Handle mathjax arg when passed to Kaleido constructor (#320)

* pop 'mathjax' arg from kwargs in Kaleido constructor, and pass to PageGenerator()

* test passing different mathjax url to calc_fig_sync()

Author: emilykl

src/py/kaleido/kaleido.py

@@ -106,6 +106,7 @@ def __init__(self, *args, **kwargs):  # noqa: D417 no args/kwargs in description
         self._height = kwargs.pop("height", None)
         self._width = kwargs.pop("width", None)
         self._stepper = kwargs.pop("stepper", False)
+        self._mathjax = kwargs.pop("mathjax", None)
         if not kwargs.get("headless", True) and (self._height or self._width):
             warnings.warn(
                 "Height and Width can only be used if headless=True, "
@@ -135,7 +136,7 @@ def __init__(self, *args, **kwargs):  # noqa: D417 no args/kwargs in description
             index = self.tmp_dir.path / "index.html"
             self._index = index.as_uri()
             if not page:
-                page = PageGenerator()
+                page = PageGenerator(mathjax=self._mathjax)
             page.generate_index(index)
 
     async def _conform_tabs(self, tabs=None) -> None:

src/py/tests/test_calc_fig.py

@@ -22,7 +22,11 @@ async def test_calc_fig():
     img_awaited = await kaleido.calc_fig(fig)
     assert isinstance(img_awaited, bytes)
 
-    img_sync = kaleido.calc_fig_sync(fig)
+    # Make sure passing `mathjax` argument via `kopts` works properly
+    img_sync = kaleido.calc_fig_sync(
+        fig,
+        kopts={"mathjax": "https://cdn.jsdelivr.net/npm/[email protected]/es5/tex-svg.js"},
+    )
     assert isinstance(img_sync, bytes)
 
     img_from_dict = kaleido.calc_fig_sync(fig.to_dict())