Extract finding directories for test data

Summary: Make common functions for finding directories where test data is found, instead of lots of tests using their own `__file__`  while trying to get ./tests/data and the tutorials data.

Reviewed By: nikhilaravi

Differential Revision: D27633701

fbshipit-source-id: 1467bb6018cea16eba3cab097d713116d51071e9

tests/test_render_meshes.py

@@ -6,11 +6,15 @@ Sanity checks for output images from the renderer.
 """
 import os
 import unittest
-from pathlib import Path
 
 import numpy as np
 import torch
-from common_testing import TestCaseMixin, load_rgb_image
+from common_testing import (
+    TestCaseMixin,
+    load_rgb_image,
+    get_pytorch3d_dir,
+    get_tests_dir,
+)
 from PIL import Image
 from pytorch3d.io import load_obj
 from pytorch3d.renderer.cameras import (
@@ -46,7 +50,7 @@ from pytorch3d.utils.torus import torus
 # If DEBUG=True, save out images generated in the tests for debugging.
 # All saved images have prefix DEBUG_
 DEBUG = False
-DATA_DIR = Path(__file__).resolve().parent / "data"
+DATA_DIR = get_tests_dir() / "data"
 
 
 class TestRenderMeshes(TestCaseMixin, unittest.TestCase):
@@ -384,7 +388,7 @@ class TestRenderMeshes(TestCaseMixin, unittest.TestCase):
         The pupils in the eyes of the cow should always be looking to the left.
         """
         device = torch.device("cuda:0")
-        obj_dir = Path(__file__).resolve().parent.parent / "docs/tutorials/data"
+        obj_dir = get_pytorch3d_dir() / "docs/tutorials/data"
         obj_filename = obj_dir / "cow_mesh/cow.obj"
 
         # Load mesh + texture
@@ -966,7 +970,7 @@ class TestRenderMeshes(TestCaseMixin, unittest.TestCase):
         Also check that the backward pass for texture atlas rendering is differentiable.
         """
         device = torch.device("cuda:0")
-        obj_dir = Path(__file__).resolve().parent.parent / "docs/tutorials/data"
+        obj_dir = get_pytorch3d_dir() / "docs/tutorials/data"
         obj_filename = obj_dir / "cow_mesh/cow.obj"
 
         # Load mesh and texture as a per face texture atlas.