Test improvements

src/OpenTelemetry.Exporter.Prometheus/AssemblyInfo.cs

@@ -13,6 +13,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 // </copyright>
+
 using System.Runtime.CompilerServices;
 
 #if SIGNED

src/OpenTelemetry.Exporter.Prometheus/Implementation/PrometheusCollectionManager.cs

@@ -203,7 +203,7 @@ private ExportResult OnCollect(Batch<Metric> metrics)
                     }
                 }
 
-                this.previousDataView = new ArraySegment<byte>(this.buffer, 0, cursor);
+                this.previousDataView = new ArraySegment<byte>(this.buffer, 0, Math.Max(cursor - 1, 0));
                 return ExportResult.Success;
             }
             catch (Exception)

src/OpenTelemetry.Exporter.Prometheus/Implementation/PrometheusSerializerExt.cs

@@ -25,27 +25,6 @@ internal static partial class PrometheusSerializer
     {
         private static readonly string[] MetricTypes = new string[] { "untyped", "counter", "gauge", "histogram", "summary" };
 
-        public static int WriteMetrics(byte[] buffer, int cursor, Batch<Metric> metrics)
-        {
-            var spacing = false;
-
-            foreach (var metric in metrics)
-            {
-                if (spacing)
-                {
-                    buffer[cursor++] = ASCII_LINEFEED;
-                }
-                else
-                {
-                    spacing = true;
-                }
-
-                cursor = WriteMetric(buffer, cursor, metric);
-            }
-
-            return cursor;
-        }
-
         public static int WriteMetric(byte[] buffer, int cursor, Metric metric)
         {
             if (!string.IsNullOrWhiteSpace(metric.Description))
@@ -199,6 +178,8 @@ public static int WriteMetric(byte[] buffer, int cursor, Metric metric)
                 }
             }
 
+            buffer[cursor++] = ASCII_LINEFEED;
+
             return cursor;
         }
     }

test/OpenTelemetry.Exporter.Prometheus.Tests/OpenTelemetry.Exporter.Prometheus.Tests.csproj

@@ -19,6 +19,7 @@
   </ItemGroup>
 
   <ItemGroup>
+    <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.Exporter.InMemory\OpenTelemetry.Exporter.InMemory.csproj" />
     <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.Exporter.Prometheus\OpenTelemetry.Exporter.Prometheus.csproj" />
     <ProjectReference Include="$(RepoRoot)\src\OpenTelemetry.Extensions.Hosting\OpenTelemetry.Extensions.Hosting.csproj" />
   </ItemGroup>

test/OpenTelemetry.Exporter.Prometheus.Tests/PrometheusExporterHttpServerTests.cs

@@ -89,8 +89,6 @@ public async Task PrometheusExporterHttpServerIntegration()
                 new KeyValuePair<string, object>("key2", "value2"),
             };
 
-            var beginTimestamp = DateTimeOffset.Now.ToUnixTimeMilliseconds();
-
             var counter = meter.CreateCounter<double>("counter_double");
             counter.Add(100.18D, tags);
             counter.Add(0.99D, tags);
@@ -99,29 +97,11 @@ public async Task PrometheusExporterHttpServerIntegration()
 
             using var response = await client.GetAsync($"{address}metrics").ConfigureAwait(false);
 
-            var endTimestamp = DateTimeOffset.Now.ToUnixTimeMilliseconds();
-
             Assert.Equal(HttpStatusCode.OK, response.StatusCode);
 
-            string content = await response.Content.ReadAsStringAsync().ConfigureAwait(false);
-
-            string[] lines = content.Split('\n');
-
-            Assert.Equal(
-                $"# TYPE counter_double counter",
-                lines[0]);
-
-            Assert.Contains(
-                $"counter_double{{key1=\"value1\",key2=\"value2\"}} 101.17",
-                lines[1]);
-
-            var index = content.LastIndexOf(' ');
-
-            Assert.Equal('\n', content[content.Length - 1]);
-
-            var timestamp = long.Parse(content.Substring(index, content.Length - index - 1));
-
-            Assert.True(beginTimestamp <= timestamp && timestamp <= endTimestamp);
+            Assert.Matches(
+                "^# TYPE counter_double counter\ncounter_double{key1='value1',key2='value2'} 101.17 \\d+\n$".Replace('\'', '"'),
+                await response.Content.ReadAsStringAsync().ConfigureAwait(false));
         }
     }
 }

