fromDockerfile treats dockerFileName argument as folder

[ViggoV]

Expected Behaviour
Given the following

const container = await GenericContainer.fromDockerfile('.', 'build/next.Dockerfile').build()

I expect the output to be roughly equivalent to docker build -f build/next.Dockerfile ., ie. build from the next.Dockerfile file located in the build/ folder with the docker context "."

Actual Behaviour

The command fails because the second argument is considered a folder and /Dockerfile is appended. This ultimately results in the error:

Error: ENOTDIR: not a directory, open '/path/to/project/build/next.Dockerfile/Dockerfile'

Testcontainer Logs
...

Steps to Reproduce

1. In this environment...

• Any project with custom named Dockerfiles in a subfolder in relation to the context

2. With this config...

• Any

3. Run '...'

• const container = await GenericContainer.fromDockerfile('.', 'build/next.Dockerfile').build()

4. See error...

• Error: ENOTDIR: not a directory, open '/path/to/project/build/next.Dockerfile/Dockerfile'
  

Environment Information

• Operating System: MacOS 15.5
• Docker Version: 28.1.1, build 4eba377
• Node version: v24.0.1
• Testcontainers version: 11.0.0

[ViggoV]

Turns out this was a problem with VSCode/Playwright caching