transition api methods to interfaces (#2010)

## Description

replaces the new api client methods with interfaces, to prepare for testing funcions with mocks instead of integration.

## Does this PR need a docs update or release note?

- [x] ⛔ No 

## Type of change

- [x] 🤖 Test

## Issue(s)

* #1967

## Test Plan

- [x] ⚡ Unit test
- [x] 💚 E2E

src/internal/connector/exchange/api/api.go

@@ -87,6 +87,18 @@ func newService(creds account.M365Config) (*graph.Service, error) {
 	return graph.NewService(adapter), nil
 }
 
+func (c Client) Contacts() Contacts {
+	return Contacts{c}
+}
+
+func (c Client) Events() Events {
+	return Events{c}
+}
+
+func (c Client) Mail() Mail {
+	return Mail{c}
+}
+
 // ---------------------------------------------------------------------------
 // helper funcs
 // ---------------------------------------------------------------------------

src/internal/connector/exchange/api/api_test.go

@@ -174,11 +174,11 @@ func (suite *ExchangeServiceSuite) TestGraphQueryFunctions() {
 	}{
 		{
 			name:     "GraphQuery: Get All ContactFolders",
-			function: c.GetAllContactFolderNamesForUser,
+			function: c.Contacts().GetAllContactFolderNamesForUser,
 		},
 		{
 			name:     "GraphQuery: Get All Calendars for User",
-			function: c.GetAllCalendarNamesForUser,
+			function: c.Events().GetAllCalendarNamesForUser,
 		},
 	}
 

src/internal/connector/exchange/api/contacts.go

@@ -13,9 +13,21 @@ import (
 	"github.com/alcionai/corso/src/internal/connector/support"
 )
 
+// ---------------------------------------------------------------------------
+// controller
+// ---------------------------------------------------------------------------
+
+type Contacts struct {
+	Client
+}
+
+// ---------------------------------------------------------------------------
+// methods
+// ---------------------------------------------------------------------------
+
 // CreateContactFolder makes a contact folder with the displayName of folderName.
 // If successful, returns the created folder object.
-func (c Client) CreateContactFolder(
+func (c Contacts) CreateContactFolder(
 	ctx context.Context,
 	user, folderName string,
 ) (models.ContactFolderable, error) {
@@ -28,7 +40,7 @@ func (c Client) CreateContactFolder(
 
 // DeleteContactFolder deletes the ContactFolder associated with the M365 ID if permissions are valid.
 // Errors returned if the function call was not successful.
-func (c Client) DeleteContactFolder(
+func (c Contacts) DeleteContactFolder(
 	ctx context.Context,
 	user, folderID string,
 ) error {
@@ -36,7 +48,7 @@ func (c Client) DeleteContactFolder(
 }
 
 // RetrieveContactDataForUser is a GraphRetrievalFun that returns all associated fields.
-func (c Client) RetrieveContactDataForUser(
+func (c Contacts) RetrieveContactDataForUser(
 	ctx context.Context,
 	user, m365ID string,
 ) (serialization.Parsable, error) {
@@ -46,7 +58,7 @@ func (c Client) RetrieveContactDataForUser(
 // GetAllContactFolderNamesForUser is a GraphQuery function for getting
 // ContactFolderId and display names for contacts. All other information is omitted.
 // Does not return the default Contact Folder
-func (c Client) GetAllContactFolderNamesForUser(
+func (c Contacts) GetAllContactFolderNamesForUser(
 	ctx context.Context,
 	user string,
 ) (serialization.Parsable, error) {
@@ -58,16 +70,13 @@ func (c Client) GetAllContactFolderNamesForUser(
 	return c.stable.Client().UsersById(user).ContactFolders().Get(ctx, options)
 }
 
-func (c Client) GetContactFolderByID(
+func (c Contacts) GetContainerByID(
 	ctx context.Context,
 	userID, dirID string,
-	optionalFields ...string,
-) (models.ContactFolderable, error) {
-	fields := append([]string{"displayName", "parentFolderId"}, optionalFields...)
-
-	ofcf, err := optionsForContactFolderByID(fields)
+) (graph.Container, error) {
+	ofcf, err := optionsForContactFolderByID([]string{"displayName", "parentFolderId"})
 	if err != nil {
-		return nil, errors.Wrapf(err, "options for contact folder: %v", fields)
+		return nil, errors.Wrap(err, "options for contact folder")
 	}
 
 	return c.stable.Client().
@@ -76,13 +85,13 @@ func (c Client) GetContactFolderByID(
 		Get(ctx, ofcf)
 }
 
