Allow saving generated images to dir

pytest_pyvista/pytest_pyvista.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 
-
 import os
 import pathlib
 import platform
@@ -28,6 +27,16 @@ def pytest_addoption(parser):
         action="store_true",
         help="Enables failure if image cache does not exist.",
     )
+    group.addoption(
+        "--generated_image_dir",
+        action="store",
+        help="Path to dump test images from the current run.",
+    )
+    group.addoption(
+        "--add_missing_images",
+        action="store_true",
+        help="Adds images to cache if missing.",
+    )
     group.addoption(
         "--skip_image_cache_vtk8",
         action="store_true",
@@ -75,6 +84,7 @@ class VerifyImageCache:
     reset_image_cache = False
     ignore_image_cache = False
     fail_extra_image_cache = False
+    add_missing_images = False
     skip_image_cache_vtk8 = False
 
     def __init__(
@@ -86,6 +96,7 @@ def __init__(
         warning_value=200,
         var_error_value=1000,
         var_warning_value=1000,
+        generated_image_dir=None,
     ):
         self.test_name = test_name
 
@@ -100,6 +111,11 @@ def __init__(
         self.var_error_value = var_error_value
         self.var_warning_value = var_warning_value
 
+        self.generated_image_dir = generated_image_dir
+        if self.generated_image_dir is not None and not os.path.isdir(self.generated_image_dir):
+            warnings.warn(f"pyvista test generated image dir: {self.generated_image_dir} does not yet exist.  Creating dir.")
+            os.makedirs(self.generated_image_dir)
+
         self.high_variance_test = False
         self.windows_skip_image_cache = False
         self.macos_skip_image_cache = False
@@ -151,16 +167,17 @@ def __call__(self, plotter):
         # cached image name. We remove the first 5 characters of the function name
         # "test_" to get the name for the image.
         image_filename = os.path.join(self.cache_dir, test_name[5:] + ".png")
-
         if not os.path.isfile(image_filename) and self.fail_extra_image_cache:
             raise RuntimeError(f"{image_filename} does not exist in image cache")
-        # simply save the last screenshot if it doesn't exist or the cache
-        # is being reset.
-        if self.reset_image_cache or not os.path.isfile(image_filename):
-            return plotter.screenshot(image_filename)
 
-        # otherwise, compare with the existing cached image
+        if self.add_missing_images and not os.path.isfile(image_filename):
+            plotter.screenshot(image_filename)
+
+        if self.generated_image_dir is not None:
+            gen_image_filename =os.path.join(self.generated_image_dir, test_name[5:] + ".png")
+            plotter.screenshot(gen_image_filename)
         error = pyvista.compare_images(image_filename, plotter)
+
         if error > allowed_error:
             raise RuntimeError(
                 f"{test_name} Exceeded image regression error of "
@@ -184,6 +201,9 @@ def verify_image_cache(request, pytestconfig):
     VerifyImageCache.fail_extra_image_cache = pytestconfig.getoption(
         "fail_extra_image_cache"
     )
+    VerifyImageCache.add_missing_images = pytestconfig.getoption(
+        "add_missing_images"
+    )
     VerifyImageCache.skip_image_cache_vtk8 = pytestconfig.getoption(
         "skip_image_cache_vtk8"
     )
@@ -192,7 +212,9 @@ def verify_image_cache(request, pytestconfig):
     if cache_dir is None:
         cache_dir = pytestconfig.getini("image_cache_dir")
 
-    verify_image_cache = VerifyImageCache(request.node.name, cache_dir)
+    gen_dir = pytestconfig.getoption("generated_image_dir")
+
+    verify_image_cache = VerifyImageCache(request.node.name, cache_dir, generated_image_dir=gen_dir)
     pyvista.global_theme.before_close_callback = verify_image_cache
 
     return verify_image_cache

tests/test_pyvista.py

@@ -8,6 +8,7 @@
 skip_vtk8 = pytest.mark.skipif(pv.vtk_version_info < (9,), reason="vtk8 not supported")
 skip_vtk9 = pytest.mark.skipif(pv.vtk_version_info >= (9,), reason="vtk8 only test")
 
+
 @skip_vtk8
 def test_arguments(testdir):
     """Test pytest arguments"""
@@ -189,6 +190,49 @@ def test_imcache_var(verify_image_cache):
     result = testdir.runpytest("--fail_extra_image_cache", "test_file2.py")
     result.stdout.fnmatch_lines("*[Pp]assed*")
 
+
+@skip_vtk8
+def test_generated_image_dir_commandline(testdir):
+    """Test setting generated_image_dir via CLI option."""
+    make_cached_images(testdir.tmpdir)
+    testdir.makepyfile(
+        """
+        import pyvista as pv
+        pv.OFF_SCREEN = True
+        def test_imcache(verify_image_cache):
+            sphere = pv.Sphere()
+            plotter = pv.Plotter()
+            plotter.add_mesh(sphere, color="red")
+            plotter.show()
+        """
+    )
+
+    result = testdir.runpytest("--fail_extra_image_cache", "--generated_image_dir", "gen_dir")
+    assert os.path.isdir(os.path.join(testdir.tmpdir, "gen_dir"))
+    assert os.path.isfile(os.path.join(testdir.tmpdir, "gen_dir", "imcache.png"))
+    result.stdout.fnmatch_lines("*[Pp]assed*")
+
+
+@skip_vtk8
+def test_add_missing_images_commandline(testdir):
+    """Test setting add_missing_images via CLI option."""
+    testdir.makepyfile(
+        """
+        import pyvista as pv
+        pv.OFF_SCREEN = True
+        def test_imcache(verify_image_cache):
+            sphere = pv.Sphere()
+            plotter = pv.Plotter()
+            plotter.add_mesh(sphere, color="red")
+            plotter.show()
+        """
+    )
+
+    result = testdir.runpytest("--add_missing_images")
+    assert os.path.isfile(os.path.join(testdir.tmpdir, "image_cache_dir", "imcache.png"))
+    result.stdout.fnmatch_lines("*[Pp]assed*")
+
+
 @skip_vtk9
 def test_skip_vtk8_commandline(testdir):
     """Test skip vtk8 via CLI option."""
@@ -201,7 +245,6 @@ def test_imcache(verify_image_cache):
             sphere = pv.Sphere()
             plotter = pv.Plotter()
             plotter.add_mesh(sphere, color="red")
-
             plotter.show()
         """
     )