Ensuring all classes are accessible after importing only the main PyS…

…DM package. Closes #1124 (#1135)

PySDM/__init__.py

@@ -2,7 +2,7 @@
 """
 PySDM offers a set of building blocks for development of atmospheric cloud
 simulation systems revolving around the particle-based microphysics modelling concept
-and the Super-Droplet Method algorithm ([Shima et al. 2009](http://doi.org/10.1002/qj.441))
+and the Super-Droplet Method algorithm ([Shima et al. 2009](https://doi.org/10.1002/qj.441))
 for numerically tackling the probabilistic representation of particle coagulation.
 
 For an overview of PySDM, see [Bartman, Arabas et al. 2021](https://arxiv.org/abs/2103.17238).
@@ -14,7 +14,7 @@
 [README.md file](https://github.com/open-atmos/PySDM/blob/master/README.md)
 which also includes basic usage examples in **Python**, **Julia** and **Matlab**.
 
-A set of more elaborate examples engineered in Python and accompanied with Jupyter
+A set of more elaborate examples engineered in Python and accompanied by Jupyter
 notebooks are maintained in the
 [PySDM-examples package](https://github.com/open-atmos/PySDM-examples).
 
@@ -24,6 +24,7 @@
 
 from pkg_resources import DistributionNotFound, VersionConflict, get_distribution
 
+from . import environments, exporters, products
 from .builder import Builder
 from .formulae import Formulae
 from .particulator import Particulator

PySDM/dynamics/collisions/__init__.py

@@ -7,3 +7,5 @@
 breakup fragmentations `PySDM.dynamics.collisions.breakup_fragmentations`
 """
 from PySDM.dynamics.collisions.collision import Breakup, Coalescence, Collision
+
+from . import collision_kernels

PySDM/environments/__init__.py

@@ -4,5 +4,6 @@
 `PySDM.environments.parcel.Parcel`, ...
 """
 from .box import Box
+from .kinematic_1d import Kinematic1D
 from .kinematic_2d import Kinematic2D
 from .parcel import Parcel

PySDM/initialisation/__init__.py

@@ -2,6 +2,9 @@
 initialisation logic, particle size spectra, sampling methods and
 wet radii equilibration
 """
+from . import sampling, spectra
 from .discretise_multiplicities import discretise_multiplicities
 from .equilibrate_wet_radii import equilibrate_wet_radii
 from .init_fall_momenta import init_fall_momenta
+
+from . import aerosol_composition  # isort:skip

tests/unit_tests/test_imports.py

@@ -0,0 +1,47 @@
+""" test ensuring that all needed __init__.py entries are in place """
+import pytest
+
+import PySDM
+
+CLASSES = (
+    "Builder",
+    "Formulae",
+    "Particulator",
+    "attributes.chemistry.Acidity",
+    "attributes.physics.DryVolume",
+    "backends.CPU",
+    "backends.GPU",
+    "dynamics.Condensation",
+    "dynamics.collisions.breakup_fragmentations.AlwaysN",
+    "dynamics.collisions.coalescence_efficiencies.LowList1982Ec",
+    "dynamics.collisions.collision_kernels.Golovin",
+    "dynamics.terminal_velocity.RogersYau",
+    "environments.Box",
+    "environments.Kinematic1D",
+    "environments.Kinematic2D",
+    "environments.Parcel",
+    "exporters.VTKExporter",
+    "initialisation.aerosol_composition.DryAerosolMixture",
+    "initialisation.init_fall_momenta",
+    "initialisation.sampling.spectral_sampling.DeterministicSpectralSampling",
+    "initialisation.spectra.Lognormal",
+    "physics.constants_defaults",
+    "physics.diffusion_thermics.LoweEtAl2019",
+    "physics.si",
+    "products.size_spectral.EffectiveRadius",
+)
+
+
+class TestImports:
+    @staticmethod
+    @pytest.mark.parametrize("obj_path", CLASSES)
+    def test_imports(obj_path):
+        """one can import PySDM and then access classes from submodules,
+        like PySDM.environments.Box, etc"""
+        obj = PySDM
+        for attr in obj_path.split("."):
+            obj = getattr(obj, attr)
+
+    @staticmethod
+    def test_classes_sorted():
+        assert tuple(sorted(CLASSES)) == CLASSES