Include CI Variable Key in its uniqueness validation error message

app/models/ci/group_variable.rb

@@ -6,7 +6,10 @@ module Ci
     belongs_to :group
-    validates :key, uniqueness: { scope: :group_id }
+    validates :key, uniqueness: {
+      scope: :group_id,
+      message: "(%{value}) has already been taken"
+    }
     scope :unprotected, -> { where(protected: false) }
   end

app/models/ci/variable.rb

@@ -6,7 +6,10 @@ module Ci
     belongs_to :project
-    validates :key, uniqueness: { scope: [:project_id, :environment_scope] }
+    validates :key, uniqueness: {
+      scope: [:project_id, :environment_scope],
+      message: "(%{value}) has already been taken"
+    }
     scope :unprotected, -> { where(protected: false) }
   end

spec/models/ci/group_variable_spec.rb

@@ -5,7 +5,7 @@ describe Ci::GroupVariable do
   it { is_expected.to include_module(HasVariable) }
   it { is_expected.to include_module(Presentable) }
-  it { is_expected.to validate_uniqueness_of(:key).scoped_to(:group_id) }
+  it { is_expected.to validate_uniqueness_of(:key).scoped_to(:group_id).with_message(/\(\w+\) has already been taken/) }
   describe '.unprotected' do
     subject { described_class.unprotected }

spec/models/ci/variable_spec.rb

@@ -6,7 +6,7 @@ describe Ci::Variable do
   describe 'validations' do
     it { is_expected.to include_module(HasVariable) }
     it { is_expected.to include_module(Presentable) }
-    it { is_expected.to validate_uniqueness_of(:key).scoped_to(:project_id, :environment_scope) }
+    it { is_expected.to validate_uniqueness_of(:key).scoped_to(:project_id, :environment_scope).with_message(/\(\w+\) has already been taken/) }
   end
   describe '.unprotected' do