UX: Improve error messages for minimum and maximum username lengths.

spec/components/validators/max_username_length_validator_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+describe MaxUsernameLengthValidator do
+  it "checks for minimum range" do
+    SiteSetting.min_username_length = 6
+
+    validator = described_class.new
+    expect(validator.valid_value?(5)).to eq(false)
+    expect(validator.error_message).to eq(I18n.t("site_settings.errors.max_username_length_range"))
+  end
+
+  it "checks for users with short usernames" do
+    user = Fabricate(:user, username: 'jackjackjack')
+
+    validator = described_class.new
+    expect(validator.valid_value?(12)).to eq(true)
+
+    validator = described_class.new
+    expect(validator.valid_value?(11)).to eq(false)
+
+    expect(validator.error_message).to eq(I18n.t(
+      "site_settings.errors.max_username_length_exists",
+      username: 'jackjackjack'
+    ))
+  end
+end

spec/components/validators/min_username_length_validator_spec.rb

@@ -0,0 +1,26 @@
+require 'rails_helper'
+
+describe MinUsernameLengthValidator do
+  it "checks for maximum range" do
+    SiteSetting.max_username_length = 10
+
+    validator = described_class.new
+    expect(validator.valid_value?(11)).to eq(false)
+    expect(validator.error_message).to eq(I18n.t("site_settings.errors.min_username_length_range"))
+  end
+
+  it "checks for users with short usernames" do
+    user = Fabricate(:user, username: 'jack')
+
+    validator = described_class.new
+    expect(validator.valid_value?(4)).to eq(true)
+
+    validator = described_class.new
+    expect(validator.valid_value?(5)).to eq(false)
+
+    expect(validator.error_message).to eq(I18n.t(
+      "site_settings.errors.min_username_length_exists",
+      username: 'jack'
+    ))
+  end
+end