1 files changed, 51 insertions, 0 deletions
diff --git a/spec/lib/gitlab/usage/metrics/query_spec.rb b/spec/lib/gitlab/usage/metrics/query_spec.rb
new file mode 100644
index 00000000000..60c8d044a64
--- /dev/null
+++ b/spec/lib/gitlab/usage/metrics/query_spec.rb
@@ -0,0 +1,51 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Usage::Metrics::Query do
+  describe '.count' do
+    it 'returns the raw SQL' do
+      expect(described_class.for(:count, User)).to eq('SELECT COUNT("users"."id") FROM "users"')
+    end
+
+    it 'does not mix a nil column with keyword arguments' do
+      expect(described_class.for(:count, User, nil)).to eq('SELECT COUNT("users"."id") FROM "users"')
+    end
+  end
+
+  describe '.distinct_count' do
+    it 'returns the raw SQL' do
+      expect(described_class.for(:distinct_count, Issue, :author_id)).to eq('SELECT COUNT(DISTINCT "issues"."author_id") FROM "issues"')
+    end
+
+    it 'does not mix a nil column with keyword arguments' do
+      expect(described_class.for(:distinct_count, Issue, nil)).to eq('SELECT COUNT(DISTINCT "issues"."id") FROM "issues"')
+    end
+  end
+
+  describe '.sum' do
+    it 'returns the raw SQL' do
+      expect(described_class.for(:sum, Issue, :weight)).to eq('SELECT SUM("issues"."weight") FROM "issues"')
+    end
+  end
+
+  describe 'estimate_batch_distinct_count' do
+    it 'returns the raw SQL' do
+      expect(described_class.for(:estimate_batch_distinct_count, Issue, :author_id)).to eq('SELECT COUNT(DISTINCT "issues"."author_id") FROM "issues"')
+    end
+  end
+
+  describe '.histogram' do
+    it 'returns the histogram sql' do
+      expect(described_class.for(:histogram, AlertManagement::HttpIntegration.active,
+            :project_id, buckets: 1..2, bucket_size: 101))
+        .to match(/^WITH "count_cte" AS #{Gitlab::Database::AsWithMaterialized.materialized_if_supported}/)
+    end
+  end
+
+  describe 'other' do
+    it 'raise ArgumentError error' do
+      expect { described_class.for(:other, nil) }.to raise_error(ArgumentError, 'other operation not supported')
+    end
+  end
+end