test: add tests for the decompose function

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Author: gunjjoshi

lib/node_modules/@stdlib/fft/base/fftpack/decompose/lib/main.js

@@ -61,6 +61,9 @@
 // MODULES //
 
 var floor = require( '@stdlib/math/base/special/floor' );
+var isNonNegativeInteger = require( '@stdlib/math/base/assert/is-nonnegative-integer' );
+var isNonNegativeIntegerArray = require( '@stdlib/assert/is-nonnegative-integer-array' ).primitives;
+var isCollection = require( '@stdlib/assert/is-collection' );
 
 
 // MAIN //
@@ -131,6 +134,12 @@ function decompose( N, initial, out, stride, offset ) {
 	var i;
 	var j;
 
+	if ( !isNonNegativeInteger( N ) || !isNonNegativeIntegerArray( initial ) ||
+		!isCollection( out ) || !isNonNegativeInteger( stride ) ||
+		!isNonNegativeInteger( offset ) ) {
+		return NaN;
+	}
+
 	// Resolve the number of trial divisors:
 	ntrials = initial.length;
 

lib/node_modules/@stdlib/fft/base/fftpack/decompose/test/test.js

@@ -0,0 +1,260 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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 decompose = require( './../lib' );
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+	t.ok( true, __filename );
+	t.strictEqual( typeof decompose, 'function', 'main export is a function' );
+	t.end();
+});
+
+tape( 'if provided a sequence length which is not a nonnegative integer, the function returns NaN', function test( t ) {
+	var factors;
+	var initial;
+	var result;
+	var values;
+	var i;
+
+	values = [
+		'5',
+		-5,
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[],
+		function foo() {}
+	];
+
+	initial = [ 3, 4, 2, 5 ];
+	factors = [ 0, 0, 0, 0, 0 ];
+
+	for ( i = 0; i < values.length; i++ ) {
+		result = decompose( values[ i ], initial, factors, 1, 0 );
+		t.strictEqual( isnan( result ), true, 'returns NaN when provided ' + values[ i ] );
+	}
+	t.end();
+});
+
+tape( 'if provided an array of initial trial divisors which is not an array of nonnegative integers, the function returns NaN', function test( t ) {
+	var factors;
+	var result;
+	var values;
+	var i;
+
+	values = [
+		'5',
+		5,
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[ '1', '2' ],
+		[ -1, 2, 3 ],
+		[ 1.1, 2, 3 ],
+		function foo() {}
+	];
+
+	factors = [ 0, 0, 0, 0, 0 ];
+
+	for ( i = 0; i < values.length; i++ ) {
+		result = decompose( 10, values[ i ], factors, 1, 0 );
+		t.strictEqual( isnan( result ), true, 'returns NaN when provided ' + values[ i ] );
+	}
+	t.end();
+});
+
+tape( 'if provided an output array which is not a collection, the function returns NaN', function test( t ) {
+	var initial;
+	var result;
+	var values;
+	var i;
+
+	values = [
+		'5',
+		5,
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		function foo() {}
+	];
+
+	initial = [ 3, 4, 2, 5 ];
+
+	for ( i = 0; i < values.length; i++ ) {
+		result = decompose( 10, initial, values[ i ], 1, 0 );
+		t.strictEqual( isnan( result ), true, 'returns NaN when provided ' + values[ i ] );
+	}
+	t.end();
+});
+
+tape( 'if provided a stride which is not an integer, the function returns NaN', function test( t ) {
+	var factors;
+	var initial;
+	var result;
+	var values;
+	var i;
+
+	values = [
+		'5',
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[],
+		function foo() {}
+	];
+
+	initial = [ 3, 4, 2, 5 ];
+	factors = [ 0, 0, 0, 0, 0 ];
+
+	for ( i = 0; i < values.length; i++ ) {
