Updated to Clang 3.5a.

Change-Id: I8127eb568f674c2e72635b639a3295381fe8af82
diff --git a/unittests/Basic/VirtualFileSystemTest.cpp b/unittests/Basic/VirtualFileSystemTest.cpp
new file mode 100644
index 0000000..40d2f16
--- /dev/null
+++ b/unittests/Basic/VirtualFileSystemTest.cpp
@@ -0,0 +1,582 @@
+//===- unittests/Basic/VirtualFileSystem.cpp ---------------- VFS tests ---===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Basic/VirtualFileSystem.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/Path.h"
+#include "llvm/Support/SourceMgr.h"
+#include "gtest/gtest.h"
+#include <map>
+using namespace clang;
+using namespace llvm;
+using llvm::sys::fs::UniqueID;
+
+namespace {
+class DummyFileSystem : public vfs::FileSystem {
+  int FSID;   // used to produce UniqueIDs
+  int FileID; // used to produce UniqueIDs
+  std::map<std::string, vfs::Status> FilesAndDirs;
+
+  static int getNextFSID() {
+    static int Count = 0;
+    return Count++;
+  }
+
+public:
+  DummyFileSystem() : FSID(getNextFSID()), FileID(0) {}
+
+  ErrorOr<vfs::Status> status(const Twine &Path) {
+    std::map<std::string, vfs::Status>::iterator I =
+        FilesAndDirs.find(Path.str());
+    if (I == FilesAndDirs.end())
+      return error_code(errc::no_such_file_or_directory, posix_category());
+    return I->second;
+  }
+  error_code openFileForRead(const Twine &Path,
+                             std::unique_ptr<vfs::File> &Result) {
+    llvm_unreachable("unimplemented");
+  }
+  error_code getBufferForFile(const Twine &Name,
+                              std::unique_ptr<MemoryBuffer> &Result,
+                              int64_t FileSize = -1,
+                              bool RequiresNullTerminator = true) {
+    llvm_unreachable("unimplemented");
+  }
+
+  void addEntry(StringRef Path, const vfs::Status &Status) {
+    FilesAndDirs[Path] = Status;
+  }
+
+  void addRegularFile(StringRef Path, sys::fs::perms Perms = sys::fs::all_all) {
+    vfs::Status S(Path, Path, UniqueID(FSID, FileID++), sys::TimeValue::now(),
+                  0, 0, 1024, sys::fs::file_type::regular_file, Perms);
+    addEntry(Path, S);
+  }
+
+  void addDirectory(StringRef Path, sys::fs::perms Perms = sys::fs::all_all) {
+    vfs::Status S(Path, Path, UniqueID(FSID, FileID++), sys::TimeValue::now(),
+                  0, 0, 0, sys::fs::file_type::directory_file, Perms);
+    addEntry(Path, S);
+  }
+
+  void addSymlink(StringRef Path) {
+    vfs::Status S(Path, Path, UniqueID(FSID, FileID++), sys::TimeValue::now(),
+                  0, 0, 0, sys::fs::file_type::symlink_file, sys::fs::all_all);
+    addEntry(Path, S);
+  }
+};
+} // end anonymous namespace
+
+TEST(VirtualFileSystemTest, StatusQueries) {
+  IntrusiveRefCntPtr<DummyFileSystem> D(new DummyFileSystem());
+  ErrorOr<vfs::Status> Status((error_code()));
+
+  D->addRegularFile("/foo");
+  Status = D->status("/foo");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_TRUE(Status->isStatusKnown());
+  EXPECT_FALSE(Status->isDirectory());
+  EXPECT_TRUE(Status->isRegularFile());
+  EXPECT_FALSE(Status->isSymlink());
+  EXPECT_FALSE(Status->isOther());
+  EXPECT_TRUE(Status->exists());
+
+  D->addDirectory("/bar");
+  Status = D->status("/bar");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_TRUE(Status->isStatusKnown());
+  EXPECT_TRUE(Status->isDirectory());
+  EXPECT_FALSE(Status->isRegularFile());
+  EXPECT_FALSE(Status->isSymlink());
+  EXPECT_FALSE(Status->isOther());
+  EXPECT_TRUE(Status->exists());
+
+  D->addSymlink("/baz");
+  Status = D->status("/baz");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_TRUE(Status->isStatusKnown());
+  EXPECT_FALSE(Status->isDirectory());
+  EXPECT_FALSE(Status->isRegularFile());
+  EXPECT_TRUE(Status->isSymlink());
+  EXPECT_FALSE(Status->isOther());
+  EXPECT_TRUE(Status->exists());
+
+  EXPECT_TRUE(Status->equivalent(*Status));
+  ErrorOr<vfs::Status> Status2 = D->status("/foo");
+  ASSERT_EQ(errc::success, Status2.getError());
+  EXPECT_FALSE(Status->equivalent(*Status2));
+}
+
+TEST(VirtualFileSystemTest, BaseOnlyOverlay) {
