thodg/libgit2

diff --git a/include/git2/worktree.h b/include/git2/worktree.h
index cad1284..4c4f928 100644
--- a/include/git2/worktree.h
+++ b/include/git2/worktree.h
@@ -44,6 +44,18 @@ GIT_EXTERN(int) git_worktree_list(git_strarray *out, git_repository *repo);
 GIT_EXTERN(int) git_worktree_lookup(git_worktree **out, git_repository *repo, const char *name);
 
 /**
+ * Open a worktree of a given repository
+ *
+ * If a repository is not the main tree but a worktree, this
+ * function will look up the worktree inside the parent
+ * repository and create a new `git_worktree` structure.
+ *
+ * @param out Out-pointer for the newly allocated worktree
+ * @param repo Repository to look up worktree for
+ */
+GIT_EXTERN(int) git_worktree_open_from_repository(git_worktree **out, git_repository *repo);
+
+/**
  * Free a previously allocated worktree
  *
  * @param wt worktree handle to close. If NULL nothing occurs.
diff --git a/src/refdb_fs.c b/src/refdb_fs.c
index 450b3f3..b325d27 100644
--- a/src/refdb_fs.c
+++ b/src/refdb_fs.c
@@ -739,6 +739,7 @@ static int loose_lock(git_filebuf *file, refdb_fs_backend *backend, const char *
 {
 	int error, filebuf_flags;
 	git_buf ref_path = GIT_BUF_INIT;
+	const char *basedir;
 
 	assert(file && backend && name);
 
@@ -747,13 +748,18 @@ static int loose_lock(git_filebuf *file, refdb_fs_backend *backend, const char *
 		return GIT_EINVALIDSPEC;
 	}
 
+	if (is_per_worktree_ref(name))
+		basedir = backend->gitpath;
+	else
+		basedir = backend->commonpath;
+
 	/* Remove a possibly existing empty directory hierarchy
 	 * which name would collide with the reference name
 	 */
-	if ((error = git_futils_rmdir_r(name, backend->gitpath, GIT_RMDIR_SKIP_NONEMPTY)) < 0)
+	if ((error = git_futils_rmdir_r(name, basedir, GIT_RMDIR_SKIP_NONEMPTY)) < 0)
 		return error;
 
-	if (git_buf_joinpath(&ref_path, backend->gitpath, name) < 0)
+	if (git_buf_joinpath(&ref_path, basedir, name) < 0)
 		return -1;
 
 	filebuf_flags = GIT_FILEBUF_FORCE;
diff --git a/src/submodule.c b/src/submodule.c
index 191cdf3..ddd4b06 100644
--- a/src/submodule.c
+++ b/src/submodule.c
@@ -22,6 +22,7 @@
 #include "iterator.h"
 #include "path.h"
 #include "index.h"
+#include "worktree.h"
 
 #define GIT_MODULES_FILE ".gitmodules"
 
@@ -2038,17 +2039,28 @@ static int lookup_default_remote(git_remote **remote, git_repository *repo)
 static int get_url_base(git_buf *url, git_repository *repo)
 {
 	int error;
+	git_worktree *wt = NULL;
 	git_remote *remote = NULL;
 
-	if (!(error = lookup_default_remote(&remote, repo))) {
+	if ((error = lookup_default_remote(&remote, repo)) == 0) {
 		error = git_buf_sets(url, git_remote_url(remote));
-		git_remote_free(remote);
-	}
-	else if (error == GIT_ENOTFOUND) {
-		/* if repository does not have a default remote, use workdir instead */
+		goto out;
+	} else if (error != GIT_ENOTFOUND)
+		goto out;
+	else
 		giterr_clear();
+
+	/* if repository does not have a default remote, use workdir instead */
+	if (git_repository_is_worktree(repo)) {
+		if ((error = git_worktree_open_from_repository(&wt, repo)) < 0)
+			goto out;
+		error = git_buf_sets(url, wt->parent_path);
+	} else
 		error = git_buf_sets(url, git_repository_workdir(repo));
-	}
+
+out:
+	git_remote_free(remote);
+	git_worktree_free(wt);
 
 	return error;
 }
diff --git a/src/worktree.c b/src/worktree.c
index 5abc989..393a088 100644
--- a/src/worktree.c
+++ b/src/worktree.c
@@ -14,11 +14,20 @@
 #include "repository.h"
 #include "worktree.h"
 
-static bool is_worktree_dir(git_buf *dir)
+static bool is_worktree_dir(const char *dir)
 {
-	return git_path_contains_file(dir, "commondir")
-		&& git_path_contains_file(dir, "gitdir")
-		&& git_path_contains_file(dir, "HEAD");
+	git_buf buf = GIT_BUF_INIT;
+	int error;
+
+	if (git_buf_sets(&buf, dir) < 0)
+		return -1;
+
+	error = git_path_contains_file(&buf, "commondir")
+		&& git_path_contains_file(&buf, "gitdir")
+		&& git_path_contains_file(&buf, "HEAD");
+
+	git_buf_free(&buf);
+	return error;
 }
 
 int git_worktree_list(git_strarray *wts, git_repository *repo)
@@ -47,7 +56,7 @@ int git_worktree_list(git_strarray *wts, git_repository *repo)
 		git_buf_truncate(&path, len);
 		git_buf_puts(&path, worktree);
 
