test: add & improve unit tests

src/ApplicationBuilderExtensions.cs

@@ -22,6 +22,9 @@ public static IApplicationBuilder UsePrometheusRequestDurations(this IApplicatio
     /// <param name="setupOptions">Setup Options</param>
     public static IApplicationBuilder UsePrometheusRequestDurations(this IApplicationBuilder app, Action<HttpRequestDurationsOptions> setupOptions)
     {
+        if (app == null)
+            throw new ArgumentNullException(nameof(app));
+
         var options = new HttpRequestDurationsOptions();
         setupOptions?.Invoke(options);
 

src/Defaults.cs

@@ -0,0 +1,15 @@
+namespace Prometheus.Client.HttpRequestDurations;
+
+internal static class Defaults
+{
+    internal const string MetricName = "http_request_duration_seconds";
+
+    internal static class LabelNames
+    {
+        internal const string StatusCode = "status_code";
+        internal const string Method = "method";
+        internal const string Controller = "controller";
+        internal const string Action = "action";
+        internal const string Path = "path";
+    }
+}

src/HttpRequestDurationsMiddleware.cs

@@ -28,19 +28,19 @@ public HttpRequestDurationsMiddleware(RequestDelegate next, HttpRequestDurations
         var labels = new List<string>();
 
         if (_options.IncludeStatusCode)
-            labels.Add("status_code");
+            labels.Add(Defaults.LabelNames.StatusCode);
 
         if (_options.IncludeMethod)
-            labels.Add("method");
+            labels.Add(Defaults.LabelNames.Method);
 
         if (_options.IncludeController)
-            labels.Add("controller");
+            labels.Add(Defaults.LabelNames.Controller);
 
         if (_options.IncludeAction)
-            labels.Add("action");
+            labels.Add(Defaults.LabelNames.Action);
 
         if (_options.IncludePath)
-            labels.Add("path");
+            labels.Add(Defaults.LabelNames.Path);
 
         if (_options.IncludeCustomLabels)
             labels.AddRange(_options.CustomLabels.Select(customLabel => customLabel.Key));

src/HttpRequestDurationsOptions.cs

@@ -7,7 +7,7 @@
 namespace Prometheus.Client.HttpRequestDurations;
 
 /// <summary>
-///     Options for RequestDurationsMiddleware
+///     Options for HttpRequestDurationsMiddleware
 /// </summary>
 public class HttpRequestDurationsOptions
 {
@@ -108,10 +108,7 @@ public class HttpRequestDurationsOptions
     /// </summary>
     public HttpRequestDurationsOptions()
     {
-        MetricName = "http_request_duration_seconds";
-
+        MetricName = Defaults.MetricName;
         IncludeStatusCode = true;
-        IncludeMethod = false;
-        IncludePath = false;
     }
 }

src/Prometheus.Client.HttpRequestDurations.csproj

@@ -1,6 +1,6 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <Description>Metrics logging of request durations for the Prometheus.Client</Description>
+    <Description>HTTP request durations for the Prometheus.Client</Description>
     <TargetFramework>net6.0</TargetFramework>
     <RepositoryUrl>https://github.com/prom-client-net/prom-client-httprequestdurations</RepositoryUrl>
   </PropertyGroup>

tests/ApplicationBuilderExtensionsTests.cs

@@ -0,0 +1,70 @@
+using System;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.AspNetCore.Http;
+using Microsoft.Extensions.DependencyInjection;
+using Prometheus.Client.Collectors;
+using Xunit;
+
+namespace Prometheus.Client.HttpRequestDurations.Tests;
+
+public class ApplicationBuilderExtensionsTests
+{
+    private readonly ServiceCollection _services = new();
+
+    [Fact]
+    public void AppBuilderIsNull_Throws_ArgumentNullException()
+    {
+        Assert.Throws<ArgumentNullException>(() => ((ApplicationBuilder)null).UsePrometheusRequestDurations());
+    }
+
+    [Fact]
+    public void TargetIsType_HttpRequestDurationsMiddleware()
+    {
+        var app = new ApplicationBuilder(_services.BuildServiceProvider());
+        _services.AddSingleton<ICollectorRegistry, CollectorRegistry>();
+        app.UsePrometheusRequestDurations();
+
+        Assert.IsType<HttpRequestDurationsMiddleware>(app.Build().Target);
+    }
+
+    [Fact]
+    public void With_DefaultCollectorRegistry()
+    {
+        var app = new ApplicationBuilder(_services.BuildServiceProvider());
+        app.UsePrometheusRequestDurations();
+        app.Build();
+
+        Assert.True(Metrics.DefaultCollectorRegistry.TryGet(Defaults.MetricName, out var defaultCollector));
+
+        // Cleanup
+        Metrics.DefaultCollectorRegistry?.Remove(defaultCollector);
+    }
+
+    [Fact]
+    public void With_DICollecorRegistry()
+    {
+        var registry = new CollectorRegistry();
+        _services.AddSingleton<ICollectorRegistry>(registry);
+        var app = new ApplicationBuilder(_services.BuildServiceProvider());
+        app.UsePrometheusRequestDurations();
+        app.Build();
+
+        Assert.True(registry.TryGet(Defaults.MetricName, out _));
+
+        Assert.False(Metrics.DefaultCollectorRegistry.TryGet(Defaults.MetricName, out _));
+    }
+
+    [Fact]
+    public void With_CustomCollecorRegistry()
+    {
+        var registry = new CollectorRegistry();
+
+        var app = new ApplicationBuilder(_services.BuildServiceProvider());
+        app.UsePrometheusRequestDurations(q => q.CollectorRegistry = registry);
+        app.Build();
+
+        Assert.True(registry.TryGet(Defaults.MetricName, out _));
+
+        Assert.False(Metrics.DefaultCollectorRegistry.TryGet(Defaults.MetricName, out _));
+    }
+}

