Use dockerignore with the same name as the dockerfile if it exists

Author: ifan-t

src/Testcontainers/Images/DockerIgnoreFile.cs

@@ -15,33 +15,37 @@ internal sealed class DockerIgnoreFile : IgnoreFile
     /// Initializes a new instance of the <see cref="DockerIgnoreFile" /> class.
     /// </summary>
     /// <param name="dockerignoreFileDirectory">Directory that contains all docker configuration files.</param>
-    /// <param name="dockerignoreFile">.dockerignore file name.</param>
+    /// <param name="dockerignoreFileExtension">.dockerignore file extension.</param>
     /// <param name="dockerfileFile">Dockerfile file name.</param>
     /// <param name="logger">The logger.</param>
-    public DockerIgnoreFile(string dockerignoreFileDirectory, string dockerignoreFile, string dockerfileFile, ILogger logger)
-      : this(new DirectoryInfo(dockerignoreFileDirectory), dockerignoreFile, dockerfileFile, logger)
+    public DockerIgnoreFile(string dockerignoreFileDirectory, string dockerignoreFileExtension, string dockerfileFile, ILogger logger)
+      : this(new DirectoryInfo(dockerignoreFileDirectory), dockerignoreFileExtension, dockerfileFile, logger)
     {
     }
 
     /// <summary>
     /// Initializes a new instance of the <see cref="DockerIgnoreFile" /> class.
     /// </summary>
     /// <param name="dockerignoreFileDirectory">Directory that contains all docker configuration files.</param>
-    /// <param name="dockerignoreFile">.dockerignore file name.</param>
+    /// <param name="dockerignoreFileExtension">.dockerignore file extension.</param>
     /// <param name="dockerfileFile">Dockerfile file name.</param>
     /// <param name="logger">The logger.</param>
-    public DockerIgnoreFile(FileSystemInfo dockerignoreFileDirectory, string dockerignoreFile, string dockerfileFile, ILogger logger)
-      : base(GetPatterns(dockerignoreFileDirectory, dockerignoreFile, dockerfileFile), logger)
+    public DockerIgnoreFile(FileSystemInfo dockerignoreFileDirectory, string dockerignoreFileExtension, string dockerfileFile, ILogger logger)
+      : base(GetPatterns(dockerignoreFileDirectory, dockerignoreFileExtension, dockerfileFile), logger)
     {
     }
 
-    private static IEnumerable<string> GetPatterns(FileSystemInfo dockerignoreFileDirectory, string dockerignoreFile, string dockerfileFile)
+    private static IEnumerable<string> GetPatterns(FileSystemInfo dockerignoreFileDirectory, string dockerignoreFileExtension, string dockerfileFile)
     {
-      var dockerignoreFilePath = Path.Combine(dockerignoreFileDirectory.FullName, dockerignoreFile);
+      var customDockerIgnoreFilePath = Path.Combine(dockerignoreFileDirectory.FullName, dockerfileFile + dockerignoreFileExtension);
+
+      var dockerignoreFilePath = File.Exists(customDockerIgnoreFilePath)
+        ? customDockerIgnoreFilePath
+        : Path.Combine(dockerignoreFileDirectory.FullName, dockerignoreFileExtension);
 
       // These files are necessary and sent to the Docker daemon. The ADD and COPY instructions do not copy them to the image:
       // https://docs.docker.com/engine/reference/builder/#dockerignore-file.
-      var negateNecessaryFiles = new[] { dockerignoreFile, dockerfileFile }
+      var negateNecessaryFiles = new[] { dockerignoreFileExtension, dockerfileFile }
         .Select(file => "!" + file);
 
       var dockerignorePatterns = File.Exists(dockerignoreFilePath)