Add new check 'busy' bill runs service

app/services/bill-runs/check-busy-bill-runs.service.js

@@ -0,0 +1,47 @@
+'use strict'
+
+/**
+ * Check if any bill runs are being processed or cancelled
+ * @module CheckBusyBillRunsService
+ */
+
+const { db } = require('../../../db/db.js')
+
+/**
+ * Check if any bill runs are busy building or cancelling
+ *
+ * A bill run is 'cancelling' if its status is `cancel`. A bill run is 'building' if its status is `processing`,
+ * `queued`, or `sending`.
+ *
+ * @returns {Promise<string>} the state of busy bill runs; 'cancelling', 'building', 'both', or 'none'
+ */
+async function go () {
+  const { building, cancelling } = await _fetch()
+
+  if (building && cancelling) {
+    return 'both'
+  }
+
+  if (building) {
+    return 'building'
+  }
+
+  if (cancelling) {
+    return 'cancelling'
+  }
+
+  return 'none'
+}
+
+async function _fetch () {
+  const results = await db.select(
+    db.raw("EXISTS(SELECT 1 FROM public.bill_runs bb WHERE bb.status = 'cancel') AS cancelling"),
+    db.raw("EXISTS(SELECT 1 FROM public.bill_runs bb WHERE bb.status IN ('processing', 'queued', 'sending')) AS building")
+  )
+
+  return results[0]
+}
+
+module.exports = {
+  go
+}

test/services/bill-runs/check-busy-bill-runs.service.test.js

@@ -0,0 +1,96 @@
+'use strict'
+
+// Test framework dependencies
+const Lab = require('@hapi/lab')
+const Code = require('@hapi/code')
+
+const { describe, it, beforeEach } = exports.lab = Lab.script()
+const { expect } = Code
+
+// Test helpers
+const BillRunHelper = require('../../support/helpers/bill-run.helper.js')
+const DatabaseSupport = require('../../support/database.js')
+
+// Thing under test
+const CheckBusyBillRunsService = require('../../../app/services/bill-runs/check-busy-bill-runs.service.js')
+
+describe('Check Busy Bill Runs service', () => {
+  beforeEach(async () => {
+    await DatabaseSupport.clean()
+
+    // We always add a bill run that is not 'busy' to confirm the service is differentiating between 'busy' and
+    // 'not busy'.
+    await BillRunHelper.add({ status: 'ready' })
+  })
+
+  describe('when there are both building and cancelling bill runs', () => {
+    beforeEach(async () => {
+      await BillRunHelper.add({ status: 'cancel' })
+      await BillRunHelper.add({ status: 'processing' })
+    })
+
+    it("returns 'both'", async () => {
+      const result = await CheckBusyBillRunsService.go()
+
+      expect(result).to.equal('both')
+    })
+  })
+
+  describe('when there are cancelling bill runs', () => {
+    beforeEach(async () => {
+      await BillRunHelper.add({ status: 'cancel' })
+    })
+
+    it("returns 'cancelling'", async () => {
+      const result = await CheckBusyBillRunsService.go()
+
+      expect(result).to.equal('cancelling')
+    })
+  })
+
+  describe('when there are building bill runs', () => {
+    describe("because their status is 'processing'", () => {
+      beforeEach(async () => {
+        await BillRunHelper.add({ status: 'processing' })
+      })
+
+      it("returns 'building'", async () => {
+        const result = await CheckBusyBillRunsService.go()
+
+        expect(result).to.equal('building')
+      })
+    })
+
+    describe("because their status is 'queued'", () => {
+      beforeEach(async () => {
+        await BillRunHelper.add({ status: 'queued' })
+      })
+
+      it("returns 'building'", async () => {
+        const result = await CheckBusyBillRunsService.go()
+
+        expect(result).to.equal('building')
+      })
+    })
+
+    describe("because their status is 'sending'", () => {
+      beforeEach(async () => {
+        await BillRunHelper.add({ status: 'sending' })
+      })
+
+      it("returns 'building'", async () => {
+        const result = await CheckBusyBillRunsService.go()
+
+        expect(result).to.equal('building')
+      })
+    })
+  })
+
+  describe('when there are no building or cancelling bill runs', () => {
+    it("returns 'none'", async () => {
+      const result = await CheckBusyBillRunsService.go()
+
+      expect(result).to.equal('none')
+    })
+  })
+})