public void TestUnavailableValue()
{
var funcCalled = false;
Action<Action> assertThatFuncIsCalled = action =>
{
Assert.IsFalse(funcCalled);
action();
Assert.IsTrue(funcCalled);
funcCalled = false;
};
var importantNumber = 42;
var proxy = new LazyProxy<int, string>(x =>
{
funcCalled = true;
return importantNumber < 50 ? null : x.ToString();
});
Assert.AreEqual(null, proxy.GetValue());
proxy.SetData(3);
assertThatFuncIsCalled(() => Assert.AreEqual(null, proxy.GetValue()));
for (int i = 0; i < LazyProxy<int, string>.NULL_WAIT_RETRY_COUNT; i++)
Assert.AreEqual(null, proxy.GetValue());
importantNumber = 69;
assertThatFuncIsCalled(() => Assert.AreEqual("3", proxy.GetValue()));
importantNumber = 0; // doesn't affect GetValue any more
Assert.AreEqual("3", proxy.GetValue());
Assert.IsFalse(funcCalled);
}
public void TestLazyString()
{
var proxy = new LazyProxy<int, string>(x => new System.Text.StringBuilder().Append('x', x).ToString());
Assert.AreEqual(null, proxy.GetValue());
proxy.SetData(5);
string proxyValue = proxy;
Assert.AreEqual("xxxxx", proxyValue);
}
public void TestEager()
{
var proxy = new LazyProxy<int, string>("6");
Assert.AreEqual("6", proxy.GetValue());
Assert.Throws<InvalidOperationException>(() => proxy.SetData(42));
}
