Unit tests for new PRNG feature.

test/test-random.js

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+/*
+ * Series of unit tests to test randomness of output.
+ */
+module.exports = {
+  setUp: function(callback) {
+    this.generator = require('./../lib/generator');
+    this.random = Math.random;
+    callback();
+  },
+
+  /*
+   * Test that using Math.random() gives us unique output.
+   */
+  testForUniqueOutput: function(test) {
+    test.notDeepEqual(generateWords(null), generateWords(null));
+    test.done();
+  },
+
+  /*
+   * Test that we can use a custom pseduo random number generator
+   * and still have unique output.
+   */
+  testForUniqueOutputWithCustomGenerator: function(test) {
+    var alea = new (require('alea'));
+
+    test.notDeepEqual(generateWords(alea), generateWords(alea));
+    test.done();
+  },
+
+  /*
+   * Test that we can create reproducible pseudo random output by
+   * seeding a custom PNRG.
+   */
+  testForReproducibleOutputWithCustomGenerator: function(test) {
+    var alea1 = new (require('alea'))('seed');
+    var alea2 = new (require('alea'))('seed');
+
+    test.deepEqual(generateWords(alea1), generateWords(alea2));
+    test.done();
+  },
+
+  /*
+   * Test that we can create pseudo random output by using unique
+   * seeds for a custom PNRG.
+   */
+  testForUniqueOutputWithCustomGeneratorWithUniqueSeeds: function(test) {
+    var alea1 = new (require('alea'))('seed');
+    var alea2 = new (require('alea'))('different-seed');
+
+    test.notDeepEqual(generateWords(alea1), generateWords(alea2));
+    test.done();
+  }
+};
+
+/*
+ * Helpers
+ */
+function generateWords(random) {
+  var generator = require('./../lib/generator');
+  var words = [];
+
+  for (var i = 0; i < 100; i++) {
+    words.push(generator({
+      count: 1,
+      units: 'words',
+      random: random
+    }));
+  }
+
+  return words.join(', ');
+}