This way of adding configuration do not work

[akshay-zz]

var builder = new TestcontainersBuilder<TestcontainersContainer>();
builder.WithImage("someimage");
builder.WithName("someContainerName");

var container = builder.Build();

It does not configure the container. Is this planned or something else is the problem?

Although the following works the way it should

var container = new TestcontainersBuilder<TestcontainersContainer>()
        .WithImage("someImage")
        .WithName("containerName")
        .Build();

[HofmeisterAn]

It does not configure the container. Is this planned or something else is the problem?

This is on purpose. The data held inside the builder is immutable. Each build method call returns a new instance. This allows to share configurations for e.g. for A/B testing, like:

var baseBuilder = new PostgreSqlBuilder()
  .WithUsername("Username")
  .WithPassword("Password")
  .WithLabel("Key", "Value");

var postgres15 = baseBuilder
  .WithImage("postgres:15")
  .Build();

var postgres14 = baseBuilder
  .WithImage("postgres:14")
  .Build();

You can change your example to:

var builder = new TestcontainersBuilder<TestcontainersContainer>();
builder = builder.WithImage("someimage");
builder = builder.WithName("someContainerName");
var container = builder.Build();