Integration test for GCRA

Author: mgravell

tests/RedisConfigs/.docker/Redis/Dockerfile

@@ -1,4 +1,4 @@
-FROM redislabs/client-libs-test:8.6.0
+FROM redislabs/client-libs-test:unstable-23321515778-debian
 
 COPY --from=configs ./Basic /data/Basic/
 COPY --from=configs ./Failover /data/Failover/

tests/StackExchange.Redis.Tests/GcraIntegrationTests.cs

@@ -0,0 +1,48 @@
+using System;
+using System.Threading.Tasks;
+using Xunit;
+
+namespace StackExchange.Redis.Tests;
+
+[RunPerProtocol]
+public class GcraIntegrationTests(ITestOutputHelper output, SharedConnectionFixture fixture) : TestBase(output, fixture)
+{
+    [Fact(Timeout = 5000)]
+    public async Task GcraRateLimit_SmokeTest()
+    {
+        await using var conn = Create(require: new Version(8, 8, 0));
+        var db = conn.GetDatabase();
+        var key = Me();
+        db.KeyDelete(key, CommandFlags.FireAndForget);
+        for (int i = 0; i < 15; i++)
+        {
+            var result = await db.StringGcraRateLimitAsync(key, maxBurst: 10, requestsPerPeriod: 10, periodSeconds: 1.0);
+            Log($"Run {i}: Limited: {result.Limited}, Available: {result.AvailableRequests}, RetryAfter: {result.RetryAfterSeconds}, FullBurstAfter: {result.FullBurstAfterSeconds}, MaxRequests: {result.MaxRequests}");
+            if (i <= 10)
+            {
+                Assert.False(result.Limited, $"run {i}");
+            }
+            else
+            {
+                Assert.True(result.Limited, $"run {i}");
+            }
+            Assert.Equal(11, result.MaxRequests);
+            Assert.Equal(Math.Max(0, 10 - i), result.AvailableRequests);
+            if (result.Limited)
+            {
+                Assert.True(result.RetryAfterSeconds > 0);
+            }
+            else
+            {
+                Assert.Equal(-1, result.RetryAfterSeconds);
+            }
+            Assert.True(result.FullBurstAfterSeconds > 0);
+        }
+        await db.TryAcquireGcraAsync(
+            key,
+            maxBurst: 10,
+            requestsPerPeriod: 10,
+            allow: TimeSpan.FromSeconds(5),
+            cancellationToken: TestContext.Current.CancellationToken);
+    }
+}