+  IntrusiveRefCntPtr<DummyFileSystem> D(new DummyFileSystem());
+  ErrorOr<vfs::Status> Status((error_code()));
+  EXPECT_FALSE(Status = D->status("/foo"));
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(new vfs::OverlayFileSystem(D));
+  EXPECT_FALSE(Status = O->status("/foo"));
+
+  D->addRegularFile("/foo");
+  Status = D->status("/foo");
+  EXPECT_EQ(errc::success, Status.getError());
+
+  ErrorOr<vfs::Status> Status2((error_code()));
+  Status2 = O->status("/foo");
+  EXPECT_EQ(errc::success, Status2.getError());
+  EXPECT_TRUE(Status->equivalent(*Status2));
+}
+
+TEST(VirtualFileSystemTest, OverlayFiles) {
+  IntrusiveRefCntPtr<DummyFileSystem> Base(new DummyFileSystem());
+  IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
+  IntrusiveRefCntPtr<DummyFileSystem> Top(new DummyFileSystem());
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Base));
+  O->pushOverlay(Middle);
+  O->pushOverlay(Top);
+
+  ErrorOr<vfs::Status> Status1((error_code())), Status2((error_code())),
+      Status3((error_code())), StatusB((error_code())), StatusM((error_code())),
+      StatusT((error_code()));
+
+  Base->addRegularFile("/foo");
+  StatusB = Base->status("/foo");
+  ASSERT_EQ(errc::success, StatusB.getError());
+  Status1 = O->status("/foo");
+  ASSERT_EQ(errc::success, Status1.getError());
+  Middle->addRegularFile("/foo");
+  StatusM = Middle->status("/foo");
+  ASSERT_EQ(errc::success, StatusM.getError());
+  Status2 = O->status("/foo");
+  ASSERT_EQ(errc::success, Status2.getError());
+  Top->addRegularFile("/foo");
+  StatusT = Top->status("/foo");
+  ASSERT_EQ(errc::success, StatusT.getError());
+  Status3 = O->status("/foo");
+  ASSERT_EQ(errc::success, Status3.getError());
+
+  EXPECT_TRUE(Status1->equivalent(*StatusB));
+  EXPECT_TRUE(Status2->equivalent(*StatusM));
+  EXPECT_TRUE(Status3->equivalent(*StatusT));
+
+  EXPECT_FALSE(Status1->equivalent(*Status2));
+  EXPECT_FALSE(Status2->equivalent(*Status3));
+  EXPECT_FALSE(Status1->equivalent(*Status3));
+}
+
+TEST(VirtualFileSystemTest, OverlayDirsNonMerged) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(Upper);
+
+  Lower->addDirectory("/lower-only");
+  Upper->addDirectory("/upper-only");
+
+  // non-merged paths should be the same
+  ErrorOr<vfs::Status> Status1 = Lower->status("/lower-only");
+  ASSERT_EQ(errc::success, Status1.getError());
+  ErrorOr<vfs::Status> Status2 = O->status("/lower-only");
+  ASSERT_EQ(errc::success, Status2.getError());
+  EXPECT_TRUE(Status1->equivalent(*Status2));
+
+  Status1 = Upper->status("/upper-only");
+  ASSERT_EQ(errc::success, Status1.getError());
+  Status2 = O->status("/upper-only");
+  ASSERT_EQ(errc::success, Status2.getError());
+  EXPECT_TRUE(Status1->equivalent(*Status2));
+}
+
+TEST(VirtualFileSystemTest, MergedDirPermissions) {
+  // merged directories get the permissions of the upper dir
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(Upper);
+
+  ErrorOr<vfs::Status> Status((error_code()));
+  Lower->addDirectory("/both", sys::fs::owner_read);
+  Upper->addDirectory("/both", sys::fs::owner_all | sys::fs::group_read);
+  Status = O->status("/both");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_EQ(0740, Status->getPermissions());
+
+  // permissions (as usual) are not recursively applied
+  Lower->addRegularFile("/both/foo", sys::fs::owner_read);
+  Upper->addRegularFile("/both/bar", sys::fs::owner_write);
+  Status = O->status("/both/foo");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_EQ(0400, Status->getPermissions());
+  Status = O->status("/both/bar");
+  ASSERT_EQ(errc::success, Status.getError());
+  EXPECT_EQ(0200, Status->getPermissions());
+}
+
+// NOTE: in the tests below, we use '//root/' as our root directory, since it is
+// a legal *absolute* path on Windows as well as *nix.
+class VFSFromYAMLTest : public ::testing::Test {
+public:
+  int NumDiagnostics;
+
+  void SetUp() {
+    NumDiagnostics = 0;
+  }
+
+  static void CountingDiagHandler(const SMDiagnostic &, void *Context) {
