add tests for retries

Signed-off-by: Fedor Dikarev <fedor.dikarev@gmail.com>

__tests__/retries.test.ts

@@ -0,0 +1,37 @@
+import { expect, jest, test, } from '@jest/globals';
+import * as path from 'path';
+
+// import * as dockerModule from '../src/docker';
+
+import { login } from '../src/docker';
+import { Docker } from '@docker/actions-toolkit/lib/docker/docker';
+
+test('login retries function', async () => {
+  const stderr_strings = [
+    'mock error, failed with status: 408 Request Timeout',
+    'mock error, failed with status: 502 Request Timeout',
+    'mock error, failed with status: 400 Request Timeout',
+  ]
+  let call_count: number = 0
+
+  Docker.getExecOutput = jest.fn(async () => {
+    if (call_count >= stderr_strings.length) {
+      return {
+        exitCode: 0,
+        stdout: 'Mock success',
+        stderr: ''
+      }
+    }
+    return {
+      exitCode: 1,
+      stdout: '',
+      stderr: stderr_strings[(call_count++) % stderr_strings.length]
+    }
+  })
+
+  const username = 'dbowie';
+  const password = 'groundcontrol';
+  const registry = 'https://ghcr.io';
+
+  await login(registry, username, password, 'false', ['408', '502', '400'], 5, 0.5);
+});