-// EnumerateContactsFolders iterates through all of the users current
+// EnumerateContainers iterates through all of the users current
 // contacts folders, converting each to a graph.CacheFolder, and calling
 // fn(cf) on each one.  If fn(cf) errors, the error is aggregated
 // into a multierror that gets returned to the caller.
 // Folder hierarchy is represented in its current state, and does
 // not contain historical data.
-func (c Client) EnumerateContactsFolders(
+func (c Contacts) EnumerateContainers(
 	ctx context.Context,
 	userID, baseDirID string,
 	fn func(graph.CacheFolder) error,
@@ -138,9 +147,7 @@ func (c Client) EnumerateContactsFolders(
 	return errs.ErrorOrNil()
 }
 
-// FetchContactIDsFromDirectory function that returns a list of  all the m365IDs of the contacts
-// of the targeted directory
-func (c Client) FetchContactIDsFromDirectory(
+func (c Contacts) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, directoryID, oldDelta string,
 ) ([]string, []string, DeltaUpdate, error) {

src/internal/connector/exchange/api/events.go

@@ -14,9 +14,21 @@ import (
 	"github.com/alcionai/corso/src/pkg/path"
 )
 
+// ---------------------------------------------------------------------------
+// controller
+// ---------------------------------------------------------------------------
+
+type Events struct {
+	Client
+}
+
+// ---------------------------------------------------------------------------
+// methods
+// ---------------------------------------------------------------------------
+
 // CreateCalendar makes an event Calendar with the name in the user's M365 exchange account
 // Reference: https://docs.microsoft.com/en-us/graph/api/user-post-calendars?view=graph-rest-1.0&tabs=go
-func (c Client) CreateCalendar(
+func (c Events) CreateCalendar(
 	ctx context.Context,
 	user, calendarName string,
 ) (models.Calendarable, error) {
@@ -28,7 +40,7 @@ func (c Client) CreateCalendar(
 
 // DeleteCalendar removes calendar from user's M365 account
 // Reference: https://docs.microsoft.com/en-us/graph/api/calendar-delete?view=graph-rest-1.0&tabs=go
-func (c Client) DeleteCalendar(
+func (c Events) DeleteCalendar(
 	ctx context.Context,
 	user, calendarID string,
 ) error {
@@ -36,7 +48,7 @@ func (c Client) DeleteCalendar(
 }
 
 // RetrieveEventDataForUser is a GraphRetrievalFunc that returns event data.
-func (c Client) RetrieveEventDataForUser(
+func (c Events) RetrieveEventDataForUser(
 	ctx context.Context,
 	user, m365ID string,
 ) (serialization.Parsable, error) {
@@ -55,15 +67,15 @@ func (c Client) GetAllCalendarNamesForUser(
 	return c.stable.Client().UsersById(user).Calendars().Get(ctx, options)
 }
 
-// EnumerateCalendars iterates through all of the users current
-// contacts folders, converting each to a graph.CacheFolder, and
+// EnumerateContainers iterates through all of the users current
+// calendars, converting each to a graph.CacheFolder, and
 // calling fn(cf) on each one.  If fn(cf) errors, the error is
 // aggregated into a multierror that gets returned to the caller.
 // Folder hierarchy is represented in its current state, and does
 // not contain historical data.
-func (c Client) EnumerateCalendars(
+func (c Events) EnumerateContainers(
 	ctx context.Context,
-	userID string,
+	userID, baseDirID string,
 	fn func(graph.CacheFolder) error,
 ) error {
 	service, err := c.service()
@@ -112,8 +124,7 @@ func (c Client) EnumerateCalendars(
 	return errs.ErrorOrNil()
 }
 
-// FetchEventIDsFromCalendar returns a list of all M365IDs of events of the targeted Calendar.
-func (c Client) FetchEventIDsFromCalendar(
+func (c Events) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, calendarID, oldDelta string,
 ) ([]string, []string, DeltaUpdate, error) {

src/internal/connector/exchange/api/mail.go

@@ -13,9 +13,21 @@ import (
 	"github.com/alcionai/corso/src/internal/connector/support"
 )
 
