port `DocumentKey` to non-container types of `Model/*` (#930)

* naively remove FSTPath import and source/test files.

* port FieldPath, part I

* port FieldPath, part II

* port ResourcePath, part I

* port ResourcePath, part II

* the grand commit to fix build errors

* use testutil:: helper instead of those from FSTHelpers

* fix test and lint

* use c_str in errmsg directly

* fix

* fix

* make code clean

* fix integration test I missed

* fix to avoid naming collision in preprocessor

* address changes

* address changes

* address changes

* fix: fieldMask are actually shared with different context.

* address changes

* add converter function between two DocumentKey implementations

* add unit test

* address changes

* fix lint

* using DocumentKey in model except for the container types `FSTDocumentDictionary`, `FSTDocumentKeySet`, and  `FSTDocumentVersionDictionary`

* change other place w.r.t. the use of `DocumentKey` in model

* update parameter of test helpers from NSString to string_view

* revert a temporary change used in debug

* address changes

4 files changed, 152 insertions, 145 deletions

diff --git a/Firestore/Example/Tests/Local/FSTLocalSerializerTests.mm b/Firestore/Example/Tests/Local/FSTLocalSerializerTests.mm
index 87242fa..d94925d 100644
--- a/Firestore/Example/Tests/Local/FSTLocalSerializerTests.mm
+++ b/Firestore/Example/Tests/Local/FSTLocalSerializerTests.mm
@@ -126,7 +126,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (void)testEncodesDocumentAsMaybeDocument {
-  FSTDocument *doc = FSTTestDoc(@"some/path", 42, @{@"foo" : @"bar"}, NO);
+  FSTDocument *doc = FSTTestDoc("some/path", 42, @{@"foo" : @"bar"}, NO);
 
   FSTPBMaybeDocument *maybeDocProto = [FSTPBMaybeDocument message];
   maybeDocProto.document = [GCFSDocument message];
@@ -143,7 +143,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (void)testEncodesDeletedDocumentAsMaybeDocument {
-  FSTDeletedDocument *deletedDoc = FSTTestDeletedDoc(@"some/path", 42);
+  FSTDeletedDocument *deletedDoc = FSTTestDeletedDoc("some/path", 42);
 
   FSTPBMaybeDocument *maybeDocProto = [FSTPBMaybeDocument message];
   maybeDocProto.noDocument = [FSTPBNoDocument message];
diff --git a/Firestore/Example/Tests/Local/FSTLocalStoreTests.mm b/Firestore/Example/Tests/Local/FSTLocalStoreTests.mm
index 5a386b6..7c3b977 100644
--- a/Firestore/Example/Tests/Local/FSTLocalStoreTests.mm
+++ b/Firestore/Example/Tests/Local/FSTLocalStoreTests.mm
@@ -237,25 +237,25 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   if ([self isTestBaseClass]) return;
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   [self acknowledgeMutationWithVersion:0];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, NO));
 }
 
 - (void)testHandlesSetMutationThenDocument {
   if ([self isTestBaseClass]) return;
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   [self applyRemoteEvent:FSTTestUpdateRemoteEvent(
-                             FSTTestDoc(@"foo/bar", 2, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, YES));
+                             FSTTestDoc("foo/bar", 2, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, YES));
 }
 
 - (void)testHandlesAckThenRejectThenRemoteEvent {
@@ -266,76 +266,76 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   [self allocateQuery:query];
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   // The last seen version is zero, so this ack must be held.
   [self acknowledgeMutationWithVersion:1];
   FSTAssertChanged(@[]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   [self writeMutation:FSTTestSetMutation(@"bar/baz", @{@"bar" : @"baz"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"bar/baz", 0, @{@"bar" : @"baz"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"bar/baz", 0, @{@"bar" : @"baz"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("bar/baz", 0, @{@"bar" : @"baz"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("bar/baz", 0, @{@"bar" : @"baz"}, YES));
 
   [self rejectMutation];
   FSTAssertRemoved(@[ @"bar/baz" ]);
   FSTAssertNotContains(@"bar/baz");
 
