test: add edge case tests for csignumf.assign including infinities

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---

Author: Deepak91168

lib/node_modules/@stdlib/math/base/special/csignumf/test/test.assign.js

@@ -27,6 +27,8 @@ var isNegativeZerof = require( '@stdlib/math/base/assert/is-negative-zerof' );
 var isPositiveZerof = require( '@stdlib/math/base/assert/is-positive-zerof' );
 var absf = require( '@stdlib/math/base/special/absf' );
 var EPS = require( '@stdlib/constants/float32/eps' );
+var PINF = require( '@stdlib/constants/float32/pinf' );
+var NINF = require( '@stdlib/constants/float32/ninf' );
 var csignumf = require( './../lib' );
 
 
@@ -113,3 +115,21 @@ tape( 'the function returns -0 if input is -0 -0i', function test( t ) {
 	t.strictEqual( isNegativeZerof( outNegZero[ 1 ] ), true, 'imag is -0' );
 	t.end();
 });
+
+tape( 'the function returns NaNs if input is infinity', function test( t ) {
+	var outInf = new Float32Array( 2 );
+	csignumf.assign( PINF, PINF, outInf, 1, 0 );
+
+	t.strictEqual( isnanf( outInf[ 0 ] ), true, 'real is NaN' );
+	t.strictEqual( isnanf( outInf[ 1 ] ), true, 'imag is NaN' );
+	t.end();
+});
+
+tape( 'the function returns NaNs if input is negative infinity', function test( t ) {
+	var outNegInf = new Float32Array( 2 );
+	csignumf.assign( NINF, NINF, outNegInf, 1, 0 );
+
+	t.strictEqual( isnanf( outNegInf[ 0 ] ), true, 'real is NaN' );
+	t.strictEqual( isnanf( outNegInf[ 1 ] ), true, 'imag is NaN' );
+	t.end();
+});