+// ---------------------------------------------------------------------------
+// controller
+// ---------------------------------------------------------------------------
+
+type Mail struct {
+	Client
+}
+
+// ---------------------------------------------------------------------------
+// methods
+// ---------------------------------------------------------------------------
+
 // CreateMailFolder makes a mail folder iff a folder of the same name does not exist
 // Reference: https://docs.microsoft.com/en-us/graph/api/user-post-mailfolders?view=graph-rest-1.0&tabs=http
-func (c Client) CreateMailFolder(
+func (c Mail) CreateMailFolder(
 	ctx context.Context,
 	user, folder string,
 ) (models.MailFolderable, error) {
@@ -27,7 +39,7 @@ func (c Client) CreateMailFolder(
 	return c.stable.Client().UsersById(user).MailFolders().Post(ctx, requestBody, nil)
 }
 
-func (c Client) CreateMailFolderWithParent(
+func (c Mail) CreateMailFolderWithParent(
 	ctx context.Context,
 	user, folder, parentID string,
 ) (models.MailFolderable, error) {
@@ -51,30 +63,47 @@ func (c Client) CreateMailFolderWithParent(
 
 // DeleteMailFolder removes a mail folder with the corresponding M365 ID  from the user's M365 Exchange account
 // Reference: https://docs.microsoft.com/en-us/graph/api/mailfolder-delete?view=graph-rest-1.0&tabs=http
-func (c Client) DeleteMailFolder(
+func (c Mail) DeleteMailFolder(
 	ctx context.Context,
 	user, folderID string,
 ) error {
 	return c.stable.Client().UsersById(user).MailFoldersById(folderID).Delete(ctx, nil)
 }
 
+func (c Mail) GetContainerByID(
+	ctx context.Context,
+	userID, dirID string,
+) (graph.Container, error) {
+	service, err := c.service()
+	if err != nil {
+		return nil, err
+	}
+
+	ofmf, err := optionsForMailFoldersItem([]string{"displayName", "parentFolderId"})
+	if err != nil {
+		return nil, errors.Wrap(err, "options for mail folder")
+	}
+
+	return service.Client().UsersById(userID).MailFoldersById(dirID).Get(ctx, ofmf)
+}
+
 // RetrieveMessageDataForUser is a GraphRetrievalFunc that returns message data.
-func (c Client) RetrieveMessageDataForUser(
+func (c Mail) RetrieveMessageDataForUser(
 	ctx context.Context,
 	user, m365ID string,
 ) (serialization.Parsable, error) {
 	return c.stable.Client().UsersById(user).MessagesById(m365ID).Get(ctx, nil)
 }
 
-// EnumeratetMailFolders iterates through all of the users current
+// EnumerateContainers iterates through all of the users current
 // mail folders, converting each to a graph.CacheFolder, and calling
 // fn(cf) on each one.  If fn(cf) errors, the error is aggregated
 // into a multierror that gets returned to the caller.
 // Folder hierarchy is represented in its current state, and does
 // not contain historical data.
-func (c Client) EnumerateMailFolders(
+func (c Mail) EnumerateContainers(
 	ctx context.Context,
-	userID string,
+	userID, baseDirID string,
 	fn func(graph.CacheFolder) error,
 ) error {
 	service, err := c.service()
@@ -116,22 +145,7 @@ func (c Client) EnumerateMailFolders(
 	return errs.ErrorOrNil()
 }
 
-func (c Client) GetMailFolderByID(
-	ctx context.Context,
-	userID, dirID string,
-	optionalFields ...string,
-) (models.MailFolderable, error) {
-	ofmf, err := optionsForMailFoldersItem(optionalFields)
-	if err != nil {
-		return nil, errors.Wrapf(err, "options for mail folder: %v", optionalFields)
-	}
-
-	return c.stable.Client().UsersById(userID).MailFoldersById(dirID).Get(ctx, ofmf)
-}
-
-// FetchMessageIDsFromDirectory function that returns a list of  all the m365IDs of the exchange.Mail
-// of the targeted directory
-func (c Client) FetchMessageIDsFromDirectory(
+func (c Mail) GetAddedAndRemovedItemIDs(
 	ctx context.Context,
 	user, directoryID, oldDelta string,
 ) ([]string, []string, DeltaUpdate, error) {

src/internal/connector/exchange/contact_folder_cache.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/alcionai/corso/src/internal/connector/exchange/api"
 	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/pkg/path"
@@ -15,7 +14,8 @@ var _ graph.ContainerResolver = &contactFolderCache{}
 
 type contactFolderCache struct {
 	*containerResolver
-	ac     api.Client
+	enumer containersEnumerator
+	getter containerGetter
 	userID string
 }
 
