def test_removes_novariance_column():
v_t = VarianceThreshold(0)
res_df = v_t.fit_transform(DATA)
assert is_frame(res_df)
assert "zero_var" not in res_df.columns
def test_works_with_reordered_feats():
v_t = VarianceThreshold(0)
v_t.fit(DATA)
res_df = v_t.transform(DATA[["non_zero_1", "zero_var", "non_zero_2"]])
assert "zero_var" not in res_df.columns
def test_variances_are_dfs():
v_t = VarianceThreshold(0)
v_t.fit(DATA)
assert is_series(v_t.variances_)