+    VFSFromYAMLTest *Test = static_cast<VFSFromYAMLTest *>(Context);
+    ++Test->NumDiagnostics;
+  }
+
+  IntrusiveRefCntPtr<vfs::FileSystem>
+  getFromYAMLRawString(StringRef Content,
+                       IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS) {
+    MemoryBuffer *Buffer = MemoryBuffer::getMemBuffer(Content);
+    return getVFSFromYAML(Buffer, CountingDiagHandler, this, ExternalFS);
+  }
+
+  IntrusiveRefCntPtr<vfs::FileSystem> getFromYAMLString(
+      StringRef Content,
+      IntrusiveRefCntPtr<vfs::FileSystem> ExternalFS = new DummyFileSystem()) {
+    std::string VersionPlusContent("{\n  'version':0,\n");
+    VersionPlusContent += Content.slice(Content.find('{') + 1, StringRef::npos);
+    return getFromYAMLRawString(VersionPlusContent, ExternalFS);
+  }
+};
+
+TEST_F(VFSFromYAMLTest, BasicVFSFromYAML) {
+  IntrusiveRefCntPtr<vfs::FileSystem> FS;
+  FS = getFromYAMLString("");
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("[]");
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("'string'");
+  EXPECT_EQ(NULL, FS.getPtr());
+  EXPECT_EQ(3, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, MappedFiles) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/foo/bar/a");
+  IntrusiveRefCntPtr<vfs::FileSystem> FS =
+      getFromYAMLString("{ 'roots': [\n"
+                        "{\n"
+                        "  'type': 'directory',\n"
+                        "  'name': '//root/',\n"
+                        "  'contents': [ {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'file1',\n"
+                        "                  'external-contents': '//root/foo/bar/a'\n"
+                        "                },\n"
+                        "                {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'file2',\n"
+                        "                  'external-contents': '//root/foo/b'\n"
+                        "                }\n"
+                        "              ]\n"
+                        "}\n"
+                        "]\n"
+                        "}",
+                        Lower);
+  ASSERT_TRUE(FS.getPtr() != NULL);
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(FS);
+
+  // file
+  ErrorOr<vfs::Status> S = O->status("//root/file1");
+  ASSERT_EQ(errc::success, S.getError());
+  EXPECT_EQ("//root/foo/bar/a", S->getName());
+
+  ErrorOr<vfs::Status> SLower = O->status("//root/foo/bar/a");
+  EXPECT_EQ("//root/foo/bar/a", SLower->getName());
+  EXPECT_TRUE(S->equivalent(*SLower));
+
+  // directory
+  S = O->status("//root/");
+  ASSERT_EQ(errc::success, S.getError());
+  EXPECT_TRUE(S->isDirectory());
+  EXPECT_TRUE(S->equivalent(*O->status("//root/"))); // non-volatile UniqueID
+
+  // broken mapping
+  EXPECT_EQ(errc::no_such_file_or_directory, O->status("//root/file2").getError());
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, CaseInsensitive) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/foo/bar/a");
+  IntrusiveRefCntPtr<vfs::FileSystem> FS =
+      getFromYAMLString("{ 'case-sensitive': 'false',\n"
+                        "  'roots': [\n"
+                        "{\n"
+                        "  'type': 'directory',\n"
+                        "  'name': '//root/',\n"
+                        "  'contents': [ {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'XX',\n"
+                        "                  'external-contents': '//root/foo/bar/a'\n"
+                        "                }\n"
+                        "              ]\n"
+                        "}]}",
+                        Lower);
+  ASSERT_TRUE(FS.getPtr() != NULL);
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(FS);
+
+  ErrorOr<vfs::Status> S = O->status("//root/XX");
+  ASSERT_EQ(errc::success, S.getError());
+
+  ErrorOr<vfs::Status> SS = O->status("//root/xx");
+  ASSERT_EQ(errc::success, SS.getError());
+  EXPECT_TRUE(S->equivalent(*SS));
+  SS = O->status("//root/xX");
+  EXPECT_TRUE(S->equivalent(*SS));
+  SS = O->status("//root/Xx");
+  EXPECT_TRUE(S->equivalent(*SS));