@@ -24,7 +24,7 @@ func (cfc *contactFolderCache) populateContactRoot(
 	directoryID string,
 	baseContainerPath []string,
 ) error {
-	f, err := cfc.ac.GetContactFolderByID(ctx, cfc.userID, directoryID)
+	f, err := cfc.getter.GetContainerByID(ctx, cfc.userID, directoryID)
 	if err != nil {
 		return errors.Wrapf(
 			err,
@@ -53,7 +53,7 @@ func (cfc *contactFolderCache) Populate(
 		return err
 	}
 
-	err := cfc.ac.EnumerateContactsFolders(ctx, cfc.userID, baseID, cfc.addFolder)
+	err := cfc.enumer.EnumerateContainers(ctx, cfc.userID, baseID, cfc.addFolder)
 	if err != nil {
 		return err
 	}

src/internal/connector/exchange/container_resolver.go

@@ -10,6 +10,29 @@ import (
 	"github.com/alcionai/corso/src/pkg/path"
 )
 
+// ---------------------------------------------------------------------------
+// common interfaces
+// ---------------------------------------------------------------------------
+
+type containerGetter interface {
+	GetContainerByID(
+		ctx context.Context,
+		userID, dirID string,
+	) (graph.Container, error)
+}
+
+type containersEnumerator interface {
+	EnumerateContainers(
+		ctx context.Context,
+		userID, baseDirID string,
+		fn func(graph.CacheFolder) error,
+	) error
+}
+
+// ---------------------------------------------------------------------------
+// controller
+// ---------------------------------------------------------------------------
+
 // Exchange has a limit of 300 for folder depth. OneDrive has a limit on path
 // length of 400 characters (including separators) which would be roughly 200
 // folders if each folder is only a single character.

src/internal/connector/exchange/data_collections.go

@@ -8,6 +8,7 @@ import (
 	"github.com/hashicorp/go-multierror"
 	"github.com/pkg/errors"
 
+	"github.com/alcionai/corso/src/internal/connector/exchange/api"
 	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/internal/data"
@@ -205,12 +206,25 @@ func DataCollections(
 	return collections, errs
 }
 
+func getterByType(ac api.Client, category path.CategoryType) (addedAndRemovedItemIDsGetter, error) {
+	switch category {
+	case path.EmailCategory:
+		return ac.Mail(), nil
+	case path.EventsCategory:
+		return ac.Events(), nil
+	case path.ContactsCategory:
+		return ac.Contacts(), nil
+	default:
+		return nil, fmt.Errorf("category %s not supported by getFetchIDFunc", category)
+	}
+}
+
 // createCollections - utility function that retrieves M365
 // IDs through Microsoft Graph API. The selectors.ExchangeScope
 // determines the type of collections that are retrieved.
 func createCollections(
 	ctx context.Context,
-	acct account.M365Config,
+	creds account.M365Config,
 	user string,
 	scope selectors.ExchangeScope,
 	dps DeltaPaths,
@@ -220,15 +234,22 @@ func createCollections(
 	var (
 		errs           *multierror.Error
 		allCollections = make([]data.Collection, 0)
+		ac             = api.Client{Credentials: creds}
+		category       = scope.Category().PathType()
 	)
 
+	getter, err := getterByType(ac, category)
+	if err != nil {
+		return nil, err
+	}
+
 	// Create collection of ExchangeDataCollection
 	collections := make(map[string]data.Collection)
 
 	qp := graph.QueryParams{
-		Category:      scope.Category().PathType(),
+		Category:      category,
 		ResourceOwner: user,
-		Credentials:   acct,
+		Credentials:   creds,
 	}
 
 	foldersComplete, closer := observe.MessageWithCompletion(fmt.Sprintf("∙ %s - %s:", qp.Category, user))
@@ -243,6 +264,7 @@ func createCollections(
 	err = filterContainersAndFillCollections(
 		ctx,
 		qp,
+		getter,
 		collections,
 		su,
 		resolver,

src/internal/connector/exchange/event_calendar_cache.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/alcionai/corso/src/internal/connector/exchange/api"
 	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/pkg/path"
 )
@@ -14,7 +13,7 @@ var _ graph.ContainerResolver = &eventCalendarCache{}
 
 type eventCalendarCache struct {
 	*containerResolver
-	ac     api.Client
+	enumer containersEnumerator
 	userID string
 }
 
@@ -30,7 +29,7 @@ func (ecc *eventCalendarCache) Populate(
 		ecc.containerResolver = newContainerResolver()
 	}
 
