add tests for weak.get()

test/get.js

@@ -0,0 +1,28 @@
+var assert = require('assert');
+var weak = require('../');
+
+describe('weak.get()', function () {
+
+  afterEach(gc);
+
+  it('should return the target if it is still accessible', function () {
+    var obj = {};
+    var r = weak(obj);
+    assert.equal(obj, weak.get(r));
+  });
+
+  it('should return undefined after the target is gc\'d', function () {
+    var r = weak({});
+    gc();
+    assert.equal(undefined, weak.get(r));
+  });
+
+  it('should not crash inside garbage collection callback', function () {
+    var result;
+    var r = weak({}, function () {
+      result = typeof(weak.get(r));
+    });
+    gc();
+  });
+
+});