Accept explicit output file path

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "mobuild"
-version = "0.2.0"
-description = "Add your description here"
+version = "0.3.0"
+description = "A minimal build tool to turn marimo notebooks into Python packages."
 readme = "README.md"
 authors = [
     { name = "koaning", email = "vincentwarmerdam@gmail.com" }

src/mobuild/__init__.py

@@ -31,7 +31,7 @@ def _collect_top_level_names(code: str) -> list[str]:
     return names
 
 
-def _write_file(file: Path, out_folder: Path):
+def _write_file(file: Path, out_path: Path):
     """Extract exported code from a single marimo notebook and write it as a plain Python file.
 
     Marimo notebooks are valid Python files. Each notebook defines a global ``app``
@@ -45,7 +45,7 @@ def _write_file(file: Path, out_folder: Path):
          execution order.
       3. Selects only cells whose source code contains the ``## EXPORT`` marker.
       4. Concatenates those cells in execution order (respecting the DAG) and
-         writes the result to ``out_folder/<notebook_filename>``.
+         writes the result to ``out_path``.
       5. Prepends an ``__all__`` so the generated module only exposes the
          public names that were explicitly exported.
 
@@ -93,19 +93,22 @@ def _write_file(file: Path, out_folder: Path):
     if names:
         code_export = "__all__ = " + repr(names) + "\n\n" + code_export
 
-    (out_folder / file.name).write_text(code_export)
+    out_path.parent.mkdir(parents=True, exist_ok=True)
+    out_path.write_text(code_export)
 
 
 @app.command(no_args_is_help=True)
-def export(input_file: Path, output_folder: Path):
+def export(input_file: Path, output_path: Path):
     """Build a Python file from a single Marimo notebook."""
     input_file = Path(input_file)
-    output_folder = Path(output_folder)
+    output_path = Path(output_path)
     if not input_file.exists():
         typer.echo(f"Input file {input_file} does not exist")
         raise typer.Exit(1)
-    output_folder.mkdir(parents=True, exist_ok=True)
-    _write_file(input_file, output_folder)
+    if output_path.is_dir():
+        typer.echo(f"Output path {output_path} is a directory, please provide a file path")
+        raise typer.Exit(1)
+    _write_file(input_file, output_path)
 
 
 @app.command(no_args_is_help=True)
@@ -124,6 +127,6 @@ def init(name: str, output_folder: Path = Path(".")):
     )
 
 
-def runtime_sync(output_folder: Path):
-    """Write the current marimo notebook to the output folder as a normal Python file."""
-    _write_file(__file__, output_folder)
+def runtime_sync(output_path: Path):
+    """Write the current marimo notebook to the given output path as a normal Python file."""
+    _write_file(Path(__file__), output_path)

src/mobuild/static/cookiecutter/{{cookiecutter.project_name}}/Makefile

@@ -12,4 +12,4 @@ clean:
 	rm -rf .pytest_cache/
 
 build:
-	uv run mobuild export nbs/__init__.py src
+	uv run mobuild export nbs/__init__.py src/__init__.py

tests/test_basics.py

@@ -1,24 +1,33 @@
+import click
+import pytest
 from mobuild import export, init
 
 
 def test_basics(tmp_path):
-    out_dir = tmp_path / "proj1_out"
-    out_dir.mkdir()
-    export(input_file="tests/proj1/__init__.py", output_folder=out_dir)
-    out = (out_dir / "__init__.py").read_text()
+    out_file = tmp_path / "proj1_out" / "__init__.py"
+    export(input_file="tests/proj1/__init__.py", output_path=out_file)
+    out = out_file.read_text()
     assert "a = 1" in out
     assert "b = 2" not in out
     assert "## export" not in out.lower()  # Marker should be stripped
     assert '__all__' in out
     assert "'a'" in out
 
 
+def test_custom_output_name(tmp_path):
+    """The user can pick any file name for the output."""
+    out_file = tmp_path / "my_module.py"
+    export(input_file="tests/proj1/__init__.py", output_path=out_file)
+    out = out_file.read_text()
+    assert "a = 1" in out
+    assert '__all__' in out
+
+
 def test_selective_export(tmp_path):
     """Only cells marked with ## EXPORT should appear in the output."""
-    out_dir = tmp_path / "proj2_out"
-    out_dir.mkdir()
-    export(input_file="tests/proj2/__init__.py", output_folder=out_dir)
-    out = (out_dir / "__init__.py").read_text()
+    out_file = tmp_path / "proj2_out" / "__init__.py"
+    export(input_file="tests/proj2/__init__.py", output_path=out_file)
+    out = out_file.read_text()
 
     # Exported definitions should be present
     assert "def greet" in out
@@ -42,6 +51,14 @@ def test_selective_export(tmp_path):
 
 
 
+def test_folder_is_not_sufficient(tmp_path):
+    """Passing a directory instead of a file path should fail."""
+    out_dir = tmp_path / "some_folder"
+    out_dir.mkdir()
+    with pytest.raises(click.exceptions.Exit):
+        export(input_file="tests/proj1/__init__.py", output_path=out_dir)
+
+
 def test_init(tmp_path):
     out_dir = tmp_path / "output"
     init(name="output", output_folder=tmp_path)