-	err := ecc.ac.EnumerateCalendars(ctx, ecc.userID, ecc.addFolder)
+	err := ecc.enumer.EnumerateContainers(ctx, ecc.userID, "", ecc.addFolder)
 	if err != nil {
 		return err
 	}

src/internal/connector/exchange/exchange_data_collection.go

@@ -142,11 +142,11 @@ func (col *Collection) Items() <-chan data.Stream {
 func GetQueryAndSerializeFunc(ac api.Client, category path.CategoryType) (api.GraphRetrievalFunc, GraphSerializeFunc) {
 	switch category {
 	case path.ContactsCategory:
-		return ac.RetrieveContactDataForUser, serializeAndStreamContact
+		return ac.Contacts().RetrieveContactDataForUser, serializeAndStreamContact
 	case path.EventsCategory:
-		return ac.RetrieveEventDataForUser, serializeAndStreamEvent
+		return ac.Events().RetrieveEventDataForUser, serializeAndStreamEvent
 	case path.EmailCategory:
-		return ac.RetrieveMessageDataForUser, serializeAndStreamMessage
+		return ac.Mail().RetrieveMessageDataForUser, serializeAndStreamMessage
 	// Unsupported options returns nil, nil
 	default:
 		return nil, nil

src/internal/connector/exchange/folder_resolver_test.go

@@ -50,14 +50,15 @@ func (suite *CacheResolverSuite) TestPopulate() {
 	eventFunc := func(t *testing.T) graph.ContainerResolver {
 		return &eventCalendarCache{
 			userID: tester.M365UserID(t),
-			ac:     ac,
+			enumer: ac.Events(),
 		}
 	}
 
 	contactFunc := func(t *testing.T) graph.ContainerResolver {
 		return &contactFolderCache{
 			userID: tester.M365UserID(t),
-			ac:     ac,
+			enumer: ac.Contacts(),
+			getter: ac.Contacts(),
 		}
 	}
 

src/internal/connector/exchange/mail_folder_cache.go

@@ -5,7 +5,6 @@ import (
 
 	"github.com/pkg/errors"
 
-	"github.com/alcionai/corso/src/internal/connector/exchange/api"
 	"github.com/alcionai/corso/src/internal/connector/graph"
 	"github.com/alcionai/corso/src/internal/connector/support"
 	"github.com/alcionai/corso/src/pkg/path"
@@ -18,7 +17,8 @@ var _ graph.ContainerResolver = &mailFolderCache{}
 // nameLookup map: Key: DisplayName Value: ID
 type mailFolderCache struct {
 	*containerResolver
-	ac     api.Client
+	enumer containersEnumerator
+	getter containerGetter
 	userID string
 }
 
@@ -33,7 +33,7 @@ func (mc *mailFolderCache) populateMailRoot(
 	for _, fldr := range []string{rootFolderAlias, DefaultMailFolder} {
 		var directory string
 
-		f, err := mc.ac.GetMailFolderByID(ctx, mc.userID, fldr, "displayName", "parentFolderId")
+		f, err := mc.getter.GetContainerByID(ctx, mc.userID, fldr)
 		if err != nil {
 			return errors.Wrap(err, "fetching root folder"+support.ConnectorStackErrorTrace(err))
 		}
@@ -65,7 +65,7 @@ func (mc *mailFolderCache) Populate(
 		return err
 	}
 
-	err := mc.ac.EnumerateMailFolders(ctx, mc.userID, mc.addFolder)
+	err := mc.enumer.EnumerateContainers(ctx, mc.userID, "", mc.addFolder)
 	if err != nil {
 		return err
 	}

src/internal/connector/exchange/mail_folder_cache_test.go

@@ -84,9 +84,12 @@ func (suite *MailFolderCacheIntegrationSuite) TestDeltaFetch() {
 			ac, err := api.NewClient(suite.credentials)
 			require.NoError(t, err)
 
+			acm := ac.Mail()
+
 			mfc := mailFolderCache{
 				userID: userID,
-				ac:     ac,
+				enumer: acm,
+				getter: acm,
 			}
 
 			require.NoError(t, mfc.Populate(ctx, test.root, test.path...))

src/internal/connector/exchange/restore_test.go

@@ -69,14 +69,14 @@ func (suite *ExchangeRestoreSuite) TestRestoreContact() {
 		folderName = "TestRestoreContact: " + common.FormatSimpleDateTime(now)
 	)
 
