Run tests in parallel by default, and update CONTRIBUTING.md to recommend this flow.

test_mesher.py was reusing the same filename across tests which meant
that when running in parallel tests would stomp on each
other. Robustified by having each test use a distinct file name.

.github/workflows/test.yml

@@ -23,4 +23,4 @@ jobs:
           python-version: ${{ matrix.python-version }}
       - name: test
         run: |
-          python -m pytest
+          python -m pytest -n auto

CONTRIBUTING.md

@@ -3,10 +3,10 @@ tests, ensure they build and pass, and ensure that `pylint` and `mypy`
 are happy with your code.
 
 - Install `pip` following their [documentation](https://pip.pypa.io/en/stable/installation/).
-- Install development dependencies: `pip install pylint pytest mypy sphinx black`
-- Install docs dependencies: `pip install -r docs/requirements.txt` (might need to comment out the build123d line in that file)
+- Install development dependencies: `pip install -e .[development]`
+- Install docs dependencies: `pip install -e .[docs]`
 - Install `build123d` in editable mode from current dir:  `pip install -e .`
-- Run tests with: `python -m pytest`
+- Run tests with: `python -m pytest -n auto`
 - Build docs with: `cd docs && make html`
 - Check added files' style with: `pylint <path/to/file.py>` 
 - Check added files' type annotations with: `mypy <path/to/file.py>`

pyproject.toml

@@ -64,6 +64,7 @@ development = [
     "wheel",
     "pytest",
     "pytest-cov",
+    "pytest-xdist",
     "pylint",
     "mypy",
     "black",

tests/test_mesher.py

@@ -2,7 +2,8 @@ import unittest, uuid
 from packaging.specifiers import SpecifierSet
 from pathlib import Path
 from os import fsdecode, fsencode
-import time
+import sys
+import tempfile
 
 import pytest
 
@@ -18,6 +19,12 @@ from build123d.geometry import Axis, Color, Location, Vector, VectorLike
 from build123d.mesher import Mesher
 
 
+def temp_3mf_file():
+    caller = sys._getframe(1)
+    prefix = f"build123d_{caller.f_locals.get('self').__class__.__name__}_{caller.f_code.co_name}"
+    return tempfile.mktemp(suffix=".3mf", prefix=prefix)
+
+
 class DirectApiTestCase(unittest.TestCase):
     def assertTupleAlmostEquals(
         self,
@@ -47,11 +54,12 @@ class TestProperties(unittest.TestCase):
 
     def test_units(self):
         for unit in Unit:
+            filename = temp_3mf_file()
             exporter = Mesher(unit=unit)
             exporter.add_shape(Solid.make_box(1, 1, 1))
-            exporter.write("test.3mf")
+            exporter.write(filename)
             importer = Mesher()
-            _shape = importer.read("test.3mf")
+            _shape = importer.read(filename)
             self.assertEqual(unit, importer.model_unit)
 
     def test_vertex_and_triangle_counts(self):
@@ -73,9 +81,10 @@ class TestMetaData(unittest.TestCase):
         exporter.add_shape(Solid.make_box(1, 1, 1))
         exporter.add_meta_data("test_space", "test0", "some data", "str", True)
         exporter.add_meta_data("test_space", "test1", "more data", "str", True)
-        exporter.write("test.3mf")
+        filename = temp_3mf_file()
+        exporter.write(filename)
         importer = Mesher()
-        _shape = importer.read("test.3mf")
+        _shape = importer.read(filename)
         imported_meta_data: list[dict] = importer.get_meta_data()
         self.assertEqual(imported_meta_data[0]["name_space"], "test_space")
         self.assertEqual(imported_meta_data[0]["name"], "test0")
@@ -90,9 +99,10 @@ class TestMetaData(unittest.TestCase):
         exporter = Mesher()
         exporter.add_shape(Solid.make_box(1, 1, 1))
         exporter.add_code_to_metadata()
-        exporter.write("test.3mf")
+        filename = temp_3mf_file()
+        exporter.write(filename)
         importer = Mesher()
-        _shape = importer.read("test.3mf")
+        _shape = importer.read(filename)
         source_code = importer.get_meta_data_by_key("build123d", "test_mesher.py")
         self.assertEqual(len(source_code), 2)
         self.assertEqual(source_code["type"], "python")
@@ -118,9 +128,10 @@ class TestMeshProperties(unittest.TestCase):
                     part_number=str(mesh_type.value),
                     uuid_value=test_uuid,
                 )
-                exporter.write("test.3mf")
+                filename = temp_3mf_file()
+                exporter.write(filename)
                 importer = Mesher()
-                shape = importer.read("test.3mf")
+                shape = importer.read(filename)
                 self.assertEqual(shape[0].label, name)
                 self.assertEqual(importer.mesh_count, 1)
                 properties = importer.get_mesh_properties()
@@ -141,9 +152,10 @@ class TestAddShape(DirectApiTestCase):
         red_shape.color = Color("red")
         red_shape.label = "red"
         exporter.add_shape([blue_shape, red_shape])
-        exporter.write("test.3mf")
+        filename = temp_3mf_file()
+        exporter.write(filename)
         importer = Mesher()
-        box, cone = importer.read("test.3mf")
+        box, cone = importer.read(filename)
         self.assertVectorAlmostEquals(box.bounding_box().size, (1, 1, 1), 2)
         self.assertVectorAlmostEquals(box.bounding_box().size, (1, 1, 1), 2)
         self.assertEqual(len(box.clean().faces()), 6)
@@ -158,9 +170,10 @@ class TestAddShape(DirectApiTestCase):
         cone = Solid.make_cone(1, 0, 2).locate(Location((0, -1, 0)))
         shape_assembly = Compound([box, cone])
         exporter.add_shape(shape_assembly)
-        exporter.write("test.3mf")
+        filename = temp_3mf_file()
+        exporter.write(filename)
         importer = Mesher()
-        shapes = importer.read("test.3mf")
+        shapes = importer.read(filename)
         self.assertEqual(importer.mesh_count, 2)
 
 
@@ -216,7 +229,8 @@ class TestImportDegenerateTriangles(unittest.TestCase):
     "format", (Path, fsencode, fsdecode), ids=["path", "bytes", "str"]
 )
 def test_pathlike_mesher(tmp_path, format):
-    path = format(tmp_path / "test.3mf")
+    filename = temp_3mf_file()
+    path = format(tmp_path / filename)
     exporter, importer = Mesher(), Mesher()
     exporter.add_shape(Solid.make_box(1, 1, 1))
     exporter.write(path)