First commit

node_modules/backoff/tests/exponential_backoff_strategy.js

@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2012 Mathieu Turcotte
+ * Licensed under the MIT license.
+ */
+
+var sinon = require('sinon');
+
+var ExponentialBackoffStrategy = require('../lib/strategy/exponential');
+
+exports["ExponentialBackoffStrategy"] = {
+
+    "backoff delays should follow an exponential sequence": function(test) {
+        var strategy = new ExponentialBackoffStrategy({
+            initialDelay: 10,
+            maxDelay: 1000
+        });
+
+        // Exponential sequence: x[i] = x[i-1] * 2.
+        var expectedDelays = [10, 20, 40, 80, 160, 320, 640, 1000, 1000];
+        var actualDelays = expectedDelays.map(function () {
+            return strategy.next();
+        });
+
+        test.deepEqual(expectedDelays, actualDelays,
+            'Generated delays should follow an exponential sequence.');
+        test.done();
+    },
+
+    "backoff delay factor should be configurable": function (test) {
+        var strategy = new ExponentialBackoffStrategy({
+            initialDelay: 10,
+            maxDelay: 270,
+            factor: 3
+        });
+
+        // Exponential sequence: x[i] = x[i-1] * 3.
+        var expectedDelays = [10, 30, 90, 270, 270];
+        var actualDelays = expectedDelays.map(function () {
+            return strategy.next();
+        });
+
+        test.deepEqual(expectedDelays, actualDelays,
+            'Generated delays should follow a configurable exponential sequence.');
+        test.done();
+    },
+
+    "backoff delays should restart from the initial delay after reset": function(test) {
+        var strategy = new ExponentialBackoffStrategy({
+            initialDelay: 10,
+            maxDelay: 1000
+        });
+
+        strategy.next();
+        strategy.reset();
+
+        var backoffDelay = strategy.next();
+        test.equals(backoffDelay, 10,
+            'Strategy should return the initial delay after reset.');
+        test.done();
+    }
+};