test.js

/**
* @license Apache-2.0
*
* Copyright (c) 2018 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*    http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/

'use strict';

// MODULES //

var tape = require( 'tape' );
var isnan = require( '@stdlib/math/base/assert/is-nan' );
var PINF = require( '@stdlib/constants/float64/pinf' );
var NINF = require( '@stdlib/constants/float64/ninf' );
var EPS = require( '@stdlib/constants/float64/eps' );
var abs = require( '@stdlib/math/base/special/abs' );
var isNegativeZero = require( '@stdlib/assert/is-negative-zero' );
var isPositiveZero = require( '@stdlib/assert/is-positive-zero' );
var isSameValue = require( '@stdlib/assert/is-same-value' );
var sinpi = require( './../lib/' );


// FIXTURES //

var integers = require( './fixtures/julia/integers.json' );
var decimals = require( './fixtures/julia/decimals.json' );


// TESTS //

tape( 'main export is a function', function test( t ) {
	t.ok( true, __filename );
	t.strictEqual( typeof sinpi, 'function', 'main export is a function' );
	t.end();
});

tape( 'the function returns `NaN` if provided either positive or negative infinity', function test( t ) {
	var v = sinpi( PINF );
	t.equal( isnan( v ), true, 'returns expected value' );
	v = sinpi( NINF );
	t.equal( isnan( v ), true, 'returns expected value' );
	t.end();
});

tape( 'if provided `NaN`, the function returns `NaN`', function test( t ) {
	var y = sinpi( NaN );
	t.equal( isnan( y ), true, 'returns expected value' );
	t.end();
});

tape( 'the function returns `-0` if provided `-0`', function test( t ) {
	var v = sinpi( -0.0 );
	t.strictEqual( isNegativeZero( v ), true, 'returns expected value' );
	t.end();
});

tape( 'the function returns `+0` if provided `+0`', function test( t ) {
	var v = sinpi( 0.0 );
	t.strictEqual( isPositiveZero( v ), true, 'returns expected value' );
	t.end();
});

tape( 'if provided an integer, the function returns `+-0`', function test( t ) {
	var expected;
	var x;
	var y;
	var i;

	x = integers.x;
	expected = integers.expected;
	for ( i = 0; i < x.length; i++ ) {
		y = sinpi( x[i] );
		t.equal( isSameValue( y, expected[ i ] ), true, 'returns '+expected[ i ] );
	}
	t.end();
});

tape( 'the function is odd', function test( t ) {
	var expected;
	var x;
	var y;
	var i;

	x = decimals.x;
	for ( i = 0; i < x.length; i++ ) {
		y = sinpi( -x[i] );
		expected = -sinpi( x[i] );
		t.equal( y, expected, 'returns '+expected );
	}
	t.end();
});

tape( 'the function computes `sin(πx)`', function test( t ) {
	var expected;
	var delta;
	var x;
	var y;
	var i;

	x = decimals.x;
	expected = decimals.expected;
	for ( i = 0; i < x.length; i++ ) {
		y = sinpi( x[i] );
		if ( y === expected[ i ] ) {
			t.equal( y, expected[ i ], 'x: '+x[i]+'. Expected: '+expected[i] );
		} else {
			delta = abs( y - expected[i] );
			t.ok( delta <= EPS, 'within tolerance. x: '+x[i]+'. Value: '+y+'. Expected: '+expected[i]+'. Tolerance: '+EPS+'.' );
		}
	}
	t.end();
});