Add a test for Vault token retrieval retries

When the retryVaultTokenRetrieval option is set in the action
we will now see HTTP errors when retrieving the Vault token retried.

This adds a test block to test the client.post that is performed
during the token retrieval is retried on an HTTP error, like a 500.

src/retries.test.js

@@ -66,4 +66,89 @@ describe('exportSecrets retries', () => {
             done();
         });
     });
-});
+});
+
+describe('exportSecrets retrieve token retries', () => {
+    var server = new ServerMock({ host: "127.0.0.1", port: 0 });
+    var calls = 0;
+
+    beforeEach((done) => {
+        calls = 0;
+        jest.resetAllMocks();
+
+        when(core.getInput)
+            .calledWith('token', expect.anything())
+            .mockReturnValueOnce('EXAMPLE');
+
+        when(core.getInput)
+            .calledWith('secrets', expect.anything())
+            .mockReturnValueOnce("kv/mysecret key");
+
+        when(core.getInput)
+            .calledWith('method', expect.anything())
+            .mockReturnValueOnce('approle')
+
+        when(core.getInput)
+            .calledWith('roleId', expect.anything())
+            .mockReturnValueOnce('roleId')
+
+        when(core.getInput)
+            .calledWith('secretId', expect.anything())
+            .mockReturnValueOnce('secretId')
+
+        when(core.getInput)
+            .calledWith('retryVaultTokenRetrieval', expect.anything())
+            .mockReturnValueOnce('true')
+
+        server.start(() => {
+            expect(server.getHttpPort()).not.toBeNull();
+            when(core.getInput)
+                .calledWith('url', expect.anything())
+                .mockReturnValueOnce('http://127.0.0.1:' + server.getHttpPort());
+            done();
+        });
+    });
+
+    afterEach((done) => {
+        server.stop(done);
+    });
+
+    function mockKvRetrieval() {
+        server.on({
+            path: '/v1/kv/mysecret',
+            reply: {
+                status: 200,
+                headers: { "content-type": "application/json" },
+                body: function() {
+                    return JSON.stringify({ data: {"key": "value"} })
+                }
+            }
+        });
+    }
+
+    function mockStatusCodes(statusCodes) {
+        server.on({
+            method: 'POST',
+            path: '/v1/auth/approle/login',
+            reply: {
+                status: function() {
+                    let status = statusCodes[calls];
+                    calls += 1;
+                    return status;
+                },
+                body: function() {
+                    return JSON.stringify({ auth: {"client_token": "token"} });
+                }
+            }
+        });
+    }
+
+    it('retries on 500 status code', (done) => {
+        mockKvRetrieval()
+        mockStatusCodes([500, 201])
+        exportSecrets().then(() => {
+            expect(calls).toEqual(2);
+            done();
+        });
+    });
+});