public async Task ValidateNegativeNotAwaitedScenario()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
Task task1 = asyncCache.GetAsync(
"test",
async(_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
throw new NotFoundException("testNotFoundException");
},
(_) => false);
try
{
await asyncCache.GetAsync(
"test",
(_) => throw new BadRequestException("testBadRequestException"),
(_) => false);
Assert.Fail("Should have thrown a NotFoundException");
}
catch (NotFoundException)
{
}
await task1;
}
public async Task ValidateMultipleBackgroundRefreshesScenario()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
string expectedValue = "ResponseValue";
string response = await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
return(expectedValue);
},
(_) => false);
Assert.AreEqual(expectedValue, response);
for (int i = 0; i < 10; i++)
{
string forceRefreshResponse = await asyncCache.GetAsync(
key : "test",
singleValueInitFunc : async(_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
return(expectedValue + i);
},
forceRefresh : (_) => true);
Assert.AreEqual(expectedValue + i, forceRefreshResponse);
}
}
public async Task ValidateCacheValueIsRemovedAfterException()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
string result = await asyncCache.GetAsync(
"test",
() => Task.FromResult("test2"),
false,
null);
Assert.AreEqual("test2", result);
string cachedResults = await asyncCache.GetAsync(
"test",
() => throw new Exception("should not refresh"),
false,
null);
Assert.AreEqual("test2", cachedResults);
// Simulate a slow connection on a refresh operation. The async call will
// be blocked to verify a read can still be done using the stale value.
bool delayException = true;
Task task = Task.Run(async() =>
{
try
{
await asyncCache.GetAsync(
"test",
async() =>
{
while (delayException)
{
await Task.Delay(TimeSpan.FromMilliseconds(1));
}
throw new NotFoundException("testNotFoundException");
},
true,
null);
Assert.Fail();
}
catch (NotFoundException nfe)
{
Assert.IsTrue(nfe.Message.Contains("testNotFoundException"), $"NotFoundException message is missing: {nfe.Message}");
}
});
cachedResults = await asyncCache.GetAsync(
"test",
() => throw new Exception("should not refresh"),
false,
null);
Assert.AreEqual("test2", cachedResults);
delayException = false;
await task;
}
public async Task ValidateNegativeScenario(bool forceRefresh)
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
await asyncCache.GetAsync(
"test",
() => throw new NotFoundException("testNotFoundException"),
forceRefresh,
null);
}
public async Task ValidateAsyncCacheNonBlocking()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
string result = await asyncCache.GetAsync(
"test",
() => Task.FromResult("test2"),
false,
(x, y) => throw new Exception("Should not be called since there is no refresh"));
string cachedResults = await asyncCache.GetAsync(
"test",
() => throw new Exception("should not refresh"),
false,
(x, y) => throw new Exception("Should not be called since there is no refresh"));
string oldValue = null;
string newValue = null;
Task <string> updateTask = asyncCache.GetAsync(
key: "test",
singleValueInitFunc: async() =>
{
await Task.Delay(TimeSpan.FromSeconds(1));
return("Test3");
},
forceRefresh: true,
callBackOnForceRefresh: (x, y) => { oldValue = x; newValue = y; });
Stopwatch concurrentOperationStopwatch = Stopwatch.StartNew();
string concurrentUpdateTask = await asyncCache.GetAsync(
"test",
() => throw new Exception("should not refresh"),
false,
(x, y) => throw new Exception("Should not be called since there is no refresh"));
Assert.AreEqual("test2", result);
concurrentOperationStopwatch.Stop();
Assert.IsTrue(concurrentOperationStopwatch.Elapsed.TotalMilliseconds < 500);
result = await updateTask;
Assert.AreEqual("Test3", result);
Assert.AreEqual(oldValue, "test2", "The call back was not done.");
Assert.AreEqual(newValue, "Test3", "The call back was not done.");
}
public async Task ValidateNegativeScenario(bool forceRefresh)
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
throw new NotFoundException("testNotFoundException");
},
(_) => forceRefresh);
}
public async Task ValidateConcurrentCreateWithFailureAsyncCacheNonBlocking()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
int totalLazyCalls = 0;
Random random = new Random();
List <Task> tasks = new List <Task>();
for (int i = 0; i < 50; i++)
{
// Insert a random delay to simulate multiple request coming at different times