-	aFolder, err := suite.ac.CreateContactFolder(ctx, userID, folderName)
+	aFolder, err := suite.ac.Contacts().CreateContactFolder(ctx, userID, folderName)
 	require.NoError(t, err)
 
 	folderID := *aFolder.GetId()
 
 	defer func() {
 		// Remove the folder containing contact prior to exiting test
-		err = suite.ac.DeleteContactFolder(ctx, userID, folderID)
+		err = suite.ac.Contacts().DeleteContactFolder(ctx, userID, folderID)
 		assert.NoError(t, err)
 	}()
 
@@ -103,14 +103,14 @@ func (suite *ExchangeRestoreSuite) TestRestoreEvent() {
 		name   = "TestRestoreEvent: " + common.FormatSimpleDateTime(time.Now())
 	)
 
-	calendar, err := suite.ac.CreateCalendar(ctx, userID, name)
+	calendar, err := suite.ac.Events().CreateCalendar(ctx, userID, name)
 	require.NoError(t, err)
 
 	calendarID := *calendar.GetId()
 
 	defer func() {
 		// Removes calendar containing events created during the test
-		err = suite.ac.DeleteCalendar(ctx, userID, calendarID)
+		err = suite.ac.Events().DeleteCalendar(ctx, userID, calendarID)
 		assert.NoError(t, err)
 	}()
 
@@ -146,10 +146,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Mail",
 			bytes:       mockconnector.GetMockMessageBytes("Restore Exchange Object"),
 			category:    path.EmailCategory,
-			cleanupFunc: suite.ac.DeleteMailFolder,
+			cleanupFunc: suite.ac.Mail().DeleteMailFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreMailObject: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateMailFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Mail().CreateMailFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -159,10 +159,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Mail: One Direct Attachment",
 			bytes:       mockconnector.GetMockMessageWithDirectAttachment("Restore 1 Attachment"),
 			category:    path.EmailCategory,
-			cleanupFunc: suite.ac.DeleteMailFolder,
+			cleanupFunc: suite.ac.Mail().DeleteMailFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreMailwithAttachment: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateMailFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Mail().CreateMailFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -172,10 +172,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Mail: One Large Attachment",
 			bytes:       mockconnector.GetMockMessageWithLargeAttachment("Restore Large Attachment"),
 			category:    path.EmailCategory,
-			cleanupFunc: suite.ac.DeleteMailFolder,
+			cleanupFunc: suite.ac.Mail().DeleteMailFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreMailwithLargeAttachment: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateMailFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Mail().CreateMailFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -185,10 +185,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Mail: Two Attachments",
 			bytes:       mockconnector.GetMockMessageWithTwoAttachments("Restore 2 Attachments"),
 			category:    path.EmailCategory,
-			cleanupFunc: suite.ac.DeleteMailFolder,
+			cleanupFunc: suite.ac.Mail().DeleteMailFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreMailwithAttachments: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateMailFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Mail().CreateMailFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -198,10 +198,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Mail: Reference(OneDrive) Attachment",
 			bytes:       mockconnector.GetMessageWithOneDriveAttachment("Restore Reference(OneDrive) Attachment"),
 			category:    path.EmailCategory,
-			cleanupFunc: suite.ac.DeleteMailFolder,
+			cleanupFunc: suite.ac.Mail().DeleteMailFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreMailwithReferenceAttachment: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateMailFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Mail().CreateMailFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -212,10 +212,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Contact",
 			bytes:       mockconnector.GetMockContactBytes("Test_Omega"),
 			category:    path.ContactsCategory,
-			cleanupFunc: suite.ac.DeleteContactFolder,
+			cleanupFunc: suite.ac.Contacts().DeleteContactFolder,
 			destination: func(t *testing.T, ctx context.Context) string {
 				folderName := "TestRestoreContactObject: " + common.FormatSimpleDateTime(now)
-				folder, err := suite.ac.CreateContactFolder(ctx, userID, folderName)
+				folder, err := suite.ac.Contacts().CreateContactFolder(ctx, userID, folderName)
 				require.NoError(t, err)
 
 				return *folder.GetId()
@@ -225,10 +225,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Events",
 			bytes:       mockconnector.GetDefaultMockEventBytes("Restored Event Object"),
 			category:    path.EventsCategory,
-			cleanupFunc: suite.ac.DeleteCalendar,
+			cleanupFunc: suite.ac.Events().DeleteCalendar,
 			destination: func(t *testing.T, ctx context.Context) string {
 				calendarName := "TestRestoreEventObject: " + common.FormatSimpleDateTime(now)
-				calendar, err := suite.ac.CreateCalendar(ctx, userID, calendarName)
+				calendar, err := suite.ac.Events().CreateCalendar(ctx, userID, calendarName)
 				require.NoError(t, err)
 