   [self applyRemoteEvent:FSTTestUpdateRemoteEvent(
-                             FSTTestDoc(@"foo/bar", 2, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 2, @{@"it" : @"changed"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"it" : @"changed"}, NO));
+                             FSTTestDoc("foo/bar", 2, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 2, @{@"it" : @"changed"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"it" : @"changed"}, NO));
   FSTAssertNotContains(@"bar/baz");
 }
 
 - (void)testHandlesDeletedDocumentThenSetMutationThenAck {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc(@"foo/bar", 2), @[ @1 ], @[])];
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc("foo/bar", 2), @[ @1 ], @[])];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 2));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 2));
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   [self acknowledgeMutationWithVersion:3];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, NO));
 }
 
 - (void)testHandlesSetMutationThenDeletedDocument {
   if ([self isTestBaseClass]) return;
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc(@"foo/bar", 2), @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc("foo/bar", 2), @[ @1 ], @[])];
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 }
 
 - (void)testHandlesDocumentThenSetMutationThenAckThenDocument {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 2, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 2, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 2, @{@"it" : @"base"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"it" : @"base"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 2, @{@"it" : @"base"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"it" : @"base"}, NO));
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"bar"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, YES));
 
   [self acknowledgeMutationWithVersion:3];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, NO));
 
   [self applyRemoteEvent:FSTTestUpdateRemoteEvent(
-                             FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO));
+                             FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO));
 }
 
 - (void)testHandlesPatchWithoutPriorDocument {
@@ -357,14 +357,14 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   FSTAssertRemoved(@[ @"foo/bar" ]);
   FSTAssertNotContains(@"foo/bar");
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, YES));
 
   [self acknowledgeMutationWithVersion:2];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar", @"it" : @"base"}, NO));
 }
 
 - (void)testHandlesPatchMutationThenAckThenDocument {
@@ -378,10 +378,10 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   FSTAssertRemoved(@[ @"foo/bar" ]);
   FSTAssertNotContains(@"foo/bar");
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO));
 }
 
 - (void)testHandlesDeleteMutationThenAck {
@@ -389,28 +389,28 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 
   [self writeMutation:FSTTestDeleteMutation(@"foo/bar")];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self acknowledgeMutationWithVersion:1];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 }
 
 - (void)testHandlesDocumentThenDeleteMutationThenAck {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO));
 
   [self writeMutation:FSTTestDeleteMutation(@"foo/bar")];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self acknowledgeMutationWithVersion:2];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 }
 
 - (void)testHandlesDeleteMutationThenDocumentThenAck {
@@ -418,59 +418,59 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 
   [self writeMutation:FSTTestDeleteMutation(@"foo/bar")];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self acknowledgeMutationWithVersion:2];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 }
 
 - (void)testHandlesDocumentThenDeletedDocumentThenDocument {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO));
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc(@"foo/bar", 2), @[ @1 ], @[])];
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc("foo/bar", 2), @[ @1 ], @[])];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 2));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 2));
 
   [self applyRemoteEvent:FSTTestUpdateRemoteEvent(
-                             FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 3, @{@"it" : @"changed"}, NO));
+                             FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO), @[ @1 ], @[])];
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 3, @{@"it" : @"changed"}, NO));
 }
 
 - (void)testHandlesSetMutationThenPatchMutationThenDocumentThenAckThenAck {
   if ([self isTestBaseClass]) return;
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"old"})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, YES));
 
   [self writeMutation:FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"it" : @"base"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"it" : @"base"}, NO),
                                                   @[ @1 ], @[])];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, YES));
 
   [self acknowledgeMutationWithVersion:2];  // delete mutation
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, YES));
 
   [self acknowledgeMutationWithVersion:3];  // patch mutation
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO));
 }
 
 - (void)testHandlesSetMutationAndPatchMutationTogether {
@@ -481,8 +481,8 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
     FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})
   ]];
 
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 }
 
 - (void)testHandlesSetMutationThenPatchMutationThenReject {
@@ -490,14 +490,14 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 
   [self writeMutation:FSTTestSetMutation(@"foo/bar", @{@"foo" : @"old"})];
   [self acknowledgeMutationWithVersion:1];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, NO));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, NO));
 
