1 files changed, 116 insertions, 0 deletions
diff --git a/spec/lib/gitlab/database/postgres_index_spec.rb b/spec/lib/gitlab/database/postgres_index_spec.rb
new file mode 100644
index 00000000000..1da67a5a6c0
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+++ b/spec/lib/gitlab/database/postgres_index_spec.rb
@@ -0,0 +1,116 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Database::PostgresIndex do
+  before do
+    ActiveRecord::Base.connection.execute(<<~SQL)
+      CREATE INDEX foo_idx ON public.users (name);
+      CREATE UNIQUE INDEX bar_key ON public.users (id);
+
+      CREATE TABLE example_table (id serial primary key);
+    SQL
+  end
+
+  def find(name)
+    described_class.by_identifier(name)
+  end
+
+  describe '.by_identifier' do
+    it 'finds the index' do
+      expect(find('public.foo_idx')).to be_a(Gitlab::Database::PostgresIndex)
+    end
+
+    it 'raises an error if not found' do
+      expect { find('public.idontexist') }.to raise_error(ActiveRecord::RecordNotFound)
+    end
+
+    it 'raises ArgumentError if given a non-fully qualified index name' do
+      expect { find('foo') }.to raise_error(ArgumentError, /not fully qualified/)
+    end
+  end
+
+  describe '.regular' do
+    it 'only non-unique indexes' do
+      expect(described_class.regular).to all(have_attributes(unique: false))
+    end
+
+    it 'only non partitioned indexes ' do
+      expect(described_class.regular).to all(have_attributes(partitioned: false))
+    end
+
+    it 'only indexes that dont serve an exclusion constraint' do
+      expect(described_class.regular).to all(have_attributes(exclusion: false))
+    end
+  end
+
+  describe '.not_match' do
+    it 'excludes indexes matching the given regex' do
+      expect(described_class.not_match('^bar_k').map(&:name)).to all(match(/^(?!bar_k).*/))
+    end
+
+    it 'matches indexes without this prefix regex' do
+      expect(described_class.not_match('^bar_k')).not_to be_empty
+    end
+  end
+
+  describe '.random_few' do
+    it 'limits to two records by default' do
+      expect(described_class.random_few(2).size).to eq(2)
+    end
+  end
+
+  describe '#unique?' do
+    it 'returns true for a unique index' do
+      expect(find('public.bar_key')).to be_unique
+    end
+
+    it 'returns false for a regular, non-unique index' do
+      expect(find('public.foo_idx')).not_to be_unique
+    end
+
+    it 'returns true for a primary key index' do
+      expect(find('public.example_table_pkey')).to be_unique
+    end
+  end
+
+  describe '#valid_index?' do
+    it 'returns true if the index is invalid' do
+      expect(find('public.foo_idx')).to be_valid_index
+    end
+
+    it 'returns false if the index is marked as invalid' do
+      ActiveRecord::Base.connection.execute(<<~SQL)
+        UPDATE pg_index SET indisvalid=false
+        FROM pg_class
+        WHERE pg_class.relname = 'foo_idx' AND pg_index.indexrelid = pg_class.oid
+      SQL
+
+      expect(find('public.foo_idx')).not_to be_valid_index
+    end
+  end
+
+  describe '#to_s' do
+    it 'returns the index name' do
+      expect(find('public.foo_idx').to_s).to eq('foo_idx')
+    end
+  end
+
+  describe '#name' do
+    it 'returns the name' do
+      expect(find('public.foo_idx').name).to eq('foo_idx')
+    end
+  end
+
+  describe '#schema' do
+    it 'returns the index schema' do
+      expect(find('public.foo_idx').schema).to eq('public')
+    end
+  end
+
+  describe '#definition' do
+    it 'returns the index definition' do
+      expect(find('public.foo_idx').definition).to eq('CREATE INDEX foo_idx ON public.users USING btree (name)')
+    end
+  end
+end