Ensure CustomLine.xdata is always ndarray

corrscope/renderer.py

@@ -215,7 +215,16 @@ UpdateOneLine = Callable[[np.ndarray], Any]
 @attr.dataclass
 class CustomLine:
     stride: int
-    xdata: np.ndarray
+    _xdata: np.ndarray = attr.ib(converter=np.array)
+
+    @property
+    def xdata(self) -> np.ndarray:
+        return self._xdata
+
+    @xdata.setter
+    def xdata(self, value):
+        self._xdata = np.array(value)
+
     set_xdata: UpdateOneLine
     set_ydata: UpdateOneLine
 

tests/test_renderer.py

@@ -20,6 +20,7 @@ from corrscope.renderer import (
     calc_center,
     AbstractMatplotlibRenderer,
     RendererFrontend,
+    CustomLine,
 )
 from corrscope.util import perr
 from corrscope.wave import Flatten
@@ -508,3 +509,19 @@ def test_frontend_overrides_backend(mocker: "pytest_mock.MockFixture"):
 
     assert frontend_get_frame.call_count == 1
     assert backend_get_frame.call_count == 1
+
+
+def test_custom_line():
+    def verify(line: CustomLine, xdata: list):
+        line_xdata = line.xdata
+        assert isinstance(line_xdata, np.ndarray)
+        assert line_xdata.tolist() == xdata
+
+    stride = 1
+    noop = lambda x: None
+
+    line = CustomLine(stride, [3], noop, noop)
+    verify(line, [3])
+
+    line.xdata = [4, 4]
+    verify(line, [4, 4])