Add initial model tests with starter fixtures for User, Family, and Account (#281)

* Add initial user fixture

* Add initial tests for  the User model

* Add initial tests for Family and a valid Account

* Pass rubocop

test/models/family_test.rb

@@ -1,7 +1,28 @@
 require "test_helper"
 
 class FamilyTest < ActiveSupport::TestCase
-  # test "the truth" do
-  #   assert true
-  # end
+  def setup
+    @dylan_family = families(:dylan_family)
+  end
+
+  test "should have many users" do
+    assert_equal 2, @dylan_family.users.size
+    assert @dylan_family.users.include?(users(:bob))
+  end
+
+  test "should have many accounts" do
+    assert_equal 2, @dylan_family.accounts.size
+  end
+
+  test "should destroy dependent users" do
+    assert_difference("User.count", -@dylan_family.users.count) do
+      @dylan_family.destroy
+    end
+  end
+
+  test "should destroy dependent accounts" do
+    assert_difference("Account.count", -@dylan_family.accounts.count) do
+      @dylan_family.destroy
+    end
+  end
 end