   [self writeMutation:FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
 
   [self rejectMutation];
-  FSTAssertChanged(@[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, NO) ]);
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, NO));
+  FSTAssertChanged(@[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, NO) ]);
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, NO));
 }
 
 - (void)testHandlesSetMutationsAndPatchMutationOfJustOneTogether {
@@ -510,11 +510,11 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   ]];
 
   FSTAssertChanged((@[
-    FSTTestDoc(@"bar/baz", 0, @{@"bar" : @"baz"}, YES),
-    FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES)
+    FSTTestDoc("bar/baz", 0, @{@"bar" : @"baz"}, YES),
+    FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES)
   ]));
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
-  FSTAssertContains(FSTTestDoc(@"bar/baz", 0, @{@"bar" : @"baz"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertContains(FSTTestDoc("bar/baz", 0, @{@"bar" : @"baz"}, YES));
 }
 
 - (void)testHandlesDeleteMutationThenPatchMutationThenAckThenAck {
@@ -522,31 +522,31 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 
   [self writeMutation:FSTTestDeleteMutation(@"foo/bar")];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self writeMutation:FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})];
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self acknowledgeMutationWithVersion:2];  // delete mutation
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 
   [self acknowledgeMutationWithVersion:3];  // patch mutation
   FSTAssertRemoved(@[ @"foo/bar" ]);
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/bar", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/bar", 0));
 }
 
 - (void)testCollectsGarbageAfterChangeBatchWithNoTargetIDs {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc(@"foo/bar", 2), @[ @1 ], @[])];
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDeletedDoc("foo/bar", 2), @[ @1 ], @[])];
   FSTAssertRemoved(@[ @"foo/bar" ]);
 
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, NO),
                                                   @[ @1 ], @[])];
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
@@ -559,12 +559,12 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   [self allocateQuery:query];
   FSTAssertTargetID(2);
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, NO),
                                                   @[ @2 ], @[])];
   [self collectGarbage];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"bar"}, NO));
+  FSTAssertContains(FSTTestDoc("foo/bar", 2, @{@"foo" : @"bar"}, NO));
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 2, @{@"foo" : @"baz"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 2, @{@"foo" : @"baz"}, NO),
                                                   @[], @[ @2 ])];
   [self collectGarbage];
 
@@ -574,27 +574,27 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 - (void)testCollectsGarbageAfterAcknowledgedMutation {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, NO),
                                                   @[ @1 ], @[])];
   [self writeMutation:FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})];
   [self writeMutation:FSTTestSetMutation(@"foo/bah", @{@"foo" : @"bah"})];
   [self writeMutation:FSTTestDeleteMutation(@"foo/baz")];
   [self collectGarbage];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
-  FSTAssertContains(FSTTestDoc(@"foo/bah", 0, @{@"foo" : @"bah"}, YES));
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bah", 0, @{@"foo" : @"bah"}, YES));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self acknowledgeMutationWithVersion:3];
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
-  FSTAssertContains(FSTTestDoc(@"foo/bah", 0, @{@"foo" : @"bah"}, YES));
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDoc("foo/bah", 0, @{@"foo" : @"bah"}, YES));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self acknowledgeMutationWithVersion:4];
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
   FSTAssertNotContains(@"foo/bah");
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self acknowledgeMutationWithVersion:5];
   [self collectGarbage];
@@ -606,27 +606,27 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
 - (void)testCollectsGarbageAfterRejectedMutation {
   if ([self isTestBaseClass]) return;
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"old"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 0, @{@"foo" : @"old"}, NO),
                                                   @[ @1 ], @[])];
   [self writeMutation:FSTTestPatchMutation("foo/bar", @{@"foo" : @"bar"}, {})];
   [self writeMutation:FSTTestSetMutation(@"foo/bah", @{@"foo" : @"bah"})];
   [self writeMutation:FSTTestDeleteMutation(@"foo/baz")];
   [self collectGarbage];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES));
-  FSTAssertContains(FSTTestDoc(@"foo/bah", 0, @{@"foo" : @"bah"}, YES));
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bah", 0, @{@"foo" : @"bah"}, YES));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self rejectMutation];  // patch mutation
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
-  FSTAssertContains(FSTTestDoc(@"foo/bah", 0, @{@"foo" : @"bah"}, YES));
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDoc("foo/bah", 0, @{@"foo" : @"bah"}, YES));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self rejectMutation];  // set mutation
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
   FSTAssertNotContains(@"foo/bah");
-  FSTAssertContains(FSTTestDeletedDoc(@"foo/baz", 0));
+  FSTAssertContains(FSTTestDeletedDoc("foo/baz", 0));
 
