Refactor and unit test for ToSnakeCase extension method (#42)

* Refactor and unit test for ToSnakeCase extension method

* Code cleanup

* Lock contention assertion should be GreaterThanOrEqualTo instead of EqualTo

src/prometheus-net.DotNetRuntime.Tests/StatsCollectors/IntegrationTests/ContentionStatsCollectorTests.cs

@@ -63,7 +63,7 @@ public async Task Will_measure_contention_on_a_contested_lock()
 
             // Why -1? The first thread will not contend the lock 
             const int numLocksContended = numThreads - 1;
-            Assert.That(() => StatsCollector.ContentionTotal.Value, Is.EqualTo(numLocksContended).After(200, 10));
+            Assert.That(() => StatsCollector.ContentionTotal.Value, Is.GreaterThanOrEqualTo(numLocksContended).After(200, 10));
 
             // Pattern of expected contention times is: 50ms, 100ms, 150ms, etc.
             var expectedDelay = TimeSpan.FromMilliseconds(Enumerable.Range(1, numLocksContended).Aggregate(sleepForMs, (acc, next) => acc + (sleepForMs * next)));

src/prometheus-net.DotNetRuntime.Tests/StatsCollectors/IntegrationTests/ExceptionStatsCollectorTests.cs

@@ -1,9 +1,6 @@
 using NUnit.Framework;
 using Prometheus.DotNetRuntime.StatsCollectors;
 using System;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
 
 namespace Prometheus.DotNetRuntime.Tests.StatsCollectors.IntegrationTests
 {
@@ -23,9 +20,9 @@ public void Will_measure_when_occurring_an_exception()
 
             try
             {
-                var result = 1 / divider;
+                _ = 1 / divider;
             }
-            catch (System.DivideByZeroException divZeroEx)
+            catch (DivideByZeroException)
             {
             }
 

src/prometheus-net.DotNetRuntime.Tests/StatsCollectors/Util/StringExtensionsTests.cs

@@ -0,0 +1,17 @@
+using NUnit.Framework;
+using Prometheus.DotNetRuntime.StatsCollectors.Util;
+
+namespace Prometheus.DotNetRuntime.Tests.StatsCollectors.Util
+{
+    public class StringExtensionsTests
+    {
+        [TestCase("", "")]
+        [TestCase("myGreatVariableName", "my_great_variable_name")]
+        [TestCase("my_great_variable_name", "my_great_variable_name")]
+        [TestCase("MyGreatVariableName", "my_great_variable_name")]
+        public void ToSnakeCase_Should_Convert_To_Snake_Case(string given, string expected)
+        {
+            Assert.AreEqual(given.ToSnakeCase(), expected);
+        }
+    }
+}

src/prometheus-net.DotNetRuntime/StatsCollectors/Util/Cache.cs

@@ -100,12 +100,11 @@ private void CleanupExpiredValues()
 
             foreach (var key in _cache.Keys.ToArray())
             {
-                CacheValue<TValue> value;
-                if (!_cache.TryGetValue(key, out value))
+                if (!_cache.TryGetValue(key, out var value))
                     continue;
 
                 if (value.TimeStamp < earliestAddedTime)
-                    _cache.TryRemove(key, out var _);
+                    _cache.TryRemove(key, out _);
             }
         }
     }

src/prometheus-net.DotNetRuntime/StatsCollectors/Util/EventPairTimer.cs

@@ -1,6 +1,5 @@
 using System;
 using System.Diagnostics.Tracing;
-using System.Runtime.CompilerServices;
 
 namespace Prometheus.DotNetRuntime.StatsCollectors.Util
 {

src/prometheus-net.DotNetRuntime/StatsCollectors/Util/LabelGenerator.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
-using System.Text;
 
 namespace Prometheus.DotNetRuntime.StatsCollectors.Util
 {
@@ -14,14 +13,8 @@ public class LabelGenerator
         public static Dictionary<TEnum, string> MapEnumToLabelValues<TEnum>()
             where TEnum : Enum
         {
-            var dict = new Dictionary<TEnum, string>();
-
-            foreach (var v in Enum.GetValues(typeof(TEnum)).Cast<TEnum>())
-            {
-                dict.Add(v, Enum.GetName(typeof(TEnum), v).ToSnakeCase());
-            }
-
-            return dict;
+            return Enum.GetValues(typeof(TEnum)).Cast<TEnum>()
+                .ToDictionary(k => k, v => Enum.GetName(typeof(TEnum), v).ToSnakeCase());
         }
     }
 }

src/prometheus-net.DotNetRuntime/StatsCollectors/Util/SamplingRate.cs

@@ -1,4 +1,3 @@
-using System;
 using System.Threading;
 
 namespace Prometheus.DotNetRuntime.StatsCollectors.Util

src/prometheus-net.DotNetRuntime/StatsCollectors/Util/StringExtensions.cs

@@ -7,28 +7,25 @@ public static class StringExtensions
         public static string ToSnakeCase(this string str)
         {
             var sb = new StringBuilder();
-            bool lastCharWasUpper = false;
-            bool isFirst = true;
+            var lastCharWasUpper = false;
 
-            foreach (var c in str)
+            for(var i = 0 ; i < str.Length ; i++)
             {
-                if (char.IsUpper(c))
+                if (char.IsUpper(str[i]))
                 {
-                    if (!lastCharWasUpper && !isFirst)
+                    if (!lastCharWasUpper && i != 0)
                     {
                         sb.Append("_");
                     }
 
-                    sb.Append(char.ToLower(c));
+                    sb.Append(char.ToLower(str[i]));
                     lastCharWasUpper = true;
                 }
                 else
                 {
-                    sb.Append(c);
+                    sb.Append(str[i]);
                     lastCharWasUpper = false;
                 }
-
-                isFirst = false;
             }
 
             return sb.ToString();