test/OpenTelemetry.Exporter.Prometheus.Tests/PrometheusSerializerTests.cs

@@ -0,0 +1,142 @@
+// <copyright file="PrometheusSerializerTests.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>
+
+using System;
+using System.Collections.Generic;
+using System.Diagnostics.Metrics;
+using System.Text;
+using OpenTelemetry.Metrics;
+using OpenTelemetry.Tests;
+using Xunit;
+
+namespace OpenTelemetry.Exporter.Prometheus.Tests
+{
+    public sealed class PrometheusSerializerTests
+    {
+        [Fact]
+        public void ZeroDimension()
+        {
+            var buffer = new byte[85000];
+            var metrics = new List<Metric>();
+
+            using var meter = new Meter(Utils.GetCurrentMethodName());
+            using var provider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meter.Name)
+                .AddInMemoryExporter(metrics)
+                .Build();
+
+            meter.CreateObservableGauge("test_gauge", () => 123);
+
+            provider.ForceFlush();
+
+            var cursor = PrometheusSerializer.WriteMetric(buffer, 0, metrics[0]);
+            Assert.Matches(
+                "^# TYPE test_gauge gauge\ntest_gauge 123 \\d+\n$",
+                Encoding.UTF8.GetString(buffer, 0, cursor));
+        }
+
+        [Fact]
+        public void ZeroDimensionWithDescription()
+        {
+            var buffer = new byte[85000];
+            var metrics = new List<Metric>();
+
+            using var meter = new Meter(Utils.GetCurrentMethodName());
+            using var provider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meter.Name)
+                .AddInMemoryExporter(metrics)
+                .Build();
+
+            meter.CreateObservableGauge("test_gauge", () => 123, description: "Hello, world!");
+
+            provider.ForceFlush();
+
+            var cursor = PrometheusSerializer.WriteMetric(buffer, 0, metrics[0]);
+            Assert.Matches(
+                "^# HELP test_gauge Hello, world!\n# TYPE test_gauge gauge\ntest_gauge 123 \\d+\n$",
+                Encoding.UTF8.GetString(buffer, 0, cursor));
+        }
+
+        [Fact]
+        public void ZeroDimensionWithUnit()
+        {
+            var buffer = new byte[85000];
+            var metrics = new List<Metric>();
+
+            using var meter = new Meter(Utils.GetCurrentMethodName());
+            using var provider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meter.Name)
+                .AddInMemoryExporter(metrics)
+                .Build();
+
+            meter.CreateObservableGauge("test_gauge", () => 123, unit: "seconds");
+
+            provider.ForceFlush();
+
+            var cursor = PrometheusSerializer.WriteMetric(buffer, 0, metrics[0]);
+            Assert.Matches(
+                "^# TYPE test_gauge_seconds gauge\ntest_gauge_seconds 123 \\d+\n$",
+                Encoding.UTF8.GetString(buffer, 0, cursor));
+        }
+
+        [Fact]
+        public void OneDimension()
+        {
+            var buffer = new byte[85000];
+            var metrics = new List<Metric>();
+
+            using var meter = new Meter(Utils.GetCurrentMethodName());
+            using var provider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meter.Name)
+                .AddInMemoryExporter(metrics)
+                .Build();
+
+            var counter = meter.CreateCounter<long>("test_counter");
+            counter.Add(123, new KeyValuePair<string, object>("tagKey", "tagValue"));
+
+            provider.ForceFlush();
+
+            var cursor = PrometheusSerializer.WriteMetric(buffer, 0, metrics[0]);
+            Assert.Matches(
+                "^# TYPE test_counter counter\ntest_counter{tagKey='tagValue'} 123 \\d+\n$".Replace('\'', '"'),
+                Encoding.UTF8.GetString(buffer, 0, cursor));
+        }
+
+        [Fact]
+        public void DoubleInfinites()
+        {
+            var buffer = new byte[85000];
+            var metrics = new List<Metric>();
+
+            using var meter = new Meter(Utils.GetCurrentMethodName());
+            using var provider = Sdk.CreateMeterProviderBuilder()
+                .AddMeter(meter.Name)
+                .AddInMemoryExporter(metrics)
+                .Build();
+
+            var counter = meter.CreateCounter<double>("test_counter");
+            counter.Add(1.0E308);
+            counter.Add(1.0E308);
+
+            provider.ForceFlush();
+
+            var cursor = PrometheusSerializer.WriteMetric(buffer, 0, metrics[0]);
+            Assert.Matches(
+                "^# TYPE test_counter counter\ntest_counter \\+Inf \\d+\n$",
+                Encoding.UTF8.GetString(buffer, 0, cursor));
+        }
+    }
+}

test/OpenTelemetry.Tests/Metrics/InMemoryExporterTests.cs

@@ -27,28 +27,25 @@ public class InMemoryExporterTests
         [Fact(Skip = "To be run after https://github.com/open-telemetry/opentelemetry-dotnet/issues/2361 is fixed")]
         public void InMemoryExporterShouldDeepCopyMetricPoints()
         {
-            var meter = new Meter(Utils.GetCurrentMethodName());
-
-            var exportedItems = new List<Metric>();
-            using var inMemoryReader = new BaseExportingMetricReader(new InMemoryExporter<Metric>(exportedItems))
-            {
-                PreferredAggregationTemporality = AggregationTemporality.Delta,
-            };
+            var metrics = new List<Metric>();
 
+            using var meter = new Meter(Utils.GetCurrentMethodName());
             using var meterProvider = Sdk.CreateMeterProviderBuilder()
-            .AddMeter(meter.Name)
-            .AddReader(inMemoryReader)
-            .Build();
+                .AddMeter(meter.Name)
+                .AddReader(new BaseExportingMetricReader(new InMemoryExporter<Metric>(metrics))
+                {
+                    PreferredAggregationTemporality = AggregationTemporality.Delta,
+                })
+                .Build();
 
             var counter = meter.CreateCounter<long>("meter");
 
