fix: consider any Python file (thanks @tolusonaike)

Fixes #138

Signed-off-by: Augusto W. Andreoli <andreoliwa@gmail.com>

README.md

@@ -50,10 +50,15 @@ This style will assert that:
 
 ## Quick setup
 
-To try the package, simply install it (in a virtualenv or globally, wherever) and run `flake8`:
+To try the package, simply install it (in a virtualenv or globally) and run `flake8` on a project with at least one Python (`.py`) file:
 
+    # Install using pip:
     $ pip install -U nitpick
-    $ flake8
+
+    # Or using Poetry:
+    $ poetry add --dev nitpick
+
+    $ flake8 .
 
 Nitpick will download and use the opinionated [default style file](https://raw.githubusercontent.com/andreoliwa/nitpick/v0.21.4/nitpick-style.toml).
 

docs/installation_guide.rst

@@ -8,12 +8,19 @@ Installation guide
 Quick setup
 -----------
 
-To try the package, simply install it (in a virtualenv or globally, wherever) and run ``flake8``:
+To try the package, simply install it (in a virtualenv or globally) and run flake8_ on a project with at least one Python (``.py``) file:
 
 .. code-block:: shell
 
+    $ cd /path/to/my/python/project
+
+    # Install using pip:
     $ pip install -U nitpick
-    $ flake8
+
+    # Or using Poetry:
+    $ poetry add --dev nitpick
+
+    $ flake8 .
 
 Nitpick_ will download and use the opinionated `default style file`_.
 

src/nitpick/app.py

@@ -130,11 +130,16 @@ def find_main_python_file(self) -> Path:
         The search order is:
         1. Python files that belong to the root dir of the project (e.g.: ``setup.py``, ``autoapp.py``).
         2. ``manage.py``: they can be on the root or on a subdir (Django projects).
-        3. Any other ``*.py`` Python file.
+        3. Any other ``*.py`` Python file on the root dir and subdir.
+           This avoid long recursions when there is a ``node_modules`` subdir for instance.
         """
         for the_file in itertools.chain(
+            # 1.
             [self.root_dir / root_file for root_file in ROOT_PYTHON_FILES],
+            # 2.
             self.root_dir.glob("*/{}".format(MANAGE_PY)),
+            # 3.
+            self.root_dir.glob("*.py"),
             self.root_dir.glob("*/*.py"),
         ):
             if the_file.exists():

src/nitpick/exceptions.py

@@ -34,10 +34,10 @@ class NoRootDir(PluginError):
 
 
 class NoPythonFile(PluginError):
-    """No Python file under the root dir."""
+    """No Python file was found."""
 
     number = 2
-    message = "No Python file was found under the root dir {!r}"
+    message = "No Python file was found on the root dir and subdir of {!r}"
 
     def __init__(self, root_dir: Path, *args: object) -> None:
         self.message = self.message.format(str(root_dir))

tests/test_config.py

@@ -1,4 +1,6 @@
 """Config tests."""
+import pytest
+
 from tests.helpers import ProjectMock
 
 
@@ -16,10 +18,42 @@ def test_multiple_root_dirs(request):
     ).style("").flake8().assert_no_errors()
 
 
-def test_no_main_python_file_root_dir(request):
-    """No main Python file on the root dir."""
+def test_no_python_file_root_dir(request):
+    """No Python file on the root dir."""
     project = ProjectMock(request, setup_py=False).pyproject_toml("").save_file("whatever.sh", "", lint=True).flake8()
-    project.assert_single_error("NIP102 No Python file was found under the root dir {!r}".format(str(project.root_dir)))
+    project.assert_single_error(
+        "NIP102 No Python file was found on the root dir and subdir of {!r}".format(str(project.root_dir))
+    )
+
+
+@pytest.mark.parametrize(
+    "python_file,error", [("depth1.py", False), ("subdir/depth2.py", False), ("subdir/another/depth3.py", True)]
+)
+def test_at_least_one_python_file(python_file, error, request):
+    """At least one Python file on the root dir, even if it's not a main file."""
+    project = (
+        ProjectMock(request, setup_py=False)
+        .style(
+            """
+            ["pyproject.toml".tool.black]
+            lines = 100
+            """
+        )
+        .pyproject_toml(
+            """
+            [tool.black]
+            lines = 100
+            """
+        )
+        .save_file(python_file, "", lint=True)
+        .flake8()
+    )
+    if error:
+        project.assert_single_error(
+            "NIP102 No Python file was found on the root dir and subdir of {!r}".format(str(project.root_dir))
+        )
+    else:
+        project.assert_no_errors()
 
 
 def test_django_project_structure(request):