test: add missing tests and update descriptions

Signed-off-by: Athan <kgryte@gmail.com>

Author: kgryte

lib/node_modules/@stdlib/stats/base/nanvariancewd/test/test.ndarray.js

@@ -39,7 +39,7 @@ tape( 'the function has an arity of 5', function test( t ) {
 	t.end();
 });
 
-tape( 'the function calculates the population variance of a strided array (ignoring `NaN` values)', function test( t ) {
+tape( 'the function calculates the population variance of a strided array', function test( t ) {
 	var x;
 	var v;
 	var i;
@@ -93,7 +93,7 @@ tape( 'the function calculates the population variance of a strided array (ignor
 	t.end();
 });
 
-tape( 'the function calculates the population variance of a strided array (ignoring `NaN` values) (accessors)', function test( t ) {
+tape( 'the function calculates the population variance of a strided array (accessors)', function test( t ) {
 	var x;
 	var v;
 	var i;
@@ -147,7 +147,7 @@ tape( 'the function calculates the population variance of a strided array (ignor
 	t.end();
 });
 
-tape( 'the function calculates the sample variance of a strided array (ignoring `NaN` values)', function test( t ) {
+tape( 'the function calculates the sample variance of a strided array', function test( t ) {
 	var x;
 	var v;
 	var i;
@@ -201,7 +201,7 @@ tape( 'the function calculates the sample variance of a strided array (ignoring
 	t.end();
 });
 
-tape( 'the function calculates the sample variance of a strided array (ignoring `NaN` values) (accessors)', function test( t ) {
+tape( 'the function calculates the sample variance of a strided array (accessors)', function test( t ) {
 	var x;
 	var v;
 	var i;
@@ -270,6 +270,21 @@ tape( 'if provided an `N` parameter less than or equal to `0`, the function retu
 	t.end();
 });
 
+tape( 'if provided an `N` parameter less than or equal to `0`, the function returns `NaN` (accessors)', function test( t ) {
+	var x;
+	var v;
+
+	x = [ 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( 0, 1, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	v = nanvariancewd( -1, 1, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if provided an `N` parameter equal to `1`, the function returns a population variance of `0` provided the first element is not `NaN`', function test( t ) {
 	var x;
 	var v;
@@ -287,6 +302,23 @@ tape( 'if provided an `N` parameter equal to `1`, the function returns a populat
 	t.end();
 });
 
+tape( 'if provided an `N` parameter equal to `1`, the function returns a population variance of `0` provided the first element is not `NaN` (accessors)', function test( t ) {
+	var x;
+	var v;
+
+	x = [ 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( 1, 0, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( v, 0.0, 'returns expected value' );
+
+	x = [ NaN, 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( 1, 0, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if provided an `N` parameter equal to `1`, the function returns a sample variance equal to `NaN`', function test( t ) {
 	var x;
 	var v;
@@ -304,6 +336,23 @@ tape( 'if provided an `N` parameter equal to `1`, the function returns a sample
 	t.end();
 });
 
+tape( 'if provided an `N` parameter equal to `1`, the function returns a sample variance equal to `NaN` (accessors)', function test( t ) {
+	var x;
+	var v;
+
+	x = [ 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( 1, 1, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	x = [ NaN, 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( 1, 1, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'if provided a `correction` parameter yielding a correction term less than or equal to `0`, the function returns `NaN`', function test( t ) {
 	var x;
 	var v;
@@ -319,6 +368,21 @@ tape( 'if provided a `correction` parameter yielding a correction term less than
 	t.end();
 });
 
+tape( 'if provided a `correction` parameter yielding a correction term less than or equal to `0`, the function returns `NaN` (accessors)', function test( t ) {
+	var x;
+	var v;
+
+	x = [ 1.0, -2.0, -4.0, 5.0, 3.0 ];
+
+	v = nanvariancewd( x.length, x.length, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	v = nanvariancewd( x.length, x.length+1, toAccessorArray( x ), 1, 0 );
+	t.strictEqual( isnan( v ), true, 'returns expected value' );
+
+	t.end();
+});
+
 tape( 'the function supports a `stride` parameter', function test( t ) {
 	var x;
 	var v;