test: check provider count

test/integration/client-side-encryption/client_side_encryption.prose.26.custom_aws_credential_providers.test.ts

@@ -60,13 +60,15 @@ describe('25. Custom AWS Credential Providers', metadata, () => {
 
   context('Case 2: Explicit encryption with custom credential provider', metadata, function () {
     let clientEncryption;
+    let providerCount = 0;
 
     beforeEach(function () {
       const options = {
         keyVaultNamespace: 'keyvault.datakeys',
         kmsProviders: { aws: {} },
         credentialProviders: {
           aws: async () => {
+            providerCount++;
             return {
               accessKeyId: process.env.FLE_AWS_KEY,
               secretAccessKey: process.env.FLE_AWS_SECRET
@@ -81,6 +83,7 @@ describe('25. Custom AWS Credential Providers', metadata, () => {
     it('is successful', metadata, async function () {
       const dk = await clientEncryption.createDataKey('aws', { masterKey });
       expect(dk).to.be.instanceOf(Binary);
+      expect(providerCount).to.be.greaterThan(0);
     });
   });