   [self rejectMutation];  // delete mutation
   [self collectGarbage];
@@ -642,22 +642,22 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   [self allocateQuery:query];
   FSTAssertTargetID(2);
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO),
                                                   @[ @2 ], @[])];
   [self writeMutation:FSTTestSetMutation(@"foo/baz", @{@"foo" : @"baz"})];
   [self collectGarbage];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO));
-  FSTAssertContains(FSTTestDoc(@"foo/baz", 0, @{@"foo" : @"baz"}, YES));
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO));
+  FSTAssertContains(FSTTestDoc("foo/baz", 0, @{@"foo" : @"baz"}, YES));
 
   [self notifyLocalViewChanges:FSTTestViewChanges(query, @[ @"foo/bar", @"foo/baz" ], @[])];
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO),
                                                   @[], @[ @2 ])];
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/baz", 2, @{@"foo" : @"baz"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/baz", 2, @{@"foo" : @"baz"}, NO),
                                                   @[ @1 ], @[])];
   [self acknowledgeMutationWithVersion:2];
   [self collectGarbage];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{@"foo" : @"bar"}, NO));
-  FSTAssertContains(FSTTestDoc(@"foo/baz", 2, @{@"foo" : @"baz"}, NO));
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{@"foo" : @"bar"}, NO));
+  FSTAssertContains(FSTTestDoc("foo/baz", 2, @{@"foo" : @"baz"}, NO));
 
   [self notifyLocalViewChanges:FSTTestViewChanges(query, @[], @[ @"foo/bar", @"foo/baz" ])];
   [self collectGarbage];
@@ -670,9 +670,9 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   if ([self isTestBaseClass]) return;
 
   FSTTargetID targetID = 321;
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 1, @{}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 1, @{}, NO),
                                                   @[ @(targetID) ], @[])];
-  FSTAssertContains(FSTTestDoc(@"foo/bar", 1, @{}, NO));
+  FSTAssertContains(FSTTestDoc("foo/bar", 1, @{}, NO));
 
   [self collectGarbage];
   FSTAssertNotContains(@"foo/bar");
@@ -688,7 +688,7 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   ]];
   FSTQuery *query = FSTTestQuery("foo/bar");
   FSTDocumentDictionary *docs = [self.localStore executeQuery:query];
-  XCTAssertEqualObjects([docs values], @[ FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
+  XCTAssertEqualObjects([docs values], @[ FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES) ]);
 }
 
 - (void)testCanExecuteCollectionQueries {
@@ -704,8 +704,8 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   FSTQuery *query = FSTTestQuery("foo");
   FSTDocumentDictionary *docs = [self.localStore executeQuery:query];
   XCTAssertEqualObjects([docs values], (@[
-                          FSTTestDoc(@"foo/bar", 0, @{@"foo" : @"bar"}, YES),
-                          FSTTestDoc(@"foo/baz", 0, @{@"foo" : @"baz"}, YES)
+                          FSTTestDoc("foo/bar", 0, @{@"foo" : @"bar"}, YES),
+                          FSTTestDoc("foo/baz", 0, @{@"foo" : @"baz"}, YES)
                         ]));
 }
 
@@ -716,18 +716,18 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   [self allocateQuery:query];
   FSTAssertTargetID(2);
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/baz", 10, @{@"a" : @"b"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/baz", 10, @{@"a" : @"b"}, NO),
                                                   @[ @2 ], @[])];
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 20, @{@"a" : @"b"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 20, @{@"a" : @"b"}, NO),
                                                   @[ @2 ], @[])];
 
   [self.localStore locallyWriteMutations:@[ FSTTestSetMutation(@"foo/bonk", @{@"a" : @"b"}) ]];
 
