Add unreserve_path to Pub API adapter

This adds a new method to the Pub API adapter to complement the new
endpoint to unreserve a path in the Publishing API.

lib/gds_api/json_client.rb

@@ -64,8 +64,8 @@ def patch_json(url, params, additional_headers = {})
       do_json_request(:patch, url, params, additional_headers)
     end
 
-    def delete_json(url, additional_headers = {})
-      do_json_request(:delete, url, nil, additional_headers)
+    def delete_json(url, params = {}, additional_headers = {})
+      do_json_request(:delete, url, params, additional_headers)
     end
 
     def delete_json_with_params!(url, params, additional_headers = {})

lib/gds_api/publishing_api.rb

@@ -12,8 +12,17 @@ def destroy_intent(base_path)
     e
   end
 
+  def unreserve_path(base_path, publishing_app)
+    payload = { publishing_app: publishing_app }
+    delete_json(unreserve_url(base_path), payload)
+  end
+
 private
 
+  def unreserve_url(base_path)
+    "#{endpoint}/paths#{base_path}"
+  end
+
   def intent_url(base_path)
     "#{endpoint}/publish-intent#{base_path}"
   end

lib/gds_api/rummager.rb

@@ -19,6 +19,7 @@ def add_document(type, id, document)
       def delete_document(type, id)
         delete_json(
           "#{documents_url}/#{id}",
+          nil,
           _type: type,
         )
       end

test/json_client_test.rb

@@ -425,7 +425,8 @@ def test_client_can_set_custom_headers_on_deletes
     stub_request(:delete, "http://some.other.endpoint/some.json").to_return(status: 200)
 
     GdsApi::JsonClient.new.delete_json("http://some.other.endpoint/some.json",
-                                                  "HEADER-A" => "B", "HEADER-C" => "D")
+                                       {},
+                                       "HEADER-A" => "B", "HEADER-C" => "D")
 
     assert_requested(:delete, %r{/some.json}) do |request|
       headers_with_uppercase_names = Hash[request.headers.collect { |key, value| [key.upcase, value] }]

test/publishing_api_test.rb

@@ -11,6 +11,91 @@
     @api_client = GdsApi::PublishingApi.new(publishing_api_host)
   end
 
+  describe "#unreserve_path" do
+    it "responds with 200 OK if reservation is owned by the app" do
+      publishing_app = "publisher"
+      base_path = "/test-item"
+
+      publishing_api
+        .given("/test-item has been reserved by the Publisher application")
+        .upon_receiving("a request to unreserve a path")
+        .with(
+          method: :delete,
+          path: "/paths#{base_path}",
+          body: { publishing_app: publishing_app },
+          headers: {
+            "Content-Type" => "application/json"
+          },
+        )
+        .will_respond_with(
+          status: 200,
+          body: {},
+          headers: {
+            "Content-Type" => "application/json; charset=utf-8"
+          },
+        )
+
+      response = @api_client.unreserve_path(base_path, publishing_app)
+      assert_equal 200, response.code
+    end
+
+    it "raises an error if the reservation does not exist" do
+      publishing_app = "publisher"
+      base_path = "/test-item"
+
+      publishing_api
+        .given("no content exists")
+        .upon_receiving("a request to unreserve a non-existant path")
+        .with(
+          method: :delete,
+          path: "/paths#{base_path}",
+          body: { publishing_app: publishing_app },
+          headers: {
+            "Content-Type" => "application/json"
+          },
+        )
+        .will_respond_with(
+          status: 404,
+          body: {},
+          headers: {
+            "Content-Type" => "application/json; charset=utf-8"
+          },
+        )
+
+       assert_raises GdsApi::HTTPNotFound do
+         @api_client.unreserve_path(base_path, publishing_app)
+       end
+    end
+
+    it "raises an error if the reservation is with another app" do
+      publishing_app = "whitehall"
+      base_path = "/test-item"
+
+      publishing_api
+        .given("/test-item has been reserved by the Publisher application")
+        .upon_receiving("a request to unreserve a path owned by another app")
+        .with(
+          method: :delete,
+          path: "/paths#{base_path}",
+          body: { publishing_app: "whitehall" },
+          headers: {
+            "Content-Type" => "application/json"
+          },
+        )
+        .will_respond_with(
+          status: 422,
+          body: {},
+          headers: {
+            "Content-Type" => "application/json; charset=utf-8"
+          },
+        )
+
+       assert_raises GdsApi::HTTPUnprocessableEntity do
+         @api_client.unreserve_path(base_path, publishing_app)
+       end
+    end
+  end
+
   describe "#put_intent" do
     it "responds with 200 OK if publish intent is valid" do
       base_path = "/test-intent"