Seirdy/func-analysis

# -*- coding: utf-8 -*-

"""Tests func_analysis.

This deliberately uses a function requiring a high degree of precision
"""

from decimal import Decimal

import numpy as np
from pytest import raises

from func_analysis import AnalyzedFunc


def test_zeroth_derivative_is_itself(all_analyzed_funcs):
    """Check that nth_derivative(0) returns the unaltered function."""
    sample_size = 50
    points = np.random.random(sample_size) * np.random.randint(
        -100, 100, sample_size
    )
    points = points[abs(points) > 1e-4]
    for analyzed_func in all_analyzed_funcs:
        np.testing.assert_array_equal(
            analyzed_func.nth_derivative(0)(points), analyzed_func.func(points)
        )


def test_unregistered_func_exception(all_analyzed_funcs):
    """Check that AnalyzedFunc.func raises exception.

    AnalyzedFunc.func raises a special TypeError for unregistered types.
    """
    for analyzed_func in all_analyzed_funcs:
        with raises(TypeError) as excinfo:
            analyzed_func.func(Decimal(2))

        assert (
            str(excinfo.value)
            == "Unsupported type '<class 'decimal.Decimal'>'. "
            + "Expected type abc.Real or Iterable[abc.Real]."
        )


def test_parabola_has_symmetry(analyzed_parab):
    """Check analyzed_parab's symmetry functions."""
    assert analyzed_parab.has_symmetry(axis=0)
    np.testing.assert_equal(
        analyzed_parab.vertical_axis_of_symmetry, analyzed_parab.crits
    )
    analyzed_parab_new = AnalyzedFunc(
        func=analyzed_parab.func, x_range=(-8, 8), zeros_wanted=2
    )
    np.testing.assert_equal(
        analyzed_parab_new.vertical_axis_of_symmetry, analyzed_parab.crits
    )