Account namespace updates: part 4 (transfers, singular namespacing) (#896)

* Move Transfer to Account namespace

* Fix partial resolution due to namespacing plurality

* Make category and tag controllers consistent with namespacing convention

* Update stale partial reference

test/system/transfers_test.rb

@@ -0,0 +1,82 @@
+require "application_system_test_case"
+
+class TransfersTest < ApplicationSystemTestCase
+  setup do
+    sign_in @user = users(:family_admin)
+    visit transactions_url
+  end
+
+  test "can create a transfer" do
+    checking_name = accounts(:checking).name
+    savings_name = accounts(:savings).name
+    transfer_date = Date.current
+
+    click_on "New transaction"
+
+    # Will navigate to different route in same modal
+    click_on "Transfer"
+    assert_text "New transfer"
+
+    fill_in "Description", with: "Transfer txn name"
+    select checking_name, from: "From"
+    select savings_name, from: "To"
+    fill_in "account_transfer[amount]", with: 500
+    fill_in "Date", with: transfer_date
+    click_button "Create transfer"
+
+    within "#date-group-" + transfer_date.to_s do
+      transfer_name = "Transfer from #{checking_name} to #{savings_name}"
+      find("details", text: transfer_name).click
+      assert_text "Transfer txn name", count: 2
+    end
+  end
+
+  test "can match 2 transactions and create a transfer" do
+    transfer_date = Date.current
+    outflow = Transaction.create! name: "Outflow from savings account", date: transfer_date, account: accounts(:savings), amount: 100
+    inflow = Transaction.create! name: "Inflow to checking account", date: transfer_date, account: accounts(:checking), amount: -100
+
+    visit transactions_url
+
+    transaction_checkbox(inflow).check
+    transaction_checkbox(outflow).check
+
+    bulk_transfer_action_button.click
+
+    click_on "Mark as transfers"
+
+    within "#date-group-" + transfer_date.to_s do
+      transfer_name = "Transfer from #{outflow.account.name} to #{inflow.account.name}"
+      find("details", text: transfer_name).click
+      assert_text inflow.name
+      assert_text outflow.name
+    end
+  end
+
+  test "can mark a single transaction as a transfer" do
+    txn = @user.family.transactions.ordered.first
+
+    within "#" + dom_id(txn) do
+      assert_text "Uncategorized"
+    end
+
+    transaction_checkbox(txn).check
+
+    bulk_transfer_action_button.click
+    click_on "Mark as transfers"
+
+    within "#" + dom_id(txn) do
+      assert_no_text "Uncategorized"
+    end
+  end
+
+  private
+
+    def transaction_checkbox(transaction)
+      find("#" + dom_id(transaction, "selection"))
+    end
+
+    def bulk_transfer_action_button
+      find("#bulk-transfer-btn")
+    end
+end