correct behavior for case-insensitive platforms

Author: Josh Huber

src/GitVersionCore.Tests/NamedConfigFileLocatorTests.cs

@@ -52,6 +52,16 @@ public void DoNotThrowWhenWorkingAndRepoPathsAreSame()
             Should.NotThrow(() => { configFileLocator.Verify(workingPath, repoPath, fileSystem); });
         }
 
+        [Test]
+        [Platform(Exclude = "Linux,Unix")]
+        public void DoNotThrowWhenWorkingAndRepoPathsAreSame_WithDifferentCasing()
+        {
+            workingPath = DefaultRepoPath.ToLower();
+            SetupConfigFileContent(string.Empty, path: workingPath);
+
+            Should.NotThrow(() => { configFileLocator.Verify(workingPath, repoPath, fileSystem); });
+        }
+
         [Test]
         public void DoNotThrowWhenConfigFileIsInSubDirectoryOfRepoPath()
         {

src/GitVersionCore.Tests/TestFileSystem.cs

@@ -9,7 +9,8 @@ namespace GitVersionCore.Tests
 {
     public class TestFileSystem : IFileSystem
     {
-        Dictionary<string, byte[]> fileSystem = new Dictionary<string, byte[]>(StringComparer.OrdinalIgnoreCase);
+        private static IEqualityComparer<string> fileSystemCasingComparer = System.Environment.OSVersion.Platform == PlatformID.Unix ? StringComparer.Ordinal : StringComparer.OrdinalIgnoreCase;
+        Dictionary<string, byte[]> fileSystem = new Dictionary<string, byte[]>(fileSystemCasingComparer);
 
         public void Copy(string @from, string to, bool overwrite)
         {

src/GitVersionCore/Configuration/NamedConfigFileLocator.cs

@@ -35,7 +35,8 @@ private void WarnAboutAmbiguousConfigFileSelection(string workingDirectory, stri
             var workingConfigFile = GetConfigFilePath(workingDirectory, fileSystem);
             var projectRootConfigFile = GetConfigFilePath(projectRootDirectory, fileSystem);
 
-            if (Path.GetFullPath(workingConfigFile).Equals(Path.GetFullPath(projectRootConfigFile)))
+            var fileSystemCasingComparer = System.Environment.OSVersion.Platform == PlatformID.Unix ? StringComparison.Ordinal : StringComparison.OrdinalIgnoreCase;
+            if (Path.GetFullPath(workingConfigFile).Equals(Path.GetFullPath(projectRootConfigFile), fileSystemCasingComparer))
                 return;
 
             var hasConfigInWorkingDirectory = fileSystem.Exists(workingConfigFile);