Add test case to show that OBO supports SP

Author: rayluo

tests/test_e2e.py

@@ -649,19 +649,27 @@ def _test_acquire_token_obo(self, config_pca, config_cca,
                 # Here we just test regional apps won't adversely break OBO
             http_client=None,
             ):
-        # 1. An app obtains a token representing a user, for our mid-tier service
-        pca = msal.PublicClientApplication(
-            config_pca["client_id"], authority=config_pca["authority"],
-            azure_region=azure_region,
-            http_client=http_client or MinimalHttpClient())
-        pca_result = pca.acquire_token_by_username_password(
-            config_pca["username"],
-            config_pca["password"],
-            scopes=config_pca["scope"],
-            )
-        self.assertIsNotNone(
-            pca_result.get("access_token"),
-            "PCA failed to get AT because %s" % json.dumps(pca_result, indent=2))
+        if "client_secret" not in config_pca:
+            # 1.a An app obtains a token representing a user, for our mid-tier service
+            result = msal.PublicClientApplication(
+                config_pca["client_id"], authority=config_pca["authority"],
+                azure_region=azure_region,
+                http_client=http_client or MinimalHttpClient(),
+                ).acquire_token_by_username_password(
+                    config_pca["username"], config_pca["password"],
+                    scopes=config_pca["scope"],
+                )
+        else:  # We repurpose the config_pca to contain client_secret for cca app 1
+            # 1.b An app obtains a token representing itself, for our mid-tier service
+            result = msal.ConfidentialClientApplication(
+                config_pca["client_id"], authority=config_pca["authority"],
+                client_credential=config_pca["client_secret"],
+                azure_region=azure_region,
+                http_client=http_client or MinimalHttpClient(),
+                ).acquire_token_for_client(scopes=config_pca["scope"])
+        assertion = result.get("access_token")
+        self.assertIsNotNone(assertion, "First app failed to get AT. {}".format(
+            json.dumps(result, indent=2)))
 
         # 2. Our mid-tier service uses OBO to obtain a token for downstream service
         cca = msal.ConfidentialClientApplication(
@@ -674,9 +682,9 @@ def _test_acquire_token_obo(self, config_pca, config_cca,
                 # That's fine if OBO app uses short-lived msal instance per session.
                 # Otherwise, the OBO app need to implement a one-cache-per-user setup.
             )
-        cca_result = cca.acquire_token_on_behalf_of(
-            pca_result['access_token'], config_cca["scope"])
-        self.assertNotEqual(None, cca_result.get("access_token"), str(cca_result))
+        cca_result = cca.acquire_token_on_behalf_of(assertion, config_cca["scope"])
+        self.assertIsNotNone(cca_result.get("access_token"), "OBO call failed: {}".format(
+            json.dumps(cca_result, indent=2)))
 
         # 3. Now the OBO app can simply store downstream token(s) in same session.
         #    Alternatively, if you want to persist the downstream AT, and possibly
@@ -685,13 +693,27 @@ def _test_acquire_token_obo(self, config_pca, config_cca,
         #    Assuming you already did that (which is not shown in this test case),
         #    the following part shows one of the ways to obtain an AT from cache.
         username = cca_result.get("id_token_claims", {}).get("preferred_username")
-        if username:  # It means CCA have requested an IDT w/ "profile" scope
-            self.assertEqual(config_cca["username"], username)
         accounts = cca.get_accounts(username=username)
-        assert len(accounts) == 1, "App is expected to partition token cache per user"
-        account = accounts[0]
+        if username is not None:  # It means CCA have requested an IDT w/ "profile" scope
+            assert config_cca["username"] == username, "Incorrect test case configuration"
+            self.assertEqual(1, len(accounts), "App is supposed to partition token cache per user")
+        account = accounts[0]  # Alternatively, cca app could just loop through each account
         result = cca.acquire_token_silent(config_cca["scope"], account)
-        self.assertEqual(cca_result["access_token"], result["access_token"])
+        self.assertTrue(
+            result and result.get("access_token") == cca_result["access_token"],
+            "CCA should hit an access token from cache: {}".format(
+                json.dumps(cca.token_cache._cache, indent=2)))
+        if "refresh_token" in cca_result:
+            result = cca.acquire_token_silent(
+                config_cca["scope"], account=account, force_refresh=True)
+            self.assertTrue(
+                result and "access_token" in result,
+                "CCA should get an AT silently, but we got this instead: {}".format(result))
+            self.assertNotEqual(
+                result["access_token"], cca_result["access_token"],
+                "CCA should get a new AT")
+        else:
+            logger.info("AAD did not issue a RT for OBO flow")
 
     def _test_acquire_token_by_client_secret(
             self, client_id=None, client_secret=None, authority=None, scope=None,
@@ -933,6 +955,31 @@ def test_acquire_token_obo(self):
 
         self._test_acquire_token_obo(config_pca, config_cca)
 
+    @unittest.skipUnless(
+        os.path.exists("tests/sp_obo.pem"),
+        "Need a 'tests/sp_obo.pem' private to run OBO for SP test")
+    def test_acquire_token_obo_for_sp(self):
+        authority = "https://login.windows-ppe.net/f686d426-8d16-42db-81b7-ab578e110ccd"
+        with open("tests/sp_obo.pem") as pem:
+            client_secret = {
+                "private_key": pem.read(),
+                "thumbprint": "378938210C976692D7F523B8C4FFBB645D17CE92",
+                }
+        midtier_app = {
+            "authority": authority,
+            "client_id": "c84e9c32-0bc9-4a73-af05-9efe9982a322",
+            "client_secret": client_secret,
+            "scope": ["23d08a1e-1249-4f7c-b5a5-cb11f29b6923/.default"],
+            #"username": "OBO-Client-PPE",  # We do NOT attempt locating initial_app by name
+            }
+        initial_app = {
+            "authority": authority,
+            "client_id": "9793041b-9078-4942-b1d2-babdc472cc0c",
+            "client_secret": client_secret,
+            "scope": [midtier_app["client_id"] + "/.default"],
+            }
+        self._test_acquire_token_obo(initial_app, midtier_app)
+
     def test_acquire_token_by_client_secret(self):
         # Vastly different than ArlingtonCloudTestCase.test_acquire_token_by_client_secret()
         _app = self.get_lab_app_object(