Update `Ajax::RelationshipController` to use usernames; Test Use Case

app/controllers/ajax/relationship_controller.rb

@@ -8,8 +8,10 @@ class Ajax::RelationshipController < AjaxController
   before_action :authenticate_user!
 
   def create
+    params.require :target_user
+
     UseCase::Relationship::Create.call(
-      current_user_id: current_user.id,
+      current_user: current_user.screen_name,
       target_user: params[:target_user],
       type: params[:type]
     )
@@ -23,7 +25,7 @@ class Ajax::RelationshipController < AjaxController
 
   def destroy
     UseCase::Relationship::Destroy.call(
-      current_user_id: current_user.id,
+      current_user: current_user.screen_name,
       target_user: params[:target_user],
       type: params[:type]
     )

app/controllers/ajax_controller.rb

@@ -18,6 +18,30 @@ class AjaxController < ApplicationController
     return_response
   end
 
+  rescue_from(KeyError) do |e|
+    Sentry.capture_exception(e)
+
+    @response = {
+      success: false,
+      message: "Missing parameter: #{e.key}",
+      status: :err
+    }
+
+    return_response
+  end
+
+  rescue_from(Dry::Types::CoercionError, Dry::Types::ConstraintError) do |e|
+    Sentry.capture_exception(e)
+
+    @response = {
+      success: false,
+      message: "Invalid parameter",
+      status: :err
+    }
+
+    return_response
+  end
+
   rescue_from(ActiveRecord::RecordNotFound) do |e|
     Sentry.capture_exception(e)
 

lib/errors.rb

@@ -19,9 +19,6 @@ module Errors
     end
   end
 
-  class ParamIsMissing < BadRequest
-  end
-
   class InvalidBanDuration < BadRequest
   end
 

lib/types.rb

@@ -4,4 +4,6 @@ require 'dry-types'
 
 module Types
   include Dry.Types()
+
+  RelationshipTypes = Types::String.enum('follow')
 end

lib/use_case/base.rb

@@ -15,13 +15,5 @@ module UseCase
     def call
       raise NotImplementedError
     end
-
-    private
-
-    def not_blank!(*args)
-      args.each do |arg|
-        raise Errors::ParamIsMissing if instance_variable_get("@#{arg}").blank?
-      end
-    end
   end
 end

lib/use_case/relationship/create.rb

@@ -6,15 +6,11 @@ require "errors"
 module UseCase
   module Relationship
     class Create < UseCase::Base
-      option :current_user_id, type: Types::Coercible::Integer
+      option :current_user, type: Types::Coercible::String
       option :target_user, type: Types::Coercible::String
-      option :type, type: Types::Coercible::String
+      option :type, type: Types::RelationshipTypes
 
       def call
-        not_blank! :current_user_id, :target_user, :type
-
-        type = @type.downcase
-        ensure_type(type)
         source_user = find_source_user
         target_user = find_target_user
 
@@ -31,19 +27,14 @@ module UseCase
 
       private
 
-      def ensure_type(type)
-        raise Errors::BadRequest unless type == 'follow'
-      end
-
       def find_source_user
-        user_id = @current_user_id
-        ::User.find(user_id)
+        return current_user if current_user.is_a?(::User)
+        ::User.find_by!(screen_name: current_user)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end
 
       def find_target_user
-        target_user = @target_user
         return target_user if target_user.is_a?(::User)
         ::User.find_by!(screen_name: target_user)
       rescue ActiveRecord::RecordNotFound

lib/use_case/relationship/destroy.rb

@@ -6,15 +6,11 @@ require "errors"
 module UseCase
   module Relationship
     class Destroy < UseCase::Base
-      option :current_user_id, type: Types::Coercible::Integer
-      option :target_user, type: Types::Coercible::String
-      option :type, type: Types::Coercible::String
+      option :current_user, type: Types::Coercible::String | Types.Instance(User)
+      option :target_user, type: Types::Coercible::String | Types.Instance(User)
+      option :type, type: Types::RelationshipTypes
 
       def call
-        not_blank! :current_user_id, :target_user, :type
-
-        type = @type.downcase
-        ensure_type(type)
         source_user = find_source_user
         target_user = find_target_user
 
@@ -31,20 +27,13 @@ module UseCase
 
       private
 
-      def ensure_type(type)
-        raise Errors::BadRequest unless type == 'follow'
-      end
-
       def find_source_user
-        user_id = @current_user_id
-        ::User.find(user_id)
+        ::User.find_by!(screen_name: current_user)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound
       end
 
       def find_target_user
-        target_user = @target_user
-        return target_user if target_user.is_a?(::User)
         ::User.find_by!(screen_name: target_user)
       rescue ActiveRecord::RecordNotFound
         raise Errors::UserNotFound

spec/controllers/ajax/relationship_controller_spec.rb

@@ -5,9 +5,9 @@ require "rails_helper"
 
 describe Ajax::RelationshipController, type: :controller do
   shared_examples_for "params is empty" do
-    let(:params) { { type: type } } # type is still required as it's part of the route
+    let(:params) { }
 
