From 61fdaed53c07da46e25cec5c426a0f7f1d4cfef8 Mon Sep 17 00:00:00 2001
From: Patrick Shriwise <pshriwise@gmail.com>
Date: Thu, 2 Jan 2025 13:58:01 -0600
Subject: [PATCH] Adding XML roundtrip test for PhongPlot

---
 openmc/plots.py                | 24 +++++++++++++++++++++++-
 tests/unit_tests/test_plots.py | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/openmc/plots.py b/openmc/plots.py
index 1f492b4a386..ab64b109602 100644
--- a/openmc/plots.py
+++ b/openmc/plots.py
@@ -1478,6 +1478,24 @@ def to_xml_element(self):
 
         return element
 
+    def _read_phong_attributes(self, elem):
+        """Read attributes specific to the Phong plot
+        from an XML element
+        Returns
+        -------
+        None
+        """
+        if elem.find('light_position') is not None:
+            self.light_position = get_elem_tuple(elem, 'light_position', float)
+
+        diffuse_fraction = elem.find('diffuse_fraction')
+        if diffuse_fraction is not None:
+            self.diffuse_fraction = float(diffuse_fraction.text)
+
+        if elem.find('opaque_ids') is not None:
+            self.opaque_domains = list(get_elem_tuple(elem, 'opaque_ids', int))
+
+
     @classmethod
     def from_xml_element(cls, elem):
         """Generate plot object from an XML element
@@ -1495,16 +1513,20 @@ def from_xml_element(cls, elem):
         """
 
         plot_id = int(elem.get("id"))
-        plot = cls(plot_id)
+        plot_name = get_text(elem, 'name', '')
+        plot = cls(plot_id, plot_name)
         plot.type = "phong"
 
         plot._read_xml_attributes(elem)
+        plot._read_phong_attributes(elem)
 
         # Set plot colors
         for color_elem in elem.findall("color"):
             uid = color_elem.get("id")
             plot.colors[uid] = get_elem_tuple(color_elem, "rgb")
 
+        return plot
+
 
 class Plots(cv.CheckedList):
     """Collection of Plots used for an OpenMC simulation.
diff --git a/tests/unit_tests/test_plots.py b/tests/unit_tests/test_plots.py
index a1e15016a2e..50c1dc1112d 100644
--- a/tests/unit_tests/test_plots.py
+++ b/tests/unit_tests/test_plots.py
@@ -223,6 +223,39 @@ def test_voxel_plot_roundtrip():
     assert new_plot.color_by == plot.color_by
 
 
+def test_phone_plot_roundtrip():
+    plot = openmc.PhongPlot(name='my phong plot')
+    plot.id = 2300
+    plot.filename = 'phong1'
+    plot.pixels = (50, 50)
+    plot.look_at = (11., 12., 13.)
+    plot.camera_position = (22., 23., 24.)
+    plot.diffuse_fraction = 0.5
+    plot.horizontal_field_of_view = 90.0
+    plot.color_by = 'material'
+    plot.light_position = (8., 9., 10.)
+    plot.opaque_domains = [6, 7, 8]
+
+    elem = plot.to_xml_element()
+
+    new_plot = openmc.PhongPlot.from_xml_element(elem)
+
+    assert new_plot.name == plot.name
+    assert new_plot.id == plot.id
+    assert new_plot.filename == plot.filename
+    assert new_plot.pixels == plot.pixels
+    assert new_plot.look_at == plot.look_at
+    assert new_plot.camera_position == plot.camera_position
+    assert new_plot.diffuse_fraction == plot.diffuse_fraction
+    assert new_plot.horizontal_field_of_view == plot.horizontal_field_of_view
+    assert new_plot.color_by == plot.color_by
+    assert new_plot.light_position == plot.light_position
+    assert new_plot.opaque_domains == plot.opaque_domains
+
+    # ensure the new object is valid to re-write to XML
+    new_elem = new_plot.to_xml_element()
+
+
 def test_plot_directory(run_in_tmpdir):
     pwr_pin = openmc.examples.pwr_pin_cell()