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, CaseSensitive) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/foo/bar/a");
+  IntrusiveRefCntPtr<vfs::FileSystem> FS =
+      getFromYAMLString("{ 'case-sensitive': 'true',\n"
+                        "  'roots': [\n"
+                        "{\n"
+                        "  'type': 'directory',\n"
+                        "  'name': '//root/',\n"
+                        "  'contents': [ {\n"
+                        "                  'type': 'file',\n"
+                        "                  'name': 'XX',\n"
+                        "                  'external-contents': '//root/foo/bar/a'\n"
+                        "                }\n"
+                        "              ]\n"
+                        "}]}",
+                        Lower);
+  ASSERT_TRUE(FS.getPtr() != NULL);
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(FS);
+
+  ErrorOr<vfs::Status> SS = O->status("//root/xx");
+  EXPECT_EQ(errc::no_such_file_or_directory, SS.getError());
+  SS = O->status("//root/xX");
+  EXPECT_EQ(errc::no_such_file_or_directory, SS.getError());
+  SS = O->status("//root/Xx");
+  EXPECT_EQ(errc::no_such_file_or_directory, SS.getError());
+  EXPECT_EQ(0, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, IllegalVFSFile) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+
+  // invalid YAML at top-level
+  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString("{]", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  // invalid YAML in roots
+  FS = getFromYAMLString("{ 'roots':[}", Lower);
+  // invalid YAML in directory
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'name': 'foo', 'type': 'directory', 'contents': [}",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // invalid configuration
+  FS = getFromYAMLString("{ 'knobular': 'true', 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("{ 'case-sensitive': 'maybe', 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // invalid roots
+  FS = getFromYAMLString("{ 'roots':'' }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("{ 'roots':{} }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // invalid entries
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'other', 'name': 'me', 'contents': '' }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("{ 'roots':[ { 'type': 'file', 'name': [], "
+                         "'external-contents': 'other' }",
+                         Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'file', 'name': 'me', 'external-contents': [] }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'file', 'name': 'me', 'external-contents': {} }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'directory', 'name': 'me', 'contents': {} }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'directory', 'name': 'me', 'contents': '' }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'thingy': 'directory', 'name': 'me', 'contents': [] }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // missing mandatory fields
+  FS = getFromYAMLString("{ 'roots':[ { 'type': 'file', 'name': 'me' }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'roots':[ { 'type': 'file', 'external-contents': 'other' }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString("{ 'roots':[ { 'name': 'me', 'contents': [] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // duplicate keys
+  FS = getFromYAMLString("{ 'roots':[], 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLString(
+      "{ 'case-sensitive':'true', 'case-sensitive':'true', 'roots':[] }",
+      Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS =
+      getFromYAMLString("{ 'roots':[{'name':'me', 'name':'you', 'type':'file', "
+                        "'external-contents':'blah' } ] }",
+                        Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // missing version
+  FS = getFromYAMLRawString("{ 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+
+  // bad version number
