Test lazyload (#47)

* test that lazily loaded modules are not imported by default

* pandas compability

* lazy load figure factory

tests/test_lazyload.py

@@ -0,0 +1,24 @@
+import multiprocessing
+import sys
+
+
+def check_loaded(queue, modules):
+    import xiplot  # noqa: F401
+    import xiplot.setup  # noqa: F401
+
+    queue.put([mod in sys.modules for mod in modules])
+
+
+def test_ensure_lazyload():
+    # This tests that the following packages are not imported when xiplot is
+    # imported, so that they can be lazily loaded in the WASM version.
+    # This test starts a new Python (multi-)process using "spawn" to check the
+    # imports in a clean environment.
+    modules = ["sklearn", "jsonschema", "plotly.figure_factory"]
+    ctx = multiprocessing.get_context("spawn")
+    q = ctx.Queue()
+    p = ctx.Process(target=check_loaded, args=(q, modules))
+    p.start()
+    for mod, loaded in zip(modules, q.get()):
+        assert not loaded, f"{mod} should be lazily loaded"
+    p.join()

xiplot/plots/boxplot.py

@@ -132,7 +132,8 @@ def render(
     ):
         if y_axis is None:
             return placeholder_figure("Please select y axis")
-        df = merge_df_aux(df, aux).reset_index(names="__Xiplot_index__")
+        df = merge_df_aux(df, aux)
+        df["__Xiplot_index__"] = range(df.shape[0])
         if x_axis not in df.columns:
             return placeholder_figure("Please select x axis")
         if color not in df.columns:

xiplot/plots/distplot.py

@@ -1,6 +1,5 @@
 import dash
 import plotly.express as px
-import plotly.figure_factory as ff
 from dash import ALL, MATCH, Input, Output, State, dcc
 from dash.exceptions import PreventUpdate
 
@@ -31,7 +30,7 @@
 class Distplot(APlot):
     @classmethod
     def name(cls):
-        return "Distribution plot"
+        return "Density plot"
 
     @classmethod
     def register_callbacks(cls, app, df_from_store, df_to_store):
@@ -121,7 +120,13 @@ def render(
         hover=None,
         template=None,
     ):
-        df = merge_df_aux(df, aux).reset_index(names="__Xiplot_index__")
+        # `plotly.figure_factory` checks if scipy is installed and caches the
+        # result. This causes issues if scipy is lazily loaded in WASM.
+        import scipy  # noqa: F401, isort: skip
+        import plotly.figure_factory as ff
+
+        df = merge_df_aux(df, aux)
+        df["__Xiplot_index__"] = range(df.shape[0])
         if variable not in df.columns:
             return placeholder_figure("Please select a variable")
         if color not in df.columns:

xiplot/plots/lineplot.py

@@ -125,7 +125,8 @@ def render(
         hover=None,
         template=None,
     ):
-        df = merge_df_aux(df, aux).reset_index(names="__Xiplot_index__")
+        df = merge_df_aux(df, aux)
+        df["__Xiplot_index__"] = range(df.shape[0])
         if x_axis not in df.columns or y_axis not in df.columns:
             return placeholder_figure("Please select x and y axis")
         if color not in df.columns: