Added select tests

Select.http

@@ -0,0 +1,88 @@
+GET /products?select=id,unit_price,discontinued,supplier_id
+?? status == 200
+?? body length == 77
+{{
+    const { expect } = require('chai');
+    let actual = JSON.parse(response.body)[0];
+    let expected =  {
+    id: 1,
+    unit_price: 18,
+    discontinued: 1,
+    supplier_id: 8
+    }
+    test('OK Select', () => {
+    expect(JSON.stringify(expected)).to.equal(JSON.stringify(actual));
+    });
+}}
+###
+GET /products?select=id,unit_price,categories(category_name)
+?? status == 200
+?? body length == 77
+{{
+    const { expect } = require('chai');
+    let actual = JSON.parse(response.body)[0];
+    let expected =  {
+    id: 1,
+    unit_price: 18,
+      categories: {
+        category_name: "Beverages"
+        }
+    }
+    test('OK Select', () => {
+    expect(JSON.stringify(expected)).to.equal(JSON.stringify(actual));
+    });
+}}
+###
+GET /categories?select=id,category_name,products(product_name)
+?? status == 200
+?? body length == 8
+{{
+    const { expect } = require('chai');
+    let actual = JSON.parse(response.body)[0];
+    let expected =  {
+    id: 1,
+    category_name: "Beverages",
+      products: [
+            {
+                product_name: "Chai"
+            },
+            {
+                product_name: "Chang"
+            },
+            {
+                product_name: "Guaraná Fantástica"
+            },
+            {
+                product_name: "Sasquatch Ale"
+            },
+            {
+                product_name: "Steeleye Stout"
+            },
+            {
+                product_name: "Côte de Blaye"
+            },
+            {
+                product_name: "Chartreuse verte"
+            },
+            {
+                product_name: "Ipoh Coffee"
+            },
+            {
+                product_name: "Laughing Lumberjack Lager"
+            },
+            {
+                product_name: "Outback Lager"
+            },
+            {
+                product_name: "Rhönbräu Klosterbier"
+            },
+            {
+                product_name: "Lakkalikööri"
+            }
+        ]
+    }
+    test('OK Select', () => {
+    expect(JSON.stringify(expected)).to.equal(JSON.stringify(actual));
+    });
+}}
+