Add PM2 deployment support

tests/environment.test.ts

@@ -0,0 +1,59 @@
+import { mkdtempSync, rmSync, writeFileSync } from 'node:fs'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { afterEach, describe, expect, it } from 'vitest'
+import { loadEnvironmentFile } from '../src/server/environment.js'
+
+const testVariable = 'PRODUCT_ISSUE_ENV_FILE_TEST'
+const originalValue = process.env[testVariable]
+const temporaryDirectories: string[] = []
+
+afterEach(() => {
+  if (originalValue === undefined) {
+    delete process.env[testVariable]
+  } else {
+    process.env[testVariable] = originalValue
+  }
+  for (const directory of temporaryDirectories.splice(0)) {
+    rmSync(directory, { recursive: true, force: true })
+  }
+})
+
+function environmentFile(value: string): string {
+  const directory = mkdtempSync(join(tmpdir(), 'product-issue-env-'))
+  temporaryDirectories.push(directory)
+  const filePath = join(directory, '.env')
+  writeFileSync(filePath, `${testVariable}=${value}\n`, {
+    encoding: 'utf8',
+    mode: 0o600
+  })
+  return filePath
+}
+
+describe('loadEnvironmentFile', () => {
+  it('loads values from an explicit environment file', () => {
+    delete process.env[testVariable]
+
+    const filePath = environmentFile('from-file')
+
+    expect(loadEnvironmentFile(filePath)).toBe(filePath)
+    expect(process.env[testVariable]).toBe('from-file')
+  })
+
+  it('does not override values already provided by the process', () => {
+    process.env[testVariable] = 'from-process'
+
+    loadEnvironmentFile(environmentFile('from-file'))
+
+    expect(process.env[testVariable]).toBe('from-process')
+  })
+
+  it('fails when an explicitly configured file does not exist', () => {
+    const directory = mkdtempSync(join(tmpdir(), 'product-issue-env-'))
+    temporaryDirectories.push(directory)
+
+    expect(() => loadEnvironmentFile(join(directory, '.env'))).toThrow(
+      'Environment file does not exist'
+    )
+  })
+})