test: increase coverage for buffer.js

Add coverage for non-numeric byteOffset and length when using Buffer.from() with an ArrayBuffer. PR-URL: #12476 Reviewed-By: Colin Ihrig <[email protected]> Reviewed-By: James M Snell <[email protected]>

Author: Trott

test/parallel/test-buffer-arraybuffer.js

@@ -105,3 +105,41 @@ b.writeDoubleBE(11.11, 0, true);
 returntrue;
 });
 }
+
+{
+// If byteOffset is not numeric, it defaults to 0.
+constab=newArrayBuffer(10);
+constexpected=Buffer.from(ab,0);
+assert.deepStrictEqual(Buffer.from(ab,'fhqwhgads'),expected);
+assert.deepStrictEqual(Buffer.from(ab,NaN),expected);
+assert.deepStrictEqual(Buffer.from(ab,{}),expected);
+assert.deepStrictEqual(Buffer.from(ab,[]),expected);
+
+// If byteOffset can be converted to a number, it will be.
+assert.deepStrictEqual(Buffer.from(ab,[1]),Buffer.from(ab,1));
+
+// If byteOffset is Infinity, throw.
+assert.throws(
+()=>{Buffer.from(ab,Infinity);},
+/^RangeError:'offset'isoutofbounds$/
+);
+}
+
+{
+// If length is not numeric, it defaults to 0.
+constab=newArrayBuffer(10);
+constexpected=Buffer.from(ab,0,0);
+assert.deepStrictEqual(Buffer.from(ab,0,'fhqwhgads'),expected);
+assert.deepStrictEqual(Buffer.from(ab,0,NaN),expected);
+assert.deepStrictEqual(Buffer.from(ab,0,{}),expected);
+assert.deepStrictEqual(Buffer.from(ab,0,[]),expected);
+
+// If length can be converted to a number, it will be.
+assert.deepStrictEqual(Buffer.from(ab,0,[1]),Buffer.from(ab,0,1));
+
+//If length is Infinity, throw.
+assert.throws(
+()=>{Buffer.from(ab,0,Infinity);},
+/^RangeError:'length'isoutofbounds$/
+);
+}