config.load_defaults is now 7.1 and I had to add optional belongs to to a couple models as a deprecation from the 4.2 to 5.0 upgrade

test/models/mat_test.rb

@@ -8,6 +8,6 @@ class MatTest < ActiveSupport::TestCase
    test "Mat validations" do
       mat = Mat.new
       assert_not mat.valid?
-      assert_equal [:name], mat.errors.attribute_names
+      assert_equal [:tournament, :name], mat.errors.attribute_names
     end
 end

test/models/school_test.rb

@@ -8,6 +8,6 @@ class SchoolTest < ActiveSupport::TestCase
    test "School validations" do
       school = School.new
       assert_not school.valid?
-      assert_equal [:name], school.errors.attribute_names
+      assert_equal [:tournament,:name], school.errors.attribute_names
     end
 end

test/models/weight_test.rb

@@ -8,6 +8,6 @@ class WeightTest < ActiveSupport::TestCase
    test "Weight validations" do
       weight = Weight.new
       assert_not weight.valid?
-      assert_equal [:max], weight.errors.attribute_names
+      assert_equal [:tournament, :max], weight.errors.attribute_names
     end
 end

test/models/wrestler_test.rb

@@ -8,6 +8,6 @@ class WrestlerTest < ActiveSupport::TestCase
    test "Wrestler validations" do
       wrestler = Wrestler.new
       assert_not wrestler.valid?
-      assert_equal [:name, :weight_id, :school_id], wrestler.errors.attribute_names
+      assert_equal [:school, :weight, :name, :weight_id, :school_id], wrestler.errors.attribute_names
     end
 end