await Task.Delay(random.Next(0, 5));
tasks.Add(Task.Run(async() =>
{
try
{
await asyncCache.GetAsync(
"key",
async() =>
{
Interlocked.Increment(ref totalLazyCalls);
await Task.Delay(random.Next(0, 3));
throw new NotFoundException("test");
},
forceRefresh: false,
(x, y) => throw new Exception("Should not be called since there is no refresh"));
Assert.Fail();
}
catch (DocumentClientException dce)
{
Assert.AreEqual(dce.StatusCode, HttpStatusCode.NotFound);
}
}));
}
await Task.WhenAll(tasks);
Assert.IsTrue(totalLazyCalls > 1, $"Expected multiple async refresh call. TotalCount {totalLazyCalls}");
}
public async Task ValidateConcurrentCreateAsyncCacheNonBlocking()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
int totalLazyCalls = 0;
List <Task> tasks = new List <Task>();
for (int i = 0; i < 500; i++)
{
tasks.Add(Task.Run(() => asyncCache.GetAsync(
key: "key",
singleValueInitFunc: (_) =>
{
Interlocked.Increment(ref totalLazyCalls);
return(Task.FromResult("Test"));
},
forceRefresh: (_) => false)));
}
await Task.WhenAll(tasks);
Assert.AreEqual(1, totalLazyCalls);
}
public async Task ValidateConcurrentCreateAsyncCacheNonBlocking()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
int totalLazyCalls = 0;
List <Task> tasks = new List <Task>();
for (int i = 0; i < 500; i++)
{
tasks.Add(Task.Run(() => asyncCache.GetAsync(
"key",
() =>
{
Interlocked.Increment(ref totalLazyCalls);
return(Task.FromResult("Test"));
},
forceRefresh: false,
(x, y) => throw new Exception("Should not be called since there is no refresh"))));
}
await Task.WhenAll(tasks);
Assert.AreEqual(1, totalLazyCalls);
}
public async Task ValidateExceptionScenariosCacheNonBlocking()
{
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
int totalLazyCalls = 0;
try
{
await asyncCache.GetAsync(
"key",
async() =>
{
// Use a dummy await to make it simulate a real async network call
await Task.CompletedTask;
Interlocked.Increment(ref totalLazyCalls);
throw new DocumentClientException("test", HttpStatusCode.NotFound, SubStatusCodes.Unknown);
},
forceRefresh : false,
null);
Assert.Fail();
}
catch (DocumentClientException dce)
{
Assert.AreEqual(dce.StatusCode, HttpStatusCode.NotFound);
Assert.AreEqual(1, totalLazyCalls);
}
// Verify cache removes the Task that hit the exception and the new task
// is used to try to get the value.
totalLazyCalls = 0;
try
{
await asyncCache.GetAsync(
"key",
async() =>
{
// Use a dummy await to make it simulate a real async network call
await Task.CompletedTask;
Interlocked.Increment(ref totalLazyCalls);
throw new DocumentClientException("test", HttpStatusCode.BadRequest, SubStatusCodes.Unknown);
},
forceRefresh : false,
null);
Assert.Fail();
}
catch (DocumentClientException dce)
{
Assert.AreEqual(dce.StatusCode, HttpStatusCode.BadRequest);
Assert.AreEqual(1, totalLazyCalls);
}
// Verify cache success after failures
totalLazyCalls = 0;
string result = await asyncCache.GetAsync(
"key",
async() =>
{
// Use a dummy await to make it simulate a real async network call
await Task.CompletedTask;
Interlocked.Increment(ref totalLazyCalls);
return("Test3");
},
forceRefresh : false,
null);
Assert.AreEqual(1, totalLazyCalls);
Assert.AreEqual("Test3", result);
}
public async Task ValidateNotFoundOnBackgroundRefreshRemovesFromCacheScenario()
{
string value1 = "Response1Value";
AsyncCacheNonBlocking <string, string> asyncCache = new AsyncCacheNonBlocking <string, string>();
string response1 = await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
return(value1);
},
(staleValue) =>
{
Assert.AreEqual(null, staleValue);
return(false);
});
Assert.AreEqual(value1, response1);
string response2 = await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
throw new Exception("Should use cached value");
},
(staleValue) =>
{
Assert.AreEqual(value1, staleValue);
return(false);
});
Assert.AreEqual(value1, response2);
NotFoundException notFoundException = new NotFoundException("Item was deleted");
try
{
await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
throw notFoundException;
},
(_) => true);
Assert.Fail("Should have thrown a NotFoundException");
}
catch (NotFoundException exception)
{
Assert.AreEqual(notFoundException, exception);
}
string valueAfterNotFound = "response4Value";
string response4 = await asyncCache.GetAsync(
"test",
async (_) =>
{
await Task.Delay(TimeSpan.FromMilliseconds(5));
return(valueAfterNotFound);
},
(_) => false);
Assert.AreEqual(valueAfterNotFound, response4);
}