fix: Trim relative path indicators from Dockerfile path (#1203)

Author: HofmeisterAn

src/Testcontainers/Builders/ImageFromDockerfileBuilder.cs

@@ -3,6 +3,7 @@ namespace DotNet.Testcontainers.Builders
   using System;
   using System.Collections.Generic;
   using System.IO;
+  using System.Text.RegularExpressions;
   using Docker.DotNet.Models;
   using DotNet.Testcontainers.Configurations;
   using DotNet.Testcontainers.Images;
@@ -65,7 +66,8 @@ public ImageFromDockerfileBuilder WithName(IImage name)
     /// <inheritdoc />
     public ImageFromDockerfileBuilder WithDockerfile(string dockerfile)
     {
-      return Merge(DockerResourceConfiguration, new ImageFromDockerfileConfiguration(dockerfile: dockerfile));
+      var dockerfileFilePath = Regex.Replace(dockerfile, "^\\.(\\/|\\\\)", string.Empty, RegexOptions.None, TimeSpan.FromSeconds(1));
+      return Merge(DockerResourceConfiguration, new ImageFromDockerfileConfiguration(dockerfile: dockerfileFilePath));
     }
 
     /// <inheritdoc />

tests/Testcontainers.Tests/Unit/Images/ImageFromDockerfileTest.cs

@@ -100,8 +100,11 @@ public async Task ThrowsDockerfileDirectoryDoesNotExist()
       Assert.Equal($"Directory '{Path.GetFullPath(dockerfileDirectory)}' does not exist.", exception.Message);
     }
 
-    [Fact]
-    public async Task BuildsDockerImage()
+    [Theory]
+    [InlineData("Dockerfile")]
+    [InlineData("./Dockerfile")]
+    [InlineData(".\\Dockerfile")]
+    public async Task BuildsDockerImage(string dockerfile)
     {
       // Given
       IImage tag1 = new DockerImage("localhost/testcontainers", Guid.NewGuid().ToString("D"), string.Empty);
@@ -110,7 +113,7 @@ public async Task BuildsDockerImage()
 
       var imageFromDockerfileBuilder = new ImageFromDockerfileBuilder()
         .WithName(tag1)
-        .WithDockerfile("Dockerfile")
+        .WithDockerfile(dockerfile)
         .WithDockerfileDirectory("Assets/")
         .WithDeleteIfExists(true)
         .WithCreateParameterModifier(parameterModifier => parameterModifier.Tags.Add(tag2.FullName))