             // Emit 10 for the MetricPoint with a single key-vaue pair: ("tag1", "value1")
             counter.Add(10, new KeyValuePair<string, object>("tag1", "value1"));
 
-            // Pull metric data from AggregatorStore
-            inMemoryReader.Collect();
+            meterProvider.ForceFlush();
 
-            var metric = exportedItems[0]; // Only one Metric object is added to the collection at this point
+            var metric = metrics[0]; // Only one Metric object is added to the collection at this point
             var metricPointsEnumerator = metric.GetMetricPoints().GetEnumerator();
             Assert.True(metricPointsEnumerator.MoveNext()); // One MetricPoint is emitted for the Metric
             ref var metricPointForFirstExport = ref metricPointsEnumerator.Current;
@@ -57,10 +54,9 @@ public void InMemoryExporterShouldDeepCopyMetricPoints()
             // Emit 25 for the MetricPoint with a single key-vaue pair: ("tag1", "value1")
             counter.Add(25, new KeyValuePair<string, object>("tag1", "value1"));
 
-            // Pull metric data from AggregatorStore
-            inMemoryReader.Collect();
+            meterProvider.ForceFlush();
 
-            metric = exportedItems[1]; // Second Metric object is added to the collection at this point
+            metric = metrics[1]; // Second Metric object is added to the collection at this point
             metricPointsEnumerator = metric.GetMetricPoints().GetEnumerator();
             Assert.True(metricPointsEnumerator.MoveNext()); // One MetricPoint is emitted for the Metric
             var metricPointForSecondExport = metricPointsEnumerator.Current;

test/OpenTelemetry.Tests/Metrics/MetricAPITest.cs

@@ -594,7 +594,7 @@ public void MultithreadedDoubleCounterTest()
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.InvalidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.InvalidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void InstrumentWithInvalidNameIsIgnoredTest(string instrumentName)
         {
             var exportedItems = new List<Metric>();
@@ -616,7 +616,7 @@ public void InstrumentWithInvalidNameIsIgnoredTest(string instrumentName)
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.ValidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.ValidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void InstrumentWithValidNameIsExportedTest(string name)
         {
             var exportedItems = new List<Metric>();

test/OpenTelemetry.Tests/Metrics/MetricsTestData.cs → test/OpenTelemetry.Tests/Metrics/MetricTestData.cs

@@ -1,4 +1,4 @@
-// <copyright file="MetricsTestData.cs" company="OpenTelemetry Authors">
+// <copyright file="MetricTestData.cs" company="OpenTelemetry Authors">
 // Copyright The OpenTelemetry Authors
 //
 // Licensed under the Apache License, Version 2.0 (the "License");
@@ -18,7 +18,7 @@
 
 namespace OpenTelemetry.Metrics.Tests
 {
-    public class MetricsTestData
+    public class MetricTestData
     {
         public static IEnumerable<object[]> InvalidInstrumentNames
            => new List<object[]>

test/OpenTelemetry.Tests/Metrics/MetricViewTests.cs

@@ -54,7 +54,7 @@ public void ViewToRenameMetric()
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.InvalidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.InvalidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void AddViewWithInvalidNameThrowsArgumentException(string viewNewName)
         {
             var exportedItems = new List<Metric>();
@@ -93,7 +93,7 @@ public void AddViewWithNullMetricStreamConfigurationThrowsArgumentnullException(
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.InvalidHistogramBounds), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.InvalidHistogramBounds), MemberType = typeof(MetricTestData))]
         public void AddViewWithInvalidHistogramBoundsThrowsArgumentException(double[] bounds)
         {
             var ex = Assert.Throws<ArgumentException>(() => Sdk.CreateMeterProviderBuilder()
@@ -103,7 +103,7 @@ public void AddViewWithInvalidHistogramBoundsThrowsArgumentException(double[] bo
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.ValidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.ValidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void ViewWithValidNameExported(string viewNewName)
         {
             var exportedItems = new List<Metric>();
@@ -168,7 +168,7 @@ public void ViewToRenameMetricConditionally()
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.InvalidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.InvalidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void ViewWithInvalidNameIgnoredConditionally(string viewNewName)
         {
             using var meter1 = new Meter("ViewToRenameMetricConditionallyTest");
@@ -205,7 +205,7 @@ public void ViewWithInvalidNameIgnoredConditionally(string viewNewName)
         }
 
         [Theory]
-        [MemberData(nameof(MetricsTestData.ValidInstrumentNames), MemberType = typeof(MetricsTestData))]
+        [MemberData(nameof(MetricTestData.ValidInstrumentNames), MemberType = typeof(MetricTestData))]
         public void ViewWithValidNameConditionally(string viewNewName)
         {
             using var meter1 = new Meter("ViewToRenameMetricConditionallyTest");