clean up AwsIamStrategy tests

Make it easier to stub and check the presign mock.

Signed-off-by: Jamie Klassen <jamie.klassen@broadcom.com>

plugins/kubernetes-backend/src/auth/AwsIamStrategy.test.ts

@@ -20,12 +20,6 @@ import {
 } from '@backstage/plugin-kubernetes-common';
 import { AwsIamStrategy } from './AwsIamStrategy';
 
-let presign = jest.fn(async () => ({
-  hostname: 'https://example.com',
-  query: {},
-  path: '/asdf',
-}));
-
 const credsManager = {
   getCredentialProvider: async () => ({
     sdkCredentialProvider: {
@@ -40,12 +34,16 @@ jest.mock('@backstage/integration-aws-node', () => ({
   },
 }));
 
-const config = new ConfigReader({});
+const signer = {
+  presign: jest.fn().mockResolvedValue({
+    hostname: 'https://example.com',
+    query: {},
+    path: '/asdf',
+  }),
+};
 
 jest.mock('@aws-sdk/signature-v4', () => ({
-  SignatureV4: jest.fn().mockImplementation(() => ({
-    presign,
-  })),
+  SignatureV4: jest.fn().mockImplementation(() => signer),
 }));
 
 const fromTemporaryCredentials = jest.fn();
@@ -55,9 +53,10 @@ jest.mock('@aws-sdk/credential-providers', () => ({
   },
 }));
 
-describe('AwsIamStrategy tests', () => {
-  beforeEach(() => {});
-  it('returns a signed url for AWS credentials without assume role', async () => {
+describe('AwsIamStrategy#getCredential', () => {
+  const config = new ConfigReader({});
+
+  it('returns a presigned url for cluster name', async () => {
     const strategy = new AwsIamStrategy({ config });
 
     const credential = await strategy.getCredential({
@@ -65,10 +64,17 @@ describe('AwsIamStrategy tests', () => {
       url: '',
       authMetadata: {},
     });
+
     expect(credential).toEqual({
       type: 'bearer token',
       token: 'k8s-aws-v1.aHR0cHM6Ly9odHRwczovL2V4YW1wbGUuY29tL2FzZGY_',
     });
+    expect(signer.presign).toHaveBeenCalledWith(
+      expect.objectContaining({
+        headers: expect.objectContaining({ 'x-k8s-aws-id': 'test-cluster' }),
+      }),
+      expect.anything(),
+    );
   });
 
   it('returns a signed url for AWS credentials with assume role', async () => {
@@ -129,21 +135,17 @@ describe('AwsIamStrategy tests', () => {
     });
   });
 
-  describe('When the credentials is failing', () => {
-    beforeEach(() => {
-      presign = jest.fn(async () => {
-        throw new Error('no way');
-      });
-    });
-    it('throws the right error', async () => {
-      const strategy = new AwsIamStrategy({ config });
-      await expect(
-        strategy.getCredential({
-          name: 'test-cluster',
-          url: '',
-          authMetadata: {},
-        }),
-      ).rejects.toThrow('no way');
-    });
+  it('fails on signer error', () => {
+    signer.presign.mockRejectedValue(new Error('no way'));
+
+    const strategy = new AwsIamStrategy({ config });
+
+    return expect(
+      strategy.getCredential({
+        name: 'test-cluster',
+        url: '',
+        authMetadata: {},
+      }),
+    ).rejects.toThrow('no way');
   });
 });