improve test coverage: InMemoryExporter & IDeferredMeterProviderBuilder

test/OpenTelemetry.Extensions.Hosting.Tests/InMemoryExporterMetricsExtensionsTests.cs

@@ -0,0 +1,112 @@
+// <copyright file="InMemoryExporterMetricsExtensionsTests.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+#if NETCOREAPP3_1_OR_GREATER
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Metrics;
+using System.Net;
+using System.Threading.Tasks;
+
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Hosting;
+using Microsoft.AspNetCore.TestHost;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+
+using OpenTelemetry.Metrics;
+using OpenTelemetry.Tests;
+
+using Xunit;
+
+namespace OpenTelemetry.Extensions.Hosting.Tests
+{
+    /// <summary>
+    /// These tests verify that <see cref="InMemoryExporter"/> works with <see cref="IDeferredMeterProviderBuilder"/>.
+    /// </summary>
+    public class InMemoryExporterMetricsExtensionsTests
+    {
+        [Fact]
+        public async Task DeferredMeterProviderBuilder_WithMetric()
+        {
+            var meterName = Utils.GetCurrentMethodName();
+            var exportedItems = new List<Metric>();
+
+            await RunMetricsTest(
+                configure: builder => builder
+                    .AddMeter(meterName)
+                    .AddInMemoryExporter(exportedItems),
+                testAction: () =>
+                {
+                    using var meter = new Meter(meterName);
+                    var counter = meter.CreateCounter<long>("meter");
+                    counter.Add(10);
+                });
+
+            Assert.Single(exportedItems);
+            var metricPointsEnumerator = exportedItems[0].GetMetricPoints().GetEnumerator();
+            Assert.True(metricPointsEnumerator.MoveNext());
+            Assert.Equal(10, metricPointsEnumerator.Current.GetSumLong());
+        }
+
+        [Fact]
+        public async Task DeferredMeterProviderBuilder_WithMetricSnapshot()
+        {
+            var meterName = Utils.GetCurrentMethodName();
+            var exportedItems = new List<MetricSnapshot>();
+
+            await RunMetricsTest(
+                configure: builder => builder
+                    .AddMeter(meterName)
+                    .AddInMemoryExporter(exportedItems),
+                testAction: () =>
+                {
+                    using var meter = new Meter(meterName);
+                    var counter = meter.CreateCounter<long>("meter");
+                    counter.Add(10);
+                });
+
+            Assert.Single(exportedItems);
+            Assert.Equal(10, exportedItems[0].MetricPoints[0].GetSumLong());
+        }
+
+        private static async Task RunMetricsTest(Action<MeterProviderBuilder> configure, Action testAction)
+        {
+            using var host = await new HostBuilder()
+               .ConfigureWebHost(webBuilder => webBuilder
+                   .UseTestServer()
+                   .ConfigureServices(services => services.AddOpenTelemetryMetrics(configure))
+                   .Configure(app => app.Run(httpContext =>
+                   {
+                       testAction.Invoke();
+
+                       var meterProvider = app.ApplicationServices.GetRequiredService<MeterProvider>();
+                       meterProvider.ForceFlush();
+
+                       return Task.CompletedTask;
+                   })))
+               .StartAsync();
+
+            using var response = await host.GetTestClient().GetAsync($"/{nameof(RunMetricsTest)}").ConfigureAwait(false);
+
+            Assert.Equal(HttpStatusCode.OK, response.StatusCode);
+
+            await host.StopAsync().ConfigureAwait(false);
+        }
+    }
+}
+#endif

test/OpenTelemetry.Extensions.Hosting.Tests/OpenTelemetry.Extensions.Hosting.Tests.csproj

@@ -8,8 +8,11 @@
 
   <ItemGroup>
     <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.Extensions.Hosting\OpenTelemetry.Extensions.Hosting.csproj" />
-    <Compile Include="$(RepoRoot)\test\OpenTelemetry.Tests\Shared\EventSourceTestHelper.cs" Link="EventSourceTestHelper.cs" />
-    <Compile Include="$(RepoRoot)\test\OpenTelemetry.Tests\Shared\TestEventListener.cs" Link="TestEventListener.cs" />
+    <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.Exporter.InMemory\OpenTelemetry.Exporter.InMemory.csproj" />
+
+    <Compile Include="$(RepoRoot)\test\OpenTelemetry.Tests\Shared\EventSourceTestHelper.cs" Link="Includes\EventSourceTestHelper.cs" />
+    <Compile Include="$(RepoRoot)\test\OpenTelemetry.Tests\Shared\TestEventListener.cs" Link="Includes\TestEventListener.cs" />
+    <Compile Include="$(RepoRoot)\test\OpenTelemetry.Tests\Shared\Utils.cs" Link="Includes\Utils.cs" />
   </ItemGroup>
 
   <ItemGroup>
@@ -23,4 +26,12 @@
     <DotNetCliToolReference Include="dotnet-xunit" Version="$(DotNetXUnitCliVer)" />
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="$(MicrosoftExtensionsHostingPkgVer)" />
   </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'net6.0'">
+    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="6.0.0" />
+  </ItemGroup>
+
+  <ItemGroup Condition="'$(TargetFramework)' == 'netcoreapp3.1'">
+    <PackageReference Include="Microsoft.AspNetCore.TestHost" Version="3.1.0" />
+  </ItemGroup>
 </Project>