NCBC-4207: Speed up Stellar unit tests with fast-fail timeouts

Motivation
==========
Couchbase.UnitTests wall-clock had grown to ~98s, dominated by
Stellar tests that point at an unreachable host ("couchbase2://xxx")
and rely on default per-service timeouts to fail. A single QueryAsync
test alone took 75s (default QueryTimeout), and the Test_Schema
theory took 6-12s per case waiting on DNS SRV resolution during
classic bootstrap.

Modification
============
- Added FastFailClusterOptions.WithFastFailTimeouts(FastFailServices),
  a fluent extension on ClusterOptions that applies a short
  KvConnectTimeout plus only the per-service timeouts the caller
  exercises, with an optional DisableDnsSrv flag.
- Wired it into ClusterTests (Query|Analytics for CreateCluster;
  DisableDnsSrv for Test_Schema_Delivers_The_Correct_ICluster_Impl)
  and CollectionTests (Kv for CreateCollection).

Result
======
Unit test wall-clock drops from ~98s to ~9s on net8.0. Tests still
exercise the same failure paths.

Change-Id: I2a934064338348c59c684b3a2a8756c74fbabbde
Reviewed-on: https://review.couchbase.org/c/couchbase-net-client/+/245844
Tested-by: Build Bot <build@couchbase.com>
Reviewed-by: Jeffry Morris <jeffrymorris@gmail.com>

Author: davidkelly

tests/Couchbase.UnitTests/Stellar/ClusterTests.cs

@@ -17,6 +17,7 @@
 using Couchbase.Stellar.Core;
 using Couchbase.Stellar.Search;
 using Couchbase.Stellar.Util;
+using Couchbase.UnitTests.Utils;
 using Grpc.Core;
 using Grpc.Net.Client;
 using Moq;
@@ -109,7 +110,9 @@ public async Task Test_Schema_Delivers_The_Correct_ICluster_Impl(string connecti
 #pragma warning disable CS0618 // Type or member is obsolete
           var options = new ClusterOptions().WithCredentials("Administrator", "password");
 #pragma warning restore CS0618 // Type or member is obsolete
-          options.KvConnectTimeout = TimeSpan.FromMilliseconds(1);
+          // Classic schemes do DNS SRV lookup during bootstrap which adds several seconds
+          // before bootstrap gives up against the unreachable "xxx" host.
+          options.WithFastFailTimeouts(FastFailServices.DisableDnsSrv);
           var cluster = await Cluster.ConnectAsync(connectionString,options);
 
           Assert.IsType(type, cluster);
@@ -121,7 +124,9 @@ public async Task<ICluster> CreateCluster()
 
 #pragma warning disable CS0618 // Type or member is obsolete
           var options = new ClusterOptions().WithCredentials("Administrator", "password");
-          options.KvConnectTimeout = TimeSpan.FromMilliseconds(1);
+          // Tests using this helper exercise Query/Analytics; shorten those so the failing op
+          // surfaces a CouchbaseException quickly instead of waiting the default 75s.
+          options.WithFastFailTimeouts(FastFailServices.Query | FastFailServices.Analytics);
           options.HttpIgnoreRemoteCertificateMismatch = true;
           options.KvIgnoreRemoteCertificateNameMismatch = true;
 #pragma warning restore CS0618 // Type or member is obsolete

tests/Couchbase.UnitTests/Stellar/KeyValue/CollectionTests.cs

@@ -8,6 +8,7 @@
 using Couchbase.KeyValue.RangeScan;
 using Couchbase.Stellar;
 using Couchbase.Stellar.Util;
+using Couchbase.UnitTests.Utils;
 using Xunit;
 
 namespace Couchbase.UnitTests.Stellar.KeyValue;
@@ -154,7 +155,9 @@ private async Task<ICouchbaseCollection> CreateCollection()
 #pragma warning disable CS0618 // Type or member is obsolete
         var options = new ClusterOptions().WithCredentials("Administrator", "password");
 #pragma warning restore CS0618 // Type or member is obsolete
-        options.KvConnectTimeout = TimeSpan.FromMilliseconds(1);
+        // All tests using this helper drive KV ops against an unreachable host; without a short
+        // KvTimeout each failing op would block on the default 2.5s.
+        options.WithFastFailTimeouts(FastFailServices.Kv);
 
         var cluster = await Cluster.ConnectAsync(connectionString, options);
         var bucket = await cluster.BucketAsync("default");

tests/Couchbase.UnitTests/Utils/FastFailClusterOptions.cs

@@ -0,0 +1,40 @@
+using System;
+
+namespace Couchbase.UnitTests.Utils;
+
+[Flags]
+internal enum FastFailServices
+{
+    None = 0,
+    Kv = 1 << 0,
+    Query = 1 << 1,
+    Analytics = 1 << 2,
+    Search = 1 << 3,
+    View = 1 << 4,
+    Management = 1 << 5,
+    DisableDnsSrv = 1 << 6,
+}
+
+internal static class FastFailClusterOptions
+{
+    private static readonly TimeSpan FastFail = TimeSpan.FromMilliseconds(100);
+
+    // Unit tests that deliberately point at an unreachable host need short timeouts so the
+    // failing op surfaces a CouchbaseException quickly instead of waiting the default
+    // per-service timeout (75s for Query/Analytics/Search/View/Management, 2.5s for KV).
+    // Classic-scheme bootstrap additionally does DNS SRV resolution that adds several
+    // seconds. This extension applies only the knobs the caller actually exercises so each
+    // test surface is explicit.
+    public static ClusterOptions WithFastFailTimeouts(this ClusterOptions options, FastFailServices services)
+    {
+        options.KvConnectTimeout = TimeSpan.FromMilliseconds(1);
+        if ((services & FastFailServices.DisableDnsSrv) != 0) options.EnableDnsSrvResolution = false;
+        if ((services & FastFailServices.Kv) != 0) options.KvTimeout = FastFail;
+        if ((services & FastFailServices.Query) != 0) options.QueryTimeout = FastFail;
+        if ((services & FastFailServices.Analytics) != 0) options.AnalyticsTimeout = FastFail;
+        if ((services & FastFailServices.Search) != 0) options.SearchTimeout = FastFail;
+        if ((services & FastFailServices.View) != 0) options.ViewTimeout = FastFail;
+        if ((services & FastFailServices.Management) != 0) options.ManagementTimeout = FastFail;
+        return options;
+    }
+}