Added in operator tests

Rest.http

@@ -22,7 +22,33 @@ GET /products?unit_price=is.null
 ?? body length == 0
 
 ###
+GET /products?product_name=in.(Chai,Chang)
+?? status == 200
+?? body length == 3
+{{
+    const {expect} = require('chai');
+    let responseItems = JSON.parse(response.body);
+    test("OK in", () => 
+    {
+        expect(responseItems[0].id).to.equal(1);
+        expect(responseItems[2].id).to.equal(3);
+    })
+}}
 
+###
+GET /products?id=in.(1,2,79)
+?? status == 200
+?? body length == 2
+{{
+    const {expect} = require('chai');
+    let responseItems = JSON.parse(response.body);
+    test("OK in", () => 
+    {
+        expect(responseItems[0].id).to.equal(1);
+        expect(responseItems[1].id).to.equal(2);
+    })
+}}
+###
 POST /products
 Content-Type: application/json