+		result = decompose( 10, initial, factors, values[ i ], 0 );
+		t.strictEqual( isnan( result ), true, 'returns NaN when provided ' + values[ i ] );
+	}
+	t.end();
+});
+
+tape( 'if provided an offset which is not a nonnegative integer, the function returns NaN', function test( t ) {
+	var factors;
+	var initial;
+	var result;
+	var values;
+	var i;
+
+	values = [
+		'5',
+		-5,
+		3.14,
+		NaN,
+		true,
+		false,
+		null,
+		void 0,
+		{},
+		[],
+		function foo() {}
+	];
+
+	initial = [ 3, 4, 2, 5 ];
+	factors = [ 0, 0, 0, 0, 0 ];
+
+	for ( i = 0; i < values.length; i++ ) {
+		result = decompose( 10, initial, factors, 1, values[ i ] );
+		t.strictEqual( isnan( result ), true, 'returns NaN when provided ' + values[ i ] );
+	}
+	t.end();
+});
+
+tape( 'the function correctly factorizes a sequence length into a product of integers', function test( t ) {
+	var initial;
+	var factors;
+	var nf;
+
+	initial = [ 3, 4, 2, 5 ];
+	factors = [ 0, 0, 0, 0, 0, 0, 0 ];
+	nf = decompose( 630, initial, factors, 1, 0 );
+
+	t.strictEqual( nf, 5, 'returns expected number of factors' );
+	t.strictEqual( factors[ 0 ], 630, 'stores sequence length' );
+	t.strictEqual( factors[ 1 ], 5, 'stores number of factors' );
+	t.strictEqual( factors[ 2 ], 2, 'stores first factor' );
+	t.strictEqual( factors[ 3 ], 3, 'stores second factor' );
+	t.strictEqual( factors[ 4 ], 3, 'stores third factor' );
+	t.strictEqual( factors[ 5 ], 5, 'stores fourth factor' );
+	t.strictEqual( factors[ 6 ], 7, 'stores fifth factor' );
+
+	initial = [ 3, 4, 2, 5 ];
+	factors = [ 0, 0, 0, 0 ];
+	nf = decompose( 8, initial, factors, 1, 0 );
+
+	t.strictEqual( nf, 2, 'returns expected number of factors' );
+	t.strictEqual( factors[ 0 ], 8, 'stores sequence length' );
+	t.strictEqual( factors[ 1 ], 2, 'stores number of factors' );
+	t.strictEqual( factors[ 2 ], 2, 'stores first factor' );
+	t.strictEqual( factors[ 3 ], 4, 'stores second factor' );
+
+	t.end();
+});
+
+tape( 'the function correctly factorizes prime numbers', function test( t ) {
+	var initial;
+	var factors;
+	var primes;
+	var nf;
+	var i;
+
+	initial = [ 3, 4, 2, 5 ];
+	primes = [ 7, 11, 13, 17, 19, 23, 29, 31 ];
+
+	for ( i = 0; i < primes.length; i++ ) {
+		factors = [ 0, 0, 0 ];
+		nf = decompose( primes[ i ], initial, factors, 1, 0 );
+
+		t.strictEqual( nf, 1, 'returns expected number of factors for prime ' + primes[ i ] );
+		t.strictEqual( factors[ 0 ], primes[ i ], 'stores sequence length' );
+		t.strictEqual( factors[ 1 ], 1, 'stores number of factors' );
+		t.strictEqual( factors[ 2 ], primes[ i ], 'stores the prime as its own factor' );
+	}
+
+	t.end();
+});
+
+tape( 'the function correctly handles stride and offset parameters', function test( t ) {
+	var initial;
+	var factors;
+	var stride = 2;
+	var offset = 1;
+	var nf;
+
+	initial = [ 3, 4, 2, 5 ];
+
+	factors = [ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ];
+	nf = decompose( 12, initial, factors, stride, offset );
+
+	t.strictEqual( nf, 2, 'returns expected number of factors' );
+	t.strictEqual( factors[ offset ], 12, 'stores sequence length at offset' );
+	t.strictEqual( factors[ offset+stride ], 2, 'stores number of factors at offset + stride' );
+	t.strictEqual( factors[ offset+(2*stride) ], 3, 'stores first factor at offset + 2*stride' );
+	t.strictEqual( factors[ offset+(3*stride) ], 4, 'stores second factor at offset + 3*stride' );
+
+	t.end();
+});