 				return *calendar.GetId()
@@ -238,10 +238,10 @@ func (suite *ExchangeRestoreSuite) TestRestoreExchangeObject() {
 			name:        "Test Event with Attachment",
 			bytes:       mockconnector.GetMockEventWithAttachment("Restored Event Attachment"),
 			category:    path.EventsCategory,
-			cleanupFunc: suite.ac.DeleteCalendar,
+			cleanupFunc: suite.ac.Events().DeleteCalendar,
 			destination: func(t *testing.T, ctx context.Context) string {
 				calendarName := "TestRestoreEventObject_" + common.FormatSimpleDateTime(now)
-				calendar, err := suite.ac.CreateCalendar(ctx, userID, calendarName)
+				calendar, err := suite.ac.Events().CreateCalendar(ctx, userID, calendarName)
 				require.NoError(t, err)
 
 				return *calendar.GetId()

src/internal/connector/exchange/service_functions.go

@@ -48,23 +48,27 @@ func PopulateExchangeContainerResolver(
 
 	switch qp.Category {
 	case path.EmailCategory:
+		acm := ac.Mail()
 		res = &mailFolderCache{
 			userID: qp.ResourceOwner,
-			ac:     ac,
+			getter: acm,
+			enumer: acm,
 		}
 		cacheRoot = rootFolderAlias
 
 	case path.ContactsCategory:
+		acc := ac.Contacts()
 		res = &contactFolderCache{
 			userID: qp.ResourceOwner,
-			ac:     ac,
+			getter: acc,
+			enumer: acc,
 		}
 		cacheRoot = DefaultContactFolder
 
 	case path.EventsCategory:
 		res = &eventCalendarCache{
 			userID: qp.ResourceOwner,
-			ac:     ac,
+			enumer: ac.Events(),
 		}
 		cacheRoot = DefaultCalendar
 

src/internal/connector/exchange/service_iterators.go

@@ -2,7 +2,6 @@ package exchange
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/pkg/errors"
 
@@ -16,6 +15,13 @@ import (
 	"github.com/alcionai/corso/src/pkg/selectors"
 )
 
+type addedAndRemovedItemIDsGetter interface {
+	GetAddedAndRemovedItemIDs(
+		ctx context.Context,
+		user, containerID, oldDeltaToken string,
+	) ([]string, []string, api.DeltaUpdate, error)
+}
+
 // filterContainersAndFillCollections is a utility function
 // that places the M365 object ids belonging to specific directories
 // into a Collection. Messages outside of those directories are omitted.
@@ -24,6 +30,7 @@ import (
 func filterContainersAndFillCollections(
 	ctx context.Context,
 	qp graph.QueryParams,
+	getter addedAndRemovedItemIDsGetter,
 	collections map[string]data.Collection,
 	statusUpdater support.StatusUpdater,
 	resolver graph.ContainerResolver,
@@ -41,17 +48,14 @@ func filterContainersAndFillCollections(
 		tombstones = makeTombstones(dps)
 	)
 
-	// TODO(rkeepers): pass in the api client instead of generating it here.
+	// TODO(rkeepers): this should be passed in from the caller, probably
+	// as an interface that satisfies the NewCollection requirements.
+	// But this will work for the short term.
 	ac, err := api.NewClient(qp.Credentials)
 	if err != nil {
 		return err
 	}
 
-	getJobs, err := getFetchIDFunc(ac, qp.Category)
-	if err != nil {
-		return support.WrapAndAppend(qp.ResourceOwner, err, errs)
-	}
-
 	for _, c := range resolver.Items() {
 		if ctrlOpts.FailFast && errs != nil {
 			return errs
@@ -89,7 +93,7 @@ func filterContainersAndFillCollections(
 			}
 		}
 
