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"""Tests for variable parameters and selection parameters"""
import pandas as pd
import warnings
import pytest
import re
import altair.vegalite.v5 as alt
def test_variable_param():
data = pd.DataFrame([{"a": "A", "b": 28}])
rad_slider = alt.binding_range(min=0, max=20, step=1)
rad_var = alt.param(bind=rad_slider, value=0, name="paramName")
c = (
alt.Chart(data)
.mark_bar(cornerRadius=rad_var)
.encode(
x="a:N",
y="b:Q",
)
.add_params(rad_var)
)
dct = c.to_dict()
mark_dict = {"type": "bar", "cornerRadius": {"expr": "paramName"}}
param_list = [
{
"name": "paramName",
"bind": {"input": "range", "max": 20, "min": 0, "step": 1},
"value": 0,
}
]
assert dct["mark"] == mark_dict
assert dct["params"] == param_list
def test_param_expr():
height_var = alt.param(name="height")
inner_var = height_var / 2
tick_var = (3 * height_var) / 4
height_str = height_var._to_expr()
inner_str = inner_var._to_expr()
tick_str = tick_var._to_expr()
assert height_str == "height"
assert inner_str == "(height / 2)"
assert tick_str == "((3 * height) / 4)"
data = pd.DataFrame({"r1": [310, 0], "r2": [270, 0], "r3": [125, 225]})
c1 = alt.Chart(data).mark_bar(size=height_var).encode(x="r1")
c2 = alt.Chart(data).mark_bar(size=inner_var).encode(x="r2")
c3 = alt.Chart(data).mark_tick(size=tick_var).encode(x="r3")
c = (c1 + c2 + c3).add_params(height_var)
dct = c.to_dict()
expr_set = {d["mark"]["size"]["expr"] for d in dct["layer"]}
assert "height" in expr_set
assert "(height / 2)" in expr_set
assert "((3 * height) / 4)" in expr_set
def test_selection_deprecation():
# We use the `warnings.catch_warnings` context so pytest will also report deprecation warnings
with warnings.catch_warnings():
warnings.simplefilter("error")
# new syntax
alt.selection_point()
alt.selection_interval()
# this v4 syntax is deprecated
with pytest.warns(alt.utils.deprecation.AltairDeprecationWarning):
alt.selection_single()
with pytest.warns(alt.utils.deprecation.AltairDeprecationWarning):
alt.selection_multi()
# new syntax
brush = alt.selection_interval()
c = alt.Chart().mark_point()
c.add_params(brush)
# this v4 syntax is deprecated
brush = alt.selection_interval()
c = alt.Chart().mark_point()
with pytest.warns(alt.utils.deprecation.AltairDeprecationWarning):
c.add_selection(brush)
def test_parameter_naming():
# test explicit naming
prm = alt.param(name="some_name")
assert prm.param.name == "some_name"
# test automatic naming which has the form such as param_5
prm0, prm1, prm2 = [alt.param() for _ in range(3)]
res = re.match("param_([0-9]+)", prm0.param.name)
assert res
num = int(res[1])
assert prm1.param.name == f"param_{num+1}"
assert prm2.param.name == f"param_{num+2}"
def test_selection_expression():
data = pd.DataFrame([{"a": "A", "b": 28}])
sel = alt.selection_point(fields=["b"])
se = sel.b | 300
assert isinstance(se, alt.SelectionExpression)
assert isinstance(se.expr, alt.expr.core.Expression)
c = (
alt.Chart(data)
.mark_point()
.encode(
x="a:N",
y="b:Q",
size=alt.value(se),
)
.add_params(sel)
)
dct = c.to_dict()
expr_str = str(se.expr)
assert dct["encoding"]["size"]["value"]["expr"] == expr_str
def test_selection_condition():
sel = alt.selection_point(empty=False)
c = (
alt.Chart()
.mark_point()
.encode(size=alt.condition(sel, alt.value(100), alt.value(10)))
.add_params(sel)
)
dct = c.to_dict()
param_name = sel.param.name
cond = dct["encoding"]["size"]["condition"]
assert cond["value"] == 100
assert cond["param"] == param_name
# The else condition
assert dct["encoding"]["size"]["value"] == 10
def test_creation_views_params_layered_repeat_chart():
import altair as alt
from vega_datasets import data
source = alt.UrlData(data.flights_2k.url, format={"parse": {"date": "date"}})
brush = alt.selection_interval(encodings=["x"])
# Define the base chart, with the common parts of the
# background and highlights
base = (
alt.Chart(width=160, height=130)
.mark_bar()
.encode(x=alt.X(alt.repeat("column")).bin(maxbins=20), y="count()")
)
# gray background with selection
background = base.encode(color=alt.value("#ddd")).add_params(brush)
# blue highlights on the transformed data
highlight = base.transform_filter(brush)
# layer the two charts & repeat
c = (
alt.layer(background, highlight, data=source)
.transform_calculate("time", "hours(datum.date)")
.repeat(column=["distance", "delay", "time"])
)
dct = c.to_dict()
assert "child__column_distance_view_" in dct["params"][0]["views"][0]
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