[JEDI-382] Forward pagination parameters to SCIM (#397)

https://runway.powerhrg.com/backlog_items/JEDI-382

Before, both
```
curl -X GET 'http://localhost:3000/audiences/scim/Titles?count=1' | json_pp
```
and
```
curl -X GET 'http://localhost:3000/audiences/scim/Titles?startIndex=101' | json_pp
```
returned the same response as a simple `GET /audiences/scim/Titles`. The
`count` and `startIndex` parameters are valid for paginating SCIM and
work when querying `https://id.powerhrg.com/api/scim` directly. This
change forwards both parameters (if present) so that the SCIM request
includes them.

audiences/app/controllers/audiences/scim_proxy_controller.rb

@@ -4,7 +4,7 @@ module Audiences
   class ScimProxyController < ApplicationController
     def get
       resources = Audiences::Scim.resource(params[:scim_path].to_sym)
-                                 .query(filter: params[:filter])
+                                 .query(filter: params[:filter], startIndex: params[:startIndex], count: params[:count])
 
       render json: resources, except: %w[schemas meta]
     end

audiences/spec/requests/scim_proxy_spec.rb

@@ -29,7 +29,8 @@
   context "GET /audiences/scim" do
     it "returns the Resources key from the response" do
       attrs = "id,externalId,displayName"
-      stub_request(:get, "http://example.com/scim/v2/MyResources?attributes=#{attrs}&filter=name eq John")
+      query = "attributes=#{attrs}&count&filter=name eq John&startIndex"
+      stub_request(:get, "http://example.com/scim/v2/MyResources?#{query}")
         .to_return(status: 200, body: response_body, headers: {})
 
       get audience_scim_proxy_path(scim_path: "MyResources", filter: "name eq John")
@@ -42,9 +43,32 @@
                                             ])
     end
 
+    it "returns 'count' resources" do
+      attrs = "id,externalId,displayName"
+      query = "attributes=#{attrs}&count=1&filter&startIndex"
+      stub_request(:get, "http://example.com/scim/v2/MyResources?#{query}")
+        .to_return(status: 200, body: { Resources: resources.slice(0, 1) }.to_json, headers: {})
+
+      get audience_scim_proxy_path(scim_path: "MyResources", count: 1)
+
+      expect(response.parsed_body).to match([{ "displayName" => "A Name", "externalId" => "1", "photos" => "photo 1" }])
+    end
+
+    it "returns resources starting from 'startIndex'" do
+      attrs = "id,externalId,displayName"
+      query = "attributes=#{attrs}&count&filter&startIndex=3"
+      stub_request(:get, "http://example.com/scim/v2/MyResources?#{query}")
+        .to_return(status: 200, body: { Resources: resources.slice(2, 1) }.to_json, headers: {})
+
+      get audience_scim_proxy_path(scim_path: "MyResources", startIndex: 3)
+
+      expect(response.parsed_body).to match([{ "displayName" => "YAN", "externalId" => "3", "photos" => "photo 3" }])
+    end
+
     it "removes the schemas and meta from the resources" do
       attrs = "id,externalId,displayName"
-      stub_request(:get, "http://example.com/scim/v2/MyResources?attributes=#{attrs}&filter=name eq John")
+      query = "attributes=#{attrs}&count&filter=name eq John&startIndex"
+      stub_request(:get, "http://example.com/scim/v2/MyResources?#{query}")
         .to_return(status: 200, body: response_body, headers: {})
 
       get audience_scim_proxy_path(scim_path: "MyResources", filter: "name eq John")