-    include_examples "ajax does not succeed", "param is missing"
+    include_examples "ajax does not succeed", "is required"
   end
 
   let!(:user) { FactoryBot.create(:user) }
@@ -60,7 +60,7 @@ describe Ajax::RelationshipController, type: :controller do
         let(:type) { "dick" }
 
         it_behaves_like "params is empty"
-        include_examples "ajax does not succeed", "Bad Request"
+        include_examples "ajax does not succeed", "Invalid parameter"
       end
     end
   end
@@ -85,8 +85,6 @@ describe Ajax::RelationshipController, type: :controller do
         end
       end
 
-      it_behaves_like "params is empty"
-
       context "target_user does not exist" do
         let(:target_user) { "peter-witzig" }
 
@@ -114,8 +112,7 @@ describe Ajax::RelationshipController, type: :controller do
       context "type = 'dick'" do
         let(:type) { "dick" }
 
-        it_behaves_like "params is empty"
-        include_examples "ajax does not succeed", "Bad Request"
+        include_examples "ajax does not succeed", "Invalid parameter"
       end
     end
   end

spec/lib/use_case/relationship/create_spec.rb

@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+require "use_case/relationship/create"
+require "errors"
+
+describe UseCase::Relationship::Create do
+  shared_examples_for "valid relationship type" do
+    context "current_user does not exist" do
+      let(:current_user) { "Schweinsbraten" }
+
+      include_examples "raises an error", Errors::UserNotFound
+    end
+
+    context "target_user does not exist" do
+      let(:target_user)  { "peterwitzig" }
+
+      include_examples "raises an error", Errors::UserNotFound
+    end
+
+    context "target_user is current_user" do
+      let(:target_user)  { user1.screen_name }
+
+      include_examples "raises an error", Errors::SelfAction
+    end
+
+    context "target_user is different from current_user" do
+      its([:status]) { is_expected.to eq(201) }
+      its([:extra])  { is_expected.to eq(target_user: user2) }
+
+      it "creates a relationship" do
+        expect { subject }.to change { Relationship.count }.by(1)
+        last_relationship = Relationship.last
+        expect(last_relationship.source_id).to eq(user1.id)
+        expect(last_relationship.target_id).to eq(user2.id)
+      end
+    end
+  end
+
+  let(:base_params) do
+    {
+      current_user:    current_user,
+      target_user:     target_user,
+      type:            type
+    }
+  end
+  let(:params)          { base_params }
+  let(:current_user)    { user1.screen_name }
+  let(:target_user)     { user2.screen_name }
+  let(:type)            { nil }
+
+  # test data:
+  let!(:user1) { FactoryBot.create(:user, screen_name: "timallen") }
+  let!(:user2) { FactoryBot.create(:user, screen_name: "joehilyar") }
+
+  subject { described_class.call(params) }
+
+  context "type = 'follow'" do
+    let(:type) { "follow" }
+
+    include_examples "valid relationship type"
+  end
+
+  context "type = 'dick'" do
+    let(:type) { "dick" }
+
+    include_examples "raises an error", Dry::Types::ConstraintError
+  end
+end

spec/lib/use_case/relationship/destroy_spec.rb

@@ -0,0 +1,73 @@
+# frozen_string_literal: true
+
+require "rails_helper"
+
+require "use_case/relationship/destroy"
+require "errors"
+
+describe UseCase::Relationship::Destroy do
+  shared_examples_for "valid relationship type" do
+    its([:status]) { is_expected.to eq(204) }
+    its([:extra])  { is_expected.to eq(target_user: user2) }
+
+    context "relationship exists" do
+      before do
+        user1.public_send(type, user2)
+      end
+
+      it "destroys a relationship" do
+        expect { subject }.to change { Relationship.count }.by(-1)
+      end
+    end
+
+    context "relationship does not exist" do
+      it "does not change anything at all" do
+        expect { subject }.to change { Relationship.count }.by(0)
+      end
+    end
+
+    context "current_user does not exist" do
+      let(:current_user) { "Schweinsbraten" }
+      let(:target_user)     { user2.screen_name }
+
+      include_examples "raises an error", Errors::UserNotFound
+    end
+
+    context "target_user does not exist" do
+      let(:current_user) { user1.screen_name }
+      let(:target_user)     { "peterwitzig" }
+
+      include_examples "raises an error", Errors::UserNotFound
+    end
+  end
+
+  let(:base_params) do
+    {
+      current_user: current_user,
+      target_user:     target_user,
+      type:            type
+    }
+  end
+  let(:params)          { base_params }
+  let(:current_user)    { user1.screen_name }
+  let(:target_user)     { user2.screen_name }
+  let(:type)            { nil }
+
+  # test data:
+  let!(:user1) { FactoryBot.create(:user, screen_name: "timallen") }
+  let!(:user2) { FactoryBot.create(:user, screen_name: "joehilyar") }
+
+  subject { described_class.call(params) }
+
+  context "type = 'follow'" do
+    let(:type) { "follow" }
+
+    include_examples "valid relationship type"
+  end
+
+  context "type = 'dick'" do
+    let(:type) { "dick" }
+
+    include_examples "raises an error", Dry::Types::ConstraintError
+  end
+end

spec/shared_examples/error_raising.rb

@@ -1,5 +1,11 @@
 # frozen_string_literal: true
 
+RSpec.shared_examples_for "raises an error" do |error_klass|
+  it "raises an error" do
+    expect { subject }.to raise_error(kind_of(error_klass))
+  end
+end
+
 RSpec.shared_examples_for "ajax does not succeed" do |part_of_error_message|
   it "ajax does not succeed" do
     subject