+  FS = getFromYAMLRawString("{ 'version':'foo', 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLRawString("{ 'version':-1, 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  FS = getFromYAMLRawString("{ 'version':100000, 'roots':[] }", Lower);
+  EXPECT_EQ(NULL, FS.getPtr());
+  EXPECT_EQ(24, NumDiagnostics);
+}
+
+TEST_F(VFSFromYAMLTest, UseExternalName) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/external/file");
+
+  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
+      "{ 'roots': [\n"
+      "  { 'type': 'file', 'name': '//root/A',\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  },\n"
+      "  { 'type': 'file', 'name': '//root/B',\n"
+      "    'use-external-name': true,\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  },\n"
+      "  { 'type': 'file', 'name': '//root/C',\n"
+      "    'use-external-name': false,\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  }\n"
+      "] }", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+
+  // default true
+  EXPECT_EQ("//root/external/file", FS->status("//root/A")->getName());
+  // explicit
+  EXPECT_EQ("//root/external/file", FS->status("//root/B")->getName());
+  EXPECT_EQ("//root/C", FS->status("//root/C")->getName());
+
+  // global configuration
+  FS = getFromYAMLString(
+      "{ 'use-external-names': false,\n"
+      "  'roots': [\n"
+      "  { 'type': 'file', 'name': '//root/A',\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  },\n"
+      "  { 'type': 'file', 'name': '//root/B',\n"
+      "    'use-external-name': true,\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  },\n"
+      "  { 'type': 'file', 'name': '//root/C',\n"
+      "    'use-external-name': false,\n"
+      "    'external-contents': '//root/external/file'\n"
+      "  }\n"
+      "] }", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+
+  // default
+  EXPECT_EQ("//root/A", FS->status("//root/A")->getName());
+  // explicit
+  EXPECT_EQ("//root/external/file", FS->status("//root/B")->getName());
+  EXPECT_EQ("//root/C", FS->status("//root/C")->getName());
+}
+
+TEST_F(VFSFromYAMLTest, MultiComponentPath) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/other");
+
+  // file in roots
+  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
+      "{ 'roots': [\n"
+      "  { 'type': 'file', 'name': '//root/path/to/file',\n"
+      "    'external-contents': '//root/other' }]\n"
+      "}", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to/file").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/").getError());
+
+  // at the start
+  FS = getFromYAMLString(
+      "{ 'roots': [\n"
+      "  { 'type': 'directory', 'name': '//root/path/to',\n"
+      "    'contents': [ { 'type': 'file', 'name': 'file',\n"
+      "                    'external-contents': '//root/other' }]}]\n"
+      "}", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to/file").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/").getError());
+
+  // at the end
+  FS = getFromYAMLString(
+      "{ 'roots': [\n"
+      "  { 'type': 'directory', 'name': '//root/',\n"
+      "    'contents': [ { 'type': 'file', 'name': 'path/to/file',\n"
+      "                    'external-contents': '//root/other' }]}]\n"
+      "}", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to/file").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/").getError());
+}
+
+TEST_F(VFSFromYAMLTest, TrailingSlashes) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("//root/other");
+
+  // file in roots
+  IntrusiveRefCntPtr<vfs::FileSystem> FS = getFromYAMLString(
+      "{ 'roots': [\n"
+      "  { 'type': 'directory', 'name': '//root/path/to////',\n"
+      "    'contents': [ { 'type': 'file', 'name': 'file',\n"
+      "                    'external-contents': '//root/other' }]}]\n"
+      "}", Lower);
+  ASSERT_TRUE(NULL != FS.getPtr());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to/file").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path/to").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/path").getError());
+  EXPECT_EQ(errc::success, FS->status("//root/").getError());
+}