Alerting: Add TestTemplate method to the forked Alertmanager (#77577)

* Alerting: Add an empty Forked Alertmanager

* Alerting: Add methods for silences to the forked Alertmanager

* check for errors in tests

* make linter happy

* Alerting: Add methods for alerts to the forked Alertmanager

* Alerting: Add methods for receivers to the forked Alertmanager

* Alerting: Add TestTemplate method to the forked Alertmanager

* make linter happy

* separate into both forked AMs

* fix tests

pkg/services/ngalert/remote/forked_alertmanager_test.go

@@ -193,6 +193,20 @@ func TestForkedAlertmanager_ModeRemoteSecondary(t *testing.T) {
 		_, err = forked.TestReceivers(ctx, apimodels.TestReceiversConfigBodyParams{})
 		require.ErrorIs(tt, expErr, err)
 	})
+
+	t.Run("TestTemplate", func(tt *testing.T) {
+		// TestTemplate should be called only in the internal Alertmanager.
+		internal, _, forked := genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().TestTemplate(mock.Anything, mock.Anything).Return(nil, nil).Once()
+		_, err := forked.TestTemplate(ctx, apimodels.TestTemplatesConfigBodyParams{})
+		require.NoError(tt, err)
+
+		// If there's an error in the internal Alertmanager, it should be returned.
+		internal, _, forked = genTestAlertmanagers(tt, modeRemoteSecondary)
+		internal.EXPECT().TestTemplate(mock.Anything, mock.Anything).Return(nil, expErr).Once()
+		_, err = forked.TestTemplate(ctx, apimodels.TestTemplatesConfigBodyParams{})
+		require.ErrorIs(tt, expErr, err)
+	})
 }
 
 func TestForkedAlertmanager_ModeRemotePrimary(t *testing.T) {
@@ -368,6 +382,20 @@ func TestForkedAlertmanager_ModeRemotePrimary(t *testing.T) {
 		_, err = forked.TestReceivers(ctx, apimodels.TestReceiversConfigBodyParams{})
 		require.ErrorIs(tt, expErr, err)
 	})
+
+	t.Run("TestTemplate", func(tt *testing.T) {
+		// TestTemplate should be called only in the remote Alertmanager.
+		_, remote, forked := genTestAlertmanagers(tt, modeRemotePrimary)
+		remote.EXPECT().TestTemplate(mock.Anything, mock.Anything).Return(nil, nil).Once()
+		_, err := forked.TestTemplate(ctx, apimodels.TestTemplatesConfigBodyParams{})
+		require.NoError(tt, err)
+
+		// If there's an error in the remote Alertmanager, it should be returned.
+		_, remote, forked = genTestAlertmanagers(tt, modeRemotePrimary)
+		remote.EXPECT().TestTemplate(mock.Anything, mock.Anything).Return(nil, expErr).Once()
+		_, err = forked.TestTemplate(ctx, apimodels.TestTemplatesConfigBodyParams{})
+		require.ErrorIs(tt, expErr, err)
+	})
 }
 func genTestAlertmanagers(t *testing.T, mode int) (*alertmanager_mock.AlertmanagerMock, *alertmanager_mock.AlertmanagerMock, notifier.Alertmanager) {
 	t.Helper()

pkg/services/ngalert/remote/remote_primary_forked_alertmanager.go

@@ -73,7 +73,7 @@ func (fam *RemotePrimaryForkedAlertmanager) TestReceivers(ctx context.Context, c
 }
 
 func (fam *RemotePrimaryForkedAlertmanager) TestTemplate(ctx context.Context, c apimodels.TestTemplatesConfigBodyParams) (*notifier.TestTemplatesResults, error) {
-	return &notifier.TestTemplatesResults{}, nil
+	return fam.remote.TestTemplate(ctx, c)
 }
 
 func (fam *RemotePrimaryForkedAlertmanager) CleanUp() {}

pkg/services/ngalert/remote/remote_secondary_forked_alertmanager.go

@@ -73,7 +73,7 @@ func (fam *RemoteSecondaryForkedAlertmanager) TestReceivers(ctx context.Context,
 }
 
 func (fam *RemoteSecondaryForkedAlertmanager) TestTemplate(ctx context.Context, c apimodels.TestTemplatesConfigBodyParams) (*notifier.TestTemplatesResults, error) {
-	return &notifier.TestTemplatesResults{}, nil
+	return fam.internal.TestTemplate(ctx, c)
 }
 
 func (fam *RemoteSecondaryForkedAlertmanager) CleanUp() {}