Test Data And Results

Isolated Workspaces

filesystem prepares mutable files under an isolated runtime directory:

test."reads configuration" = { terminal, filesystem }: [
  (filesystem.writeFile "config.toml" ''
    greeting = "Hello"
  '')
  (terminal.open "${application} --config ${filesystem.root}/config.toml")
  (expect (terminal.getByText "Hello")).toBeVisible
];

Paths are relative to the filesystem root. Absolute paths and parent traversal are rejected during Nix evaluation. Other actions include makeDirectory, copyFile, copyTree, symlink, setMode, and remove.

Saved Command Results

Run side-effecting commands once and save their output:

test."creates an item once" = { machine, result }: [
  (machine.configure { })
  (machine.run {
    command = "example create";
    saveAs = "create";
  })
  ((expect (result.command "create")).toHaveExitCode 0)
  ((expect (result.stdout "create")).toContainStdout "created")
];

Saved HTTP Results

Use http.send for mutating requests:

test."creates an item through HTTP" = { machine, http, result }: [
  (machine.configure { modules = [ apiModule ]; })
  (http.send machine {
    method = "POST";
    url = "http://localhost/items";
    body = ''{"name":"example"}'';
    saveAs = "create-item";
  })
  ((expect (result.command "create-item")).toHaveExitCode 0)
  ((expect (result.stdout "create-item")).toContainStdout "created")
];

Saved-result assertions never repeat the original side effect.