   FSTDocumentDictionary *docs = [self.localStore executeQuery:query];
   XCTAssertEqualObjects([docs values], (@[
-                          FSTTestDoc(@"foo/bar", 20, @{@"a" : @"b"}, NO),
-                          FSTTestDoc(@"foo/baz", 10, @{@"a" : @"b"}, NO),
-                          FSTTestDoc(@"foo/bonk", 0, @{@"a" : @"b"}, YES)
+                          FSTTestDoc("foo/bar", 20, @{@"a" : @"b"}, NO),
+                          FSTTestDoc("foo/baz", 10, @{@"a" : @"b"}, NO),
+                          FSTTestDoc("foo/bonk", 0, @{@"a" : @"b"}, YES)
                         ]));
 }
 
@@ -775,9 +775,9 @@ FSTDocumentVersionDictionary *FSTVersionDictionary(FSTMutation *mutation,
   [self allocateQuery:query];
   FSTAssertTargetID(2);
 
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/baz", 10, @{@"a" : @"b"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/baz", 10, @{@"a" : @"b"}, NO),
                                                   @[ @2 ], @[])];
-  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc(@"foo/bar", 20, @{@"a" : @"b"}, NO),
+  [self applyRemoteEvent:FSTTestUpdateRemoteEvent(FSTTestDoc("foo/bar", 20, @{@"a" : @"b"}, NO),
                                                   @[ @2 ], @[])];
 
   [self.localStore locallyWriteMutations:@[ FSTTestSetMutation(@"foo/bonk", @{@"a" : @"b"}) ]];
diff --git a/Firestore/Example/Tests/Local/FSTRemoteDocumentCacheTests.mm b/Firestore/Example/Tests/Local/FSTRemoteDocumentCacheTests.mm
index d056488..16b7185 100644
--- a/Firestore/Example/Tests/Local/FSTRemoteDocumentCacheTests.mm
+++ b/Firestore/Example/Tests/Local/FSTRemoteDocumentCacheTests.mm
@@ -25,10 +25,17 @@
 
 #import "Firestore/Example/Tests/Util/FSTHelpers.h"
 
+#include "Firestore/core/src/firebase/firestore/util/string_apple.h"
+#include "Firestore/core/test/firebase/firestore/testutil/testutil.h"
+#include "absl/strings/string_view.h"
+
+namespace testutil = firebase::firestore::testutil;
+namespace util = firebase::firestore::util;
+
 NS_ASSUME_NONNULL_BEGIN
 
-static NSString *const kDocPath = @"a/b";
-static NSString *const kLongDocPath = @"a/b/c/d/e/f";
+static const char *kDocPath = "a/b";
+static const char *kLongDocPath = "a/b/c/d/e/f";
 static const int kVersion = 42;
 
 @implementation FSTRemoteDocumentCacheTests {
@@ -49,7 +56,7 @@ static const int kVersion = 42;
 }
 
 // Helper for next two tests.
-- (void)setAndReadADocumentAtPath:(NSString *)path {
+- (void)setAndReadADocumentAtPath:(const absl::string_view)path {
   FSTDocument *written = [self setTestDocumentAtPath:path];
   FSTMaybeDocument *read = [self readEntryAtPath:path];
   XCTAssertEqualObjects(read, written);
@@ -107,15 +114,15 @@ static const int kVersion = 42;
 
   // TODO(rsgowman): This just verifies that we do a prefix scan against the
   // query path. We'll need more tests once we add index support.
-  [self setTestDocumentAtPath:@"a/1"];
-  [self setTestDocumentAtPath:@"b/1"];
-  [self setTestDocumentAtPath:@"b/2"];
-  [self setTestDocumentAtPath:@"c/1"];
+  [self setTestDocumentAtPath:"a/1"];
+  [self setTestDocumentAtPath:"b/1"];
+  [self setTestDocumentAtPath:"b/2"];
+  [self setTestDocumentAtPath:"c/1"];
 
