Ensure missing SLM policy is handled by client correctly (#4265)

(cherry picked from commit 16ba44e)

Author: codebrain

src/Tests/Tests/XPack/Slm/SlmApiTests.cs

@@ -19,6 +19,7 @@ public class SlmApiTests : CoordinatedIntegrationTestBase<XPackCluster>
 		private const string ExecuteSnapshotLifecycleStep = nameof(ExecuteSnapshotLifecycleStep);
 		private const string GetAllSnapshotLifecycleStep = nameof(GetAllSnapshotLifecycleStep);
 		private const string GetSnapshotLifecycleStep = nameof(GetSnapshotLifecycleStep);
+		private const string GetMissingSnapshotLifecycleStep = nameof(GetMissingSnapshotLifecycleStep);
 		private const string GetSnapshotLifecycleAfterExecuteStep = nameof(GetSnapshotLifecycleAfterExecuteStep);
 		private const string PutSnapshotLifecycleStep = nameof(PutSnapshotLifecycleStep);
 		private const string GetSnapshotLifecycleStats = nameof(GetSnapshotLifecycleStats);
@@ -76,6 +77,20 @@ public SlmApiTests(XPackCluster cluster, EndpointUsage usage) : base(new Coordin
 						(v, c, r) => c.SnapshotLifecycleManagement.PutSnapshotLifecycleAsync(r)
 					)
 			},
+			{
+				GetMissingSnapshotLifecycleStep, u =>
+					u.Calls<GetSnapshotLifecycleDescriptor, GetSnapshotLifecycleRequest, IGetSnapshotLifecycleRequest, GetSnapshotLifecycleResponse>(
+						v => new GetSnapshotLifecycleRequest(v + "-missing")
+						{
+							Human = true
+						},
+						(v, d) => d.PolicyId(v + "-missing").Human(),
+						(v, c, f) => c.SnapshotLifecycleManagement.GetSnapshotLifecycle(f),
+						(v, c, f) => c.SnapshotLifecycleManagement.GetSnapshotLifecycleAsync(f),
+						(v, c, r) => c.SnapshotLifecycleManagement.GetSnapshotLifecycle(r),
+						(v, c, r) => c.SnapshotLifecycleManagement.GetSnapshotLifecycleAsync(r)
+					)
+			},
 			{
 				GetSnapshotLifecycleStep, u =>
 					u.Calls<GetSnapshotLifecycleDescriptor, GetSnapshotLifecycleRequest, IGetSnapshotLifecycleRequest, GetSnapshotLifecycleResponse>(
@@ -166,6 +181,12 @@ [I] public async Task PutSnapshotLifecycleResponse() => await Assert<PutSnapshot
 			r.ApiCall.HttpStatusCode.Should().Be(200);
 		});
 
+		[I] public async Task GetMissingSnapshotLifecycleResponse() => await Assert<GetSnapshotLifecycleResponse>(GetMissingSnapshotLifecycleStep, (v, r) =>
+		{
+			r.IsValid.Should().BeFalse();
+			r.ServerError.Should().NotBeNull();
+		});
+
 		[I] public async Task GetSnapshotLifecycleResponse() => await Assert<GetSnapshotLifecycleResponse>(GetSnapshotLifecycleStep, (v, r) =>
 		{
 			r.IsValid.Should().BeTrue();