From 5c910dc82eb07a0e69e7788280321383405f8196 Mon Sep 17 00:00:00 2001
From: Matt Jankowski <matt@jankowski.online>
Date: Thu, 24 Oct 2024 04:04:29 -0400
Subject: [PATCH] Add coverage for `DatabaseHelper` primary/replica methods
 (#32642)

---
 spec/helpers/database_helper_spec.rb | 61 ++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)
 create mode 100644 spec/helpers/database_helper_spec.rb

diff --git a/spec/helpers/database_helper_spec.rb b/spec/helpers/database_helper_spec.rb
new file mode 100644
index 0000000000..9ea398bf4c
--- /dev/null
+++ b/spec/helpers/database_helper_spec.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe DatabaseHelper do
+  context 'when a replica is enabled' do
+    around do |example|
+      ClimateControl.modify REPLICA_DB_NAME: 'prod-relay-quantum-tunnel-mirror' do
+        example.run
+      end
+    end
+
+    before { allow(ApplicationRecord).to receive(:connected_to) }
+
+    describe '#with_read_replica' do
+      it 'uses the replica for connections' do
+        helper.with_read_replica { _x = 1 }
+
+        expect(ApplicationRecord)
+          .to have_received(:connected_to).with(role: :reading, prevent_writes: true)
+      end
+    end
+
+    describe '#with_primary' do
+      it 'uses the primary for connections' do
+        helper.with_primary { _x = 1 }
+
+        expect(ApplicationRecord)
+          .to have_received(:connected_to).with(role: :writing)
+      end
+    end
+  end
+
+  context 'when a replica is not enabled' do
+    around do |example|
+      ClimateControl.modify REPLICA_DB_NAME: nil do
+        example.run
+      end
+    end
+
+    before { allow(ApplicationRecord).to receive(:connected_to) }
+
+    describe '#with_read_replica' do
+      it 'does not use the replica for connections' do
+        helper.with_read_replica { _x = 1 }
+
+        expect(ApplicationRecord)
+          .to_not have_received(:connected_to).with(role: :reading, prevent_writes: true)
+      end
+    end
+
+    describe '#with_primary' do
+      it 'does not use the primary for connections' do
+        helper.with_primary { _x = 1 }
+
+        expect(ApplicationRecord)
+          .to_not have_received(:connected_to).with(role: :writing)
+      end
+    end
+  end
+end