   FSTQuery *query = FSTTestQuery("b");
   FSTDocumentDictionary *results = [self.remoteDocumentCache documentsMatchingQuery:query];
   NSArray *expected =
-      @[ FSTTestDoc(@"b/1", kVersion, _kDocData, NO), FSTTestDoc(@"b/2", kVersion, _kDocData, NO) ];
+      @[ FSTTestDoc("b/1", kVersion, _kDocData, NO), FSTTestDoc("b/2", kVersion, _kDocData, NO) ];
   XCTAssertEqual([results count], [expected count]);
   for (FSTDocument *doc in expected) {
     XCTAssertEqualObjects([results objectForKey:doc.key], doc);
@@ -124,7 +131,7 @@ static const int kVersion = 42;
 
 #pragma mark - Helpers
 
-- (FSTDocument *)setTestDocumentAtPath:(NSString *)path {
+- (FSTDocument *)setTestDocumentAtPath:(const absl::string_view)path {
   FSTDocument *doc = FSTTestDoc(path, kVersion, _kDocData, NO);
   [self addEntry:doc];
   return doc;
@@ -136,13 +143,13 @@ static const int kVersion = 42;
   [self.persistence commitGroup:group];
 }
 
-- (FSTMaybeDocument *_Nullable)readEntryAtPath:(NSString *)path {
-  return [self.remoteDocumentCache entryForKey:FSTTestDocKey(path)];
+- (FSTMaybeDocument *_Nullable)readEntryAtPath:(const absl::string_view)path {
+  return [self.remoteDocumentCache entryForKey:testutil::Key(path)];
 }
 
-- (void)removeEntryAtPath:(NSString *)path {
+- (void)removeEntryAtPath:(const absl::string_view)path {
   FSTWriteGroup *group = [self.persistence startGroupWithAction:@"removeEntryAtPath"];
-  [self.remoteDocumentCache removeEntryForKey:FSTTestDocKey(path) group:group];
+  [self.remoteDocumentCache removeEntryForKey:testutil::Key(path) group:group];
   [self.persistence commitGroup:group];
 }
 
diff --git a/Firestore/Example/Tests/Local/FSTRemoteDocumentChangeBufferTests.mm b/Firestore/Example/Tests/Local/FSTRemoteDocumentChangeBufferTests.mm
index 1970779..36d3661 100644
--- a/Firestore/Example/Tests/Local/FSTRemoteDocumentChangeBufferTests.mm
+++ b/Firestore/Example/Tests/Local/FSTRemoteDocumentChangeBufferTests.mm
@@ -47,7 +47,7 @@ NS_ASSUME_NONNULL_BEGIN
 
   // Add a couple initial items to the cache.
   FSTWriteGroup *group = [_db startGroupWithAction:@"Add initial docs."];
-  _kInitialADoc = FSTTestDoc(@"coll/a", 42, @{@"test" : @"data"}, NO);
+  _kInitialADoc = FSTTestDoc("coll/a", 42, @{@"test" : @"data"}, NO);
   [_remoteDocumentCache addEntry:_kInitialADoc group:group];
 
   _kInitialBDoc =
@@ -73,7 +73,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (void)testAddEntryAndReadItBack {
-  FSTMaybeDocument *newADoc = FSTTestDoc(@"coll/a", 43, @{@"new" : @"data"}, NO);
+  FSTMaybeDocument *newADoc = FSTTestDoc("coll/a", 43, @{@"new" : @"data"}, NO);
   [_remoteDocumentBuffer addEntry:newADoc];
   XCTAssertEqualObjects([_remoteDocumentBuffer entryForKey:FSTTestDocKey(@"coll/a")], newADoc);
 
@@ -83,7 +83,7 @@ NS_ASSUME_NONNULL_BEGIN
 }
 
 - (void)testApplyChanges {
-  FSTMaybeDocument *newADoc = FSTTestDoc(@"coll/a", 43, @{@"new" : @"data"}, NO);
+  FSTMaybeDocument *newADoc = FSTTestDoc("coll/a", 43, @{@"new" : @"data"}, NO);
   [_remoteDocumentBuffer addEntry:newADoc];
   XCTAssertEqualObjects([_remoteDocumentBuffer entryForKey:FSTTestDocKey(@"coll/a")], newADoc);