test: add test case

Signed-off-by: Athan <[email protected]>

Author: kgryte

lib/node_modules/@stdlib/blas/ext/base/gapxsumkbn2/test/test.main.js

@@ -163,6 +163,27 @@ tape( 'the function supports a `stride` parameter (accessors)', function test( t
 	t.end();
 });
 
+tape( 'the function supports a negative `stride` parameter', function test( t ) {
+	var x;
+	var v;
+
+	x = [
+		1.0,  // 3
+		2.0,
+		2.0,  // 2
+		-7.0,
+		-2.0, // 1
+		3.0,
+		4.0,  // 0
+		2.0
+	];
+
+	v = gapxsumkbn2( 4, 5.0, x, -2 );
+
+	t.strictEqual( v, 25.0, 'returns expected value' );
+	t.end();
+});
+
 tape( 'the function supports a negative `stride` parameter (accessors)', function test( t ) {
 	var x;
 	var v;