Add unit test for KerberosCredentialsManager

First batch of KerberosCredentialsManager unit tests. Also adds a test
interface to FakeKerberosClient to
- Set the task delay (tests set it to 0 to speed up the tests),
- Record which functions are called for testing.

BUG=chromium:952251
TEST=Unit tests succeed

Change-Id: I14b3790d1dfb9809e0bc6b7b59a9b58d196e1929
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1760951
Commit-Queue: Lutz Justen <ljusten@chromium.org>
Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Reviewed-by: Lutz Justen <ljusten@chromium.org>
Auto-Submit: Lutz Justen <ljusten@chromium.org>
Cr-Commit-Position: refs/heads/master@{#693140}

chrome/browser/chromeos/BUILD.gn

@@ -2580,6 +2580,7 @@ source_set("unit_tests") {
     "input_method/input_method_engine_unittest.cc",
     "input_method/input_method_manager_impl_unittest.cc",
     "input_method/input_method_persistence_unittest.cc",
+    "kerberos/kerberos_credentials_manager_test.cc",
     "kerberos/kerberos_ticket_expiry_notification_test.cc",
     "locale_change_guard_unittest.cc",
     "lock_screen_apps/app_manager_impl_unittest.cc",

chrome/browser/chromeos/kerberos/kerberos_credentials_manager.cc

@@ -741,7 +741,7 @@ void KerberosCredentialsManager::DoValidateActivePrincipal(
     found |= response.accounts(n).principal_name() == active_principal;
 
   if (!found) {
-    LOG(ERROR) << "Active principal got removed. Restoring.";
+    VLOG(1) << "Active principal got removed. Restoring.";
     if (response.accounts_size() > 0)
       SetActivePrincipalName(response.accounts(0).principal_name());
     else
@@ -803,8 +803,8 @@ void KerberosCredentialsManager::UpdateAccountsFromPref() {
     NotifyRequiresLoginPassword(false);
 
     // https://crbug.com/963824: The active principal is empty if there are no
-    // accounts, so no need to remove accounts. It would just up the daemon
-    // unnecessarily.
+    // accounts, so no need to remove accounts. It would just start up the
+    // daemon unnecessarily.
     if (!GetActivePrincipalName().empty())
       RemoveAllManagedAccountsExcept({});
     return;

chromeos/dbus/kerberos/fake_kerberos_client.h

@@ -10,6 +10,7 @@
 #include <unordered_set>
 #include <vector>
 
+#include "base/optional.h"
 #include "chromeos/dbus/kerberos/kerberos_client.h"
 #include "chromeos/dbus/kerberos/kerberos_service.pb.h"
 #include "dbus/object_proxy.h"
@@ -17,7 +18,8 @@
 namespace chromeos {
 
 class COMPONENT_EXPORT(CHROMEOS_DBUS) FakeKerberosClient
-    : public KerberosClient {
+    : public KerberosClient,
+      public KerberosClient::TestInterface {
  public:
   FakeKerberosClient();
   ~FakeKerberosClient() override;
@@ -44,6 +46,12 @@ class COMPONENT_EXPORT(CHROMEOS_DBUS) FakeKerberosClient
       KerberosFilesChangedCallback callback) override;
   void ConnectToKerberosTicketExpiringSignal(
       KerberosTicketExpiringCallback callback) override;
+  KerberosClient::TestInterface* GetTestInterface() override;
+
+  // KerberosClient::TestInterface:
+  void SetTaskDelay(base::TimeDelta delay) override;
+  void StartRecordingFunctionCalls() override;
+  std::string StopRecordingAndGetRecordedFunctionCalls() override;
 
  private:
   struct AccountData {
@@ -83,9 +91,18 @@ class COMPONENT_EXPORT(CHROMEOS_DBUS) FakeKerberosClient
   // otherwise.
   AccountData* GetAccountData(const std::string& principal_name);
 
+  // Appends |function_name| to |recorded_function_calls_| if the latter is set.
+  void MaybeRecordFunctionCallForTesting(const char* function_name);
+
   // Maps principal name (user@REALM.COM) to account data.
   std::vector<AccountData> accounts_;
 
+  // For recording which methods have been called (for testing).
+  base::Optional<std::string> recorded_function_calls_;
+
+  // Fake delay for any asynchronous operation.
+  base::TimeDelta mTaskDelay = base::TimeDelta::FromMilliseconds(100);
+
   KerberosFilesChangedCallback kerberos_files_changed_callback_;
   KerberosTicketExpiringCallback kerberos_ticket_expiring_callback_;
 

chromeos/dbus/kerberos/kerberos_client.cc

@@ -170,6 +170,8 @@ class KerberosClientImpl : public KerberosClient {
   }
 
  private:
+  TestInterface* GetTestInterface() override { return nullptr; }
+
   // Calls kerberosd's |method_name| method, passing in |request| as input. Once
   // the (asynchronous) call finishes, |callback| is called with the response
   // proto (on the same thread as this call).

chromeos/dbus/kerberos/kerberos_client.h

@@ -43,6 +43,25 @@ class COMPONENT_EXPORT(KERBEROS) KerberosClient {
   using KerberosTicketExpiringCallback =
       base::RepeatingCallback<void(const std::string& principal_name)>;
 
+  // Interface with testing functionality. Accessed through GetTestInterface(),
+  // only implemented in the fake implementation.
+  class TestInterface {
+   public:
+    // Sets the artificial delay for asynchronous function calls.
+    // Should be set to 0 for tests.
+    virtual void SetTaskDelay(base::TimeDelta delay) = 0;
+
+    // Starts recording which functions are called.
+    virtual void StartRecordingFunctionCalls() = 0;
+
+    // Stops recording which functions are called and returns calls as a
+    // comma separated list, e.g. "AddAccount,ListAccounts".
+    virtual std::string StopRecordingAndGetRecordedFunctionCalls() = 0;
+
+   protected:
+    virtual ~TestInterface() {}
+  };
+
   // Creates and initializes the global instance. |bus| must not be null.
   static void Initialize(dbus::Bus* bus);
 
@@ -91,6 +110,9 @@ class COMPONENT_EXPORT(KERBEROS) KerberosClient {
   virtual void ConnectToKerberosTicketExpiringSignal(
       KerberosTicketExpiringCallback callback) = 0;
 
+  // Returns an interface for testing (fake only), or returns nullptr.
+  virtual TestInterface* GetTestInterface() = 0;
+
  protected:
   // Initialize/Shutdown should be used instead.
   KerberosClient();