[8/8] tests/fetch: Test gitsm with LFS

diff --git a/lib/bb/tests/fetch.py b/lib/bb/tests/fetch.py
index a936af6fb..70a5eea22 100644
--- a/lib/bb/tests/fetch.py
+++ b/lib/bb/tests/fetch.py
@@ -20,6 +20,7 @@  import tarfile
 from bb.fetch2 import URI
 from bb.fetch2 import FetchMethod
 import bb
+import bb.utils
 from bb.tests.support.httpserver import HTTPService
 
 def skipIfNoNetwork():
@@ -27,6 +28,18 @@  def skipIfNoNetwork():
         return unittest.skip("network test")
     return lambda f: f
 
+
+@contextlib.contextmanager
+def hide_directory(directory):
+    """Hide the given directory and restore it after the context is left"""
+    temp_name = directory + ".bak"
+    os.rename(directory, temp_name)
+    try:
+        yield
+    finally:
+        os.rename(temp_name, directory)
+
+
 class TestTimeout(Exception):
     # Indicate to pytest that this is not a test suite
     __test__ = False
@@ -2293,12 +2306,18 @@  class GitLfsTest(FetcherTest):
         self.git_init(cwd=self.srcdir)
         self.commit_file('.gitattributes', '*.mp3 filter=lfs -text')
 
-    def commit_file(self, filename, content):
-        with open(os.path.join(self.srcdir, filename), "w") as f:
+    def commit(self, *, cwd=None):
+        cwd = cwd or self.srcdir
+        self.git(["commit", "-m", "Change"], cwd=cwd)
+        return self.git(["rev-parse", "HEAD"], cwd=cwd).strip()
+
+    def commit_file(self, filename, content, *, cwd=None):
+        cwd = cwd or self.srcdir
+
+        with open(os.path.join(cwd, filename), "w") as f:
             f.write(content)
-        self.git(["add", filename], cwd=self.srcdir)
-        self.git(["commit", "-m", "Change"], cwd=self.srcdir)
-        return self.git(["rev-parse", "HEAD"], cwd=self.srcdir).strip()
+        self.git(["add", filename], cwd=cwd)
+        return self.commit(cwd=cwd)
 
     def fetch(self, uri=None, download=True):
         uris = self.d.getVar('SRC_URI').split()
@@ -2318,26 +2337,69 @@  class GitLfsTest(FetcherTest):
         unpacked_lfs_file = os.path.join(self.d.getVar('WORKDIR'), 'git', "Cat_poster_1.jpg")
         return unpacked_lfs_file
 
+    @skipIfNoGitLFS()
+    def test_gitsm_lfs(self):
+        """Test that the gitsm fetcher caches objects stored via LFS"""
+        self.git(["lfs", "install", "--local"], cwd=self.srcdir)
+
+        def fetch_and_verify(revision, filename, content):
+            self.d.setVar('SRCREV', revision)
+            fetcher, ud = self.fetch()
+
+            with hide_directory(submoduledir), hide_directory(self.srcdir):
+                workdir = self.d.getVar('WORKDIR')
+                fetcher.unpack(workdir)
+
+                with open(os.path.join(workdir, "git", filename)) as f:
+                    self.assertEqual(f.read(), content)
+
+        # Create the git repository that will later be used as a submodule
+        submoduledir = self.tempdir + "/submodule"
+        bb.utils.mkdirhier(submoduledir)
+        self.git_init(submoduledir)
+        self.commit_file('.gitattributes', '*.mp3 filter=lfs -text', cwd=submoduledir)
+
+        submodule_commit_1 = self.commit_file("a.mp3", "submodule version 1", cwd=submoduledir)
+        _ = self.commit_file("a.mp3", "submodule version 2", cwd=submoduledir)
+
+        # Add the submodule to the repository at its current HEAD revision
+        self.git(["-c", "protocol.file.allow=always", "submodule", "add", submoduledir, "submodule"],
+                 cwd=self.srcdir)
+        base_commit_1 = self.commit()
+
+        # Let the submodule point at a different revision
+        self.git(["checkout", submodule_commit_1], self.srcdir + "/submodule")
+        self.git(["add", "submodule"], cwd=self.srcdir)
+        base_commit_2 = self.commit()
+
+        # Add a LFS file to the repository
+        base_commit_3 = self.commit_file("a.mp3", "version 1")
+        # Update the added LFS file
+        base_commit_4 = self.commit_file("a.mp3", "version 2")
+
+        self.d.setVar('SRC_URI', "gitsm://%s;protocol=file;lfs=1;branch=master" % self.srcdir)
+
+        # Verify that LFS objects referenced from submodules are fetched and checked out
+        fetch_and_verify(base_commit_1, "submodule/a.mp3", "submodule version 2")
+        # Verify that the repository inside the download cache of a submodile is extended with any
+        # additional LFS objects needed when checking out a different revision.
+        fetch_and_verify(base_commit_2, "submodule/a.mp3", "submodule version 1")
+        # Verify that LFS objects referenced from the base repository are fetched and checked out
+        fetch_and_verify(base_commit_3, "a.mp3", "version 1")
+        # Verify that the cached repository is extended with any additional LFS objects required
+        # when checking out a different revision.
+        fetch_and_verify(base_commit_4, "a.mp3", "version 2")
+
     @skipIfNoGitLFS()
     def test_fetch_lfs_on_srcrev_change(self):
         """Test if fetch downloads missing LFS objects when a different revision within an existing repository is requested"""
         self.git(["lfs", "install", "--local"], cwd=self.srcdir)
 
-        @contextlib.contextmanager
-        def hide_upstream_repository():
-            """Hide the upstream repository to make sure that git lfs cannot pull from it"""
-            temp_name = self.srcdir + ".bak"
-            os.rename(self.srcdir, temp_name)
-            try:
-                yield
-            finally:
-                os.rename(temp_name, self.srcdir)
-
         def fetch_and_verify(revision, filename, content):
             self.d.setVar('SRCREV', revision)
             fetcher, ud = self.fetch()
 
-            with hide_upstream_repository():
+            with hide_directory(self.srcdir):
                 workdir = self.d.getVar('WORKDIR')
                 fetcher.unpack(workdir)