assert = chai.assert;
 

test/geometry.test.js

@@ -2,6 +2,17 @@
 /* global suite, test */
 'use strict';
 
+/**
+ * @fileoverview The tests run by this file generally compare the triangles
+ * generated by the current version of libtess against a known-good version.
+ * Note that the comparison is currently strict deep equality, meaning that not
+ * only must the vertices be found at the exact same floating-point coordinates,
+ * but the triangle vertices must be emitted in the exact same order. This
+ * limits optimizations to transformations that change neither by design.
+ * Optimizations that do change that output must be much more carefully
+ * considered in light of the careful design around numerical precision limits.
+ */
+
 var chai = require('chai');
 var assert = chai.assert;