Test infrastructure for C# Azure Function testing (#2055)

Add support for function tests and the ability to run them against either real Azure Storage or the Azurite emulator.

See follow-up PR #2032 for actual usage.

src/ApiService/Tests/Fakes/TestContext.cs

@@ -0,0 +1,104 @@
+using System;
+using System.Linq;
+using Microsoft.OneFuzz.Service;
+using Microsoft.OneFuzz.Service.OneFuzzLib.Orm;
+using Async = System.Threading.Tasks;
+
+namespace Tests.Fakes;
+
+
+// TestContext provides a minimal IOnefuzzContext implementation to allow running
+// of functions as unit or integration tests.
+public sealed class TestContext : IOnefuzzContext {
+    public TestContext(ILogTracer logTracer, IStorage storage, string tablePrefix, string accountId) {
+        ServiceConfiguration = new TestServiceConfiguration(tablePrefix, accountId);
+
+        Storage = storage;
+
+        RequestHandling = new RequestHandling(logTracer);
+        TaskOperations = new TaskOperations(logTracer, this);
+        NodeOperations = new NodeOperations(logTracer, this);
+        JobOperations = new JobOperations(logTracer, this);
+        NodeTasksOperations = new NodeTasksOperations(logTracer, this);
+    }
+
+    public TestEvents Events { get; set; } = new();
+
+    // convenience method for test setup
+    public Async.Task InsertAll(params EntityBase[] objs)
+        => Async.Task.WhenAll(
+            objs.Select(x => x switch {
+                Task t => TaskOperations.Insert(t),
+                Node n => NodeOperations.Insert(n),
+                Job j => JobOperations.Insert(j),
+                NodeTasks nt => NodeTasksOperations.Insert(nt),
+                _ => throw new NotImplementedException($"Need to add an TestContext.InsertAll case for {x.GetType()} entities"),
+            }));
+
+    // Implementations:
+
+    IEvents IOnefuzzContext.Events => Events;
+
+    public IServiceConfig ServiceConfiguration { get; }
+
+    public IStorage Storage { get; }
+
+    public IRequestHandling RequestHandling { get; }
+
+    public ITaskOperations TaskOperations { get; }
+    public IJobOperations JobOperations { get; }
+    public INodeOperations NodeOperations { get; }
+    public INodeTasksOperations NodeTasksOperations { get; }
+
+    // -- Remainder not implemented --
+
+    public IConfig Config => throw new System.NotImplementedException();
+
+    public IConfigOperations ConfigOperations => throw new System.NotImplementedException();
+
+    public IContainers Containers => throw new System.NotImplementedException();
+
+    public ICreds Creds => throw new System.NotImplementedException();
+
+    public IDiskOperations DiskOperations => throw new System.NotImplementedException();
+
+    public IExtensions Extensions => throw new System.NotImplementedException();
+
+    public IIpOperations IpOperations => throw new System.NotImplementedException();
+
+
+    public ILogAnalytics LogAnalytics => throw new System.NotImplementedException();
+
+    public INodeMessageOperations NodeMessageOperations => throw new System.NotImplementedException();
+
+    public INotificationOperations NotificationOperations => throw new System.NotImplementedException();
+
+    public IPoolOperations PoolOperations => throw new System.NotImplementedException();
+
+    public IProxyForwardOperations ProxyForwardOperations => throw new System.NotImplementedException();
+
+    public IProxyOperations ProxyOperations => throw new System.NotImplementedException();
+
+    public IQueue Queue => throw new System.NotImplementedException();
+
+    public IReports Reports => throw new System.NotImplementedException();
+
+    public IReproOperations ReproOperations => throw new System.NotImplementedException();
+
+    public IScalesetOperations ScalesetOperations => throw new System.NotImplementedException();
+
+    public IScheduler Scheduler => throw new System.NotImplementedException();
+
+    public ISecretsOperations SecretsOperations => throw new System.NotImplementedException();
+
+    public IUserCredentials UserCredentials => throw new System.NotImplementedException();
+
+    public IVmOperations VmOperations => throw new System.NotImplementedException();
+
+    public IVmssOperations VmssOperations => throw new System.NotImplementedException();
+
+    public IWebhookMessageLogOperations WebhookMessageLogOperations => throw new System.NotImplementedException();
+
+    public IWebhookOperations WebhookOperations => throw new System.NotImplementedException();
+
+}