-		added, removed, newDelta, err := getJobs(ctx, qp.ResourceOwner, cID, prevDelta)
+		added, removed, newDelta, err := getter.GetAddedAndRemovedItemIDs(ctx, qp.ResourceOwner, cID, prevDelta)
 		if err != nil {
 			if graph.IsErrDeletedInFlight(err) == nil {
 				errs = support.WrapAndAppend(qp.ResourceOwner, err, errs)
@@ -217,24 +221,3 @@ func pathFromPrevString(ps string) (path.Path, error) {
 
 	return p, nil
 }
-
-// FetchIDFunc collection of helper functions which return a list of all item
-// IDs in the given container and a delta token for future requests if the
-// container supports fetching delta records.
-type FetchIDFunc func(
-	ctx context.Context,
-	user, containerID, oldDeltaToken string,
-) ([]string, []string, api.DeltaUpdate, error)
-
-func getFetchIDFunc(ac api.Client, category path.CategoryType) (FetchIDFunc, error) {
-	switch category {
-	case path.EmailCategory:
-		return ac.FetchMessageIDsFromDirectory, nil
-	case path.EventsCategory:
-		return ac.FetchEventIDsFromCalendar, nil
-	case path.ContactsCategory:
-		return ac.FetchContactIDsFromDirectory, nil
-	default:
-		return nil, fmt.Errorf("category %s not supported by getFetchIDFunc", category)
-	}
-}

src/internal/connector/exchange/service_restore.go

@@ -455,9 +455,11 @@ func CreateContainerDestinaion(
 	switch category {
 	case path.EmailCategory:
 		if directoryCache == nil {
+			acm := ac.Mail()
 			mfc := &mailFolderCache{
 				userID: user,
-				ac:     ac,
+				enumer: acm,
+				getter: acm,
 			}
 
 			caches[category] = mfc
@@ -475,9 +477,11 @@ func CreateContainerDestinaion(
 
 	case path.ContactsCategory:
 		if directoryCache == nil {
+			acc := ac.Contacts()
 			cfc := &contactFolderCache{
 				userID: user,
-				ac:     ac,
+				enumer: acc,
+				getter: acc,
 			}
 			caches[category] = cfc
 			newCache = true
@@ -496,7 +500,7 @@ func CreateContainerDestinaion(
 		if directoryCache == nil {
 			ecc := &eventCalendarCache{
 				userID: user,
-				ac:     ac,
+				enumer: ac.Events(),
 			}
 			caches[category] = ecc
 			newCache = true
@@ -543,7 +547,7 @@ func establishMailRestoreLocation(
 			continue
 		}
 
-		temp, err := ac.CreateMailFolderWithParent(ctx, user, folder, folderID)
+		temp, err := ac.Mail().CreateMailFolderWithParent(ctx, user, folder, folderID)
 		if err != nil {
 			// Should only error if cache malfunctions or incorrect parameters
 			return "", errors.Wrap(err, support.ConnectorStackErrorTrace(err))
@@ -590,7 +594,7 @@ func establishContactsRestoreLocation(
 		return cached, nil
 	}
 
-	temp, err := ac.CreateContactFolder(ctx, user, folders[0])
+	temp, err := ac.Contacts().CreateContactFolder(ctx, user, folders[0])
 	if err != nil {
 		return "", errors.Wrap(err, support.ConnectorStackErrorTrace(err))
 	}
@@ -623,7 +627,7 @@ func establishEventsRestoreLocation(
 		return cached, nil
 	}
 
-	temp, err := ac.CreateCalendar(ctx, user, folders[0])
+	temp, err := ac.Events().CreateCalendar(ctx, user, folders[0])
 	if err != nil {
 		return "", errors.Wrap(err, support.ConnectorStackErrorTrace(err))
 	}

src/internal/operations/backup_integration_test.go

@@ -942,7 +942,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 
 					switch category {
 					case path.EmailCategory:
-						ids, _, _, err := ac.FetchMessageIDsFromDirectory(ctx, suite.user, containerID, "")
+						ids, _, _, err := ac.Mail().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
 						require.NoError(t, err, "getting message ids")
 						require.NotEmpty(t, ids, "message ids in folder")
 
@@ -950,7 +950,7 @@ func (suite *BackupOpIntegrationSuite) TestBackup_Run_exchangeIncrementals() {
 						require.NoError(t, err, "deleting email item: %s", support.ConnectorStackErrorTrace(err))
 
 					case path.ContactsCategory:
-						ids, _, _, err := ac.FetchContactIDsFromDirectory(ctx, suite.user, containerID, "")
+						ids, _, _, err := ac.Contacts().GetAddedAndRemovedItemIDs(ctx, suite.user, containerID, "")
 						require.NoError(t, err, "getting contact ids")
 						require.NotEmpty(t, ids, "contact ids in folder")