Fixed issue with manim init scene SCENE_NAME filename.py and removed necessity of main.py to be present in working directory (#2870)

* Fixed .py issue with manim init scene SCENE_NAME filename.py and removed necessity of main.py file to be present.

* fixed a problem when passing file name

* added interface test

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

Co-authored-by: Benjamin Hackl <[email protected]>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: 3 people

manim/cli/init/commands.py

@@ -149,9 +149,6 @@ def scene(**args):
 
     FILE is the name of file in which the SCENE will be inserted.
     """
-    if not Path("main.py").exists():
-        raise FileNotFoundError(f"{Path('main.py')} : Not a valid project directory.")
-
     template_name = click.prompt(
         "template",
         type=click.Choice(get_template_names(), False),
@@ -163,8 +160,12 @@ def scene(**args):
         scene = scene.replace(template_name + "Template", args["scene_name"], 1)
 
     if args["file_name"]:
-        file_name = Path(args["file_name"] + ".py")
+        if args["file_name"][-3:] == ".py":
+            file_name = args["file_name"]
+        else:
+            file_name = args["file_name"] + ".py"
 
+        file_name = Path(file_name)
         if file_name.is_file():
             # file exists so we are going to append new scene to that file
             with open(file_name, "a") as f:

tests/interface/test_commands.py

@@ -93,6 +93,28 @@ def test_manim_init_project(tmp_path):
         assert (Path(tmp_dir) / "testproject/manim.cfg").exists()
 
 
+def test_manim_init_scene(tmp_path):
+    command_named = ["init", "scene", "NamedFileTestScene", "my_awesome_file.py"]
+    command_unnamed = ["init", "scene", "DefaultFileTestScene"]
+    runner = CliRunner()
+    with runner.isolated_filesystem(temp_dir=tmp_path) as tmp_dir:
+        result = runner.invoke(
+            main, command_named, prog_name="manim", input="Default\n"
+        )
+        assert not result.exception
+        assert (Path(tmp_dir) / "my_awesome_file.py").exists()
+        with open(Path(tmp_dir) / "my_awesome_file.py") as f:
+            file_content = f.read()
+            assert "NamedFileTestScene(Scene):" in file_content
+        result = runner.invoke(
+            main, command_unnamed, prog_name="manim", input="Default\n"
+        )
+        assert (Path(tmp_dir) / "main.py").exists()
+        with open(Path(tmp_dir) / "main.py") as f:
+            file_content = f.read()
+            assert "DefaultFileTestScene(Scene):" in file_content
+
+
 def test_manim_new_command():
     command = ["new"]
     runner = CliRunner()