diff --git a/index.js b/index.js
index de5824a..6c7841d 100644
--- a/index.js
+++ b/index.js
@@ -177,13 +177,15 @@ class NeverRefreshPolicy {
 // Refresh if we haven't refreshed recently
 class StaleRefreshPolicy {
   constructor(duration) {
-    // TODO Validate
+    if (!duration || duration <= 0) {
+      throw new Error('Invalid duration');
+    }
     this.duration = duration;
   }
 
   shouldRefresh() {
-    if (!this.lastRefresh || moment.now() > this.lastRefresh.add(this.duration)) {
-      this.lastRefresh = moment.now();
+    if (!this.lastRefresh || moment() > this.lastRefresh.add(this.duration, 'ms')) {
+      this.lastRefresh = moment();
       return true;
     }
     return false;
@@ -207,7 +209,7 @@ class IntervalRefreshPolicy {
       catch (e) {
         // Empty block
       }
-    }, 1000);
+    }, this.duration);
   }
 
   unsubscribe() {
diff --git a/test/index-test.js b/test/index-test.js
index fcc5a64..2895aa8 100644
--- a/test/index-test.js
+++ b/test/index-test.js
@@ -5,10 +5,12 @@ chai.should();
 
 const config = require('../index');
 
-describe('index', () => {
+var clock;
+
+describe('RefreshingConfig', () => {
   it('requires a store', () => {
     (() => {
-      new config.DynamicConfig();
+      new config.RefreshingConfig();
     }).should.throw(Error);
   });
 
@@ -20,6 +22,11 @@ describe('index', () => {
     return target.get('foo').then(value => value.should.equal('bar'));
   });
 
+  it('fails to retrieve a setting if there is no name', () => {
+    const target = new config.RefreshingConfig({});
+    (() => target.get(null)).should.throw(Error);
+  });
+
   it('can set a setting in the store', () => {
     const store = {
       getAll: sinon.stub().returns(Q({ foo: 'bar' })),
@@ -151,6 +158,7 @@ describe('index', () => {
       subscribe: (subscriber) => { this.subscriber = subscriber; },
       refresh: () => this.subscriber.refresh()
     };
+    // TODO: emit on target and config
     const target = new config.RefreshingConfig(store)
       .withExtension(refreshOnDemandPolicy);
     target.getAll()
@@ -158,4 +166,84 @@ describe('index', () => {
 
       });
   });
+
+  it('supports fluent addition of extensions', () => {
+    const target = new config.RefreshingConfig({});
+    target.withExtension(null).should.eq(target);
+    target.withExtension({}).should.eq(target);
+  });
+});
+
+describe('AlwaysRefreshPolicy', () => {
+  it('always returns true', () => {
+    const target = new config.RefreshPolicy.AlwaysRefreshPolicy();
+    target.shouldRefresh().should.true;
+  });
+});
+
+describe('NeverRefreshPolicy', () => {
+  it('always returns false', () => {
+    const target = new config.RefreshPolicy.NeverRefreshPolicy();
+    target.shouldRefresh().should.be.false;
+  });
+});
+
+describe('StaleRefreshPolicy', () => {
+  beforeEach(function () {
+    clock = sinon.useFakeTimers();
+  });
+
+  afterEach(function () {
+    clock.restore();
+  });
+
+  it('refreshes on first call', () => {
+    const target = new config.RefreshPolicy.StaleRefreshPolicy(1000);
+    target.shouldRefresh().should.be.true;
+  });
+  it('refreshes if the interval has passed', () => {
+    const target = new config.RefreshPolicy.StaleRefreshPolicy(1000);
+    target.shouldRefresh();
+    clock.tick(5000);
+    target.shouldRefresh().should.be.true;
+  });
+  it('doesn\'t refresh if the interval hasnn\'t passed', () => {
+    const target = new config.RefreshPolicy.StaleRefreshPolicy(5000);
+    target.shouldRefresh();
+    clock.tick(1000);
+    target.shouldRefresh().should.be.false;
+  });
+});
+
+describe('IntervalRefreshPolicy', () => {
+  beforeEach(function () {
+    clock = sinon.useFakeTimers();
+  });
+
+  afterEach(function () {
+    clock.restore();
+  });
+
+  it('refreshes once the interval has passed', () => {
+    const refreshingConfig = new config.RefreshingConfig({});
+    refreshingConfig.refresh = sinon.stub();
+    const refreshPolicy = new config.RefreshPolicy.IntervalRefreshPolicy(1000);
+    refreshPolicy.subscribe(refreshingConfig);
+    clock.tick(1250);
+    refreshingConfig.refresh.calledOnce.should.be.true;
+    clock.tick(1250);
+    refreshingConfig.refresh.calledTwice.should.be.true;
+    refreshPolicy.unsubscribe();
+  });
+
+  it('stops refreshing once unsubscribed', () => {
+    const refreshingConfig = new config.RefreshingConfig({});
+    refreshingConfig.refresh = sinon.stub();
+    const refreshPolicy = new config.RefreshPolicy.IntervalRefreshPolicy(1000);
+    refreshPolicy.subscribe(refreshingConfig);
+    clock.tick(1250);
+    refreshPolicy.unsubscribe();
+    clock.tick(1250);
+    refreshingConfig.refresh.calledOnce.should.be.true;
+  });
 });
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