tests/HttpContextExtensionsTests.cs

@@ -0,0 +1,26 @@
+using System;
+using Microsoft.AspNetCore.Http;
+using Xunit;
+
+namespace Prometheus.Client.HttpRequestDurations.Tests;
+
+public class HttpContextExtensionsTests
+{
+    [Fact]
+    public void GetRouteName_When_HttpContextIsNull_Throws_ArgumentNullException()
+    {
+        Assert.Throws<ArgumentNullException>(() => ((HttpContext)null).GetRouteName());
+    }
+
+    [Fact]
+    public void GetControllerName_When_HttpContextIsNull_Throws_ArgumentNullException()
+    {
+        Assert.Throws<ArgumentNullException>(() => ((HttpContext)null).GetControllerName());
+    }
+
+    [Fact]
+    public void GetActionName_When_HttpContextIsNull_Throws_ArgumentNullException()
+    {
+        Assert.Throws<ArgumentNullException>(() => ((HttpContext)null).GetActionName());
+    }
+}

tests/HttpRequestDurationsMiddlewareTests.cs

@@ -0,0 +1,196 @@
+using System;
+using System.Collections.Generic;
+using Microsoft.AspNetCore.Builder;
+using Microsoft.Extensions.DependencyInjection;
+using Prometheus.Client.Collectors;
+using Xunit;
+
+namespace Prometheus.Client.HttpRequestDurations.Tests;
+
+public class HttpRequestDurationsMiddlewareTests
+{
+    private readonly ICollectorRegistry _registry;
+    private readonly IApplicationBuilder _app;
+
+    public HttpRequestDurationsMiddlewareTests()
+    {
+        _registry = new CollectorRegistry();
+
+        var services = new ServiceCollection();
+        services.AddSingleton(_registry);
+        _app = new ApplicationBuilder(services.BuildServiceProvider());
+    }
+
+    [Fact]
+    public void Use_DefaultCollectorNotNull()
+    {
+        UseBuildApp();
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+
+        Assert.NotNull(collector);
+    }
+
+    [Theory]
+    [InlineData("custom_name")]
+    [InlineData("http_seconds")]
+    [InlineData("myapp_http_request_duration_seconds")]
+    public void Use_WithCustomMetricName_CustomCollectorNotNull(string metricName)
+    {
+        UseBuildApp(q => q.MetricName = metricName);
+
+        _registry.TryGet(metricName, out var collector);
+
+        Assert.NotNull(collector);
+    }
+
+    [Fact]
+    public void Use_WithCustomMetricName_DefaultCollectorIsNull()
+    {
+        UseBuildApp(q => q.MetricName = "custom_name");
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+
+        Assert.Null(collector);
+    }
+
+    [Fact]
+    public void Collector_IsHistogram()
+    {
+        UseBuildApp();
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        Assert.IsAssignableFrom<IMetricFamily<IHistogram>>(collector);
+    }
+
+    [Fact]
+    public void Metric_ContainsStatusCodeLabel()
+    {
+        UseBuildApp(q => q.IncludeStatusCode = true);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains(Defaults.LabelNames.StatusCode, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainStatusCodeLabel()
+    {
+        UseBuildApp(q => q.IncludeStatusCode = false);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain(Defaults.LabelNames.StatusCode, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_ContainsMethodLabel()
+    {
+        UseBuildApp(q => q.IncludeMethod = true);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains(Defaults.LabelNames.Method, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainMethodLabel()
+    {
+        UseBuildApp(q => q.IncludeMethod = false);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain(Defaults.LabelNames.Method, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_ContainsControllerLabel()
+    {
+        UseBuildApp(q => q.IncludeController = true);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains(Defaults.LabelNames.Controller, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainControllerLabel()
+    {
+        UseBuildApp(q => q.IncludeController = false);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain(Defaults.LabelNames.Controller, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_ContainsActionLabel()
+    {
+        UseBuildApp(q => q.IncludeAction = true);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains(Defaults.LabelNames.Action, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainActionLabel()
+    {
+        UseBuildApp(q => q.IncludeAction = false);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain(Defaults.LabelNames.Action, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_ContainsPathLabel()
+    {
+        UseBuildApp(q => q.IncludePath = true);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains(Defaults.LabelNames.Path, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainPathLabel()
+    {
+        UseBuildApp(q => q.IncludePath = false);
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain(Defaults.LabelNames.Path, metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_ContainsCustomLabel()
+    {
+        UseBuildApp(q => q.CustomLabels = new Dictionary<string, Func<string>>
+        {
+            {
+                "custom_label", () => "custom_value"
+            }
+        });
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.Contains("custom_label", metric.LabelNames);
+        Assert.DoesNotContain("custom_value", metric.LabelNames);
+    }
+
+    [Fact]
+    public void Metric_DoesNotContainCustomLabel()
+    {
+        UseBuildApp();
+
+        _registry.TryGet(Defaults.MetricName, out var collector);
+        var metric = (IMetricFamily<IHistogram>)collector;
+        Assert.DoesNotContain("custom_label", metric.LabelNames);
+    }
+
+    private void UseBuildApp(Action<HttpRequestDurationsOptions> setupOptions = null)
+    {
+        _app.UsePrometheusRequestDurations(setupOptions).Build();
+    }
+}