-		if (!is_worktree_dir(&path)) {
+		if (!is_worktree_dir(path.ptr)) {
 			git_vector_remove(&worktrees, i);
 			git__free(worktree);
 		}
@@ -112,6 +121,46 @@ out:
 	return err;
 }
 
+static int open_worktree_dir(git_worktree **out, const char *parent, const char *dir, const char *name)
+{
+	git_buf gitdir = GIT_BUF_INIT;
+	git_worktree *wt = NULL;
+	int error = 0;
+
+	if (!is_worktree_dir(dir)) {
+		error = -1;
+		goto out;
+	}
+
+	if ((wt = git__calloc(1, sizeof(struct git_repository))) == NULL) {
+		error = -1;
+		goto out;
+	}
+
+	if ((wt->name = git__strdup(name)) == NULL
+	    || (wt->commondir_path = git_worktree__read_link(dir, "commondir")) == NULL
+	    || (wt->gitlink_path = git_worktree__read_link(dir, "gitdir")) == NULL
+	    || (wt->parent_path = git__strdup(parent)) == NULL) {
+		error = -1;
+		goto out;
+	}
+
+	if ((error = git_path_prettify_dir(&gitdir, dir, NULL)) < 0)
+		goto out;
+	wt->gitdir_path = git_buf_detach(&gitdir);
+
+	wt->locked = !!git_worktree_is_locked(NULL, wt);
+
+	*out = wt;
+
+out:
+	if (error)
+		git_worktree_free(wt);
+	git_buf_free(&gitdir);
+
+	return error;
+}
+
 int git_worktree_lookup(git_worktree **out, git_repository *repo, const char *name)
 {
 	git_buf path = GIT_BUF_INIT;
@@ -125,33 +174,47 @@ int git_worktree_lookup(git_worktree **out, git_repository *repo, const char *na
 	if ((error = git_buf_printf(&path, "%s/worktrees/%s", repo->commondir, name)) < 0)
 		goto out;
 
-	if (!is_worktree_dir(&path)) {
-		error = -1;
+	if ((error = (open_worktree_dir(out, git_repository_workdir(repo), path.ptr, name))) < 0)
 		goto out;
-	}
 
-	if ((wt = git__malloc(sizeof(struct git_repository))) == NULL) {
+out:
+	git_buf_free(&path);
+
+	if (error)
+		git_worktree_free(wt);
+
+	return error;
+}
+
+int git_worktree_open_from_repository(git_worktree **out, git_repository *repo)
+{
+	git_buf parent = GIT_BUF_INIT;
+	const char *gitdir, *commondir;
+	char *name = NULL;
+	int error = 0;
+
+	if (!git_repository_is_worktree(repo)) {
+		giterr_set(GITERR_WORKTREE, "cannot open worktree of a non-worktree repo");
 		error = -1;
 		goto out;
 	}
 
-	if ((wt->name = git__strdup(name)) == NULL
-	    || (wt->commondir_path = git_worktree__read_link(path.ptr, "commondir")) == NULL
-	    || (wt->gitlink_path = git_worktree__read_link(path.ptr, "gitdir")) == NULL
-	    || (wt->parent_path = git__strdup(git_repository_path(repo))) == NULL) {
-		error = -1;
+	gitdir = git_repository_path(repo);
+	commondir = git_repository_commondir(repo);
+
+	if ((error = git_path_prettify_dir(&parent, "..", commondir)) < 0)
 		goto out;
-	}
-	wt->gitdir_path = git_buf_detach(&path);
-	wt->locked = !!git_worktree_is_locked(NULL, wt);
 
-	(*out) = wt;
+	/* The name is defined by the last component in '.git/worktree/%s' */
+	name = git_path_basename(gitdir);
 
-out:
-	git_buf_free(&path);
+	if ((error = open_worktree_dir(out, parent.ptr, gitdir, name)) < 0)
+		goto out;
 
+out:
 	if (error)
-		git_worktree_free(wt);
+		free(name);
+	git_buf_free(&parent);
 
 	return error;
 }
@@ -177,7 +240,7 @@ int git_worktree_validate(const git_worktree *wt)
 	assert(wt);
 
 	git_buf_puts(&buf, wt->gitdir_path);
-	if (!is_worktree_dir(&buf)) {
+	if (!is_worktree_dir(buf.ptr)) {
 		giterr_set(GITERR_WORKTREE,
 			"Worktree gitdir ('%s') is not valid",
 			wt->gitlink_path);
@@ -209,7 +272,7 @@ out:
 
 int git_worktree_add(git_worktree **out, git_repository *repo, const char *name, const char *worktree)
 {
-	git_buf path = GIT_BUF_INIT, buf = GIT_BUF_INIT;
+	git_buf gitdir = GIT_BUF_INIT, wddir = GIT_BUF_INIT, buf = GIT_BUF_INIT;
 	git_reference *ref = NULL, *head = NULL;
 	git_commit *commit = NULL;
 	git_repository *wt = NULL;
@@ -220,35 +283,39 @@ int git_worktree_add(git_worktree **out, git_repository *repo, const char *name,
 
 	*out = NULL;
 
-	/* Create worktree related files in commondir */
-	if ((err = git_buf_joinpath(&path, repo->commondir, "worktrees")) < 0)
+	/* Create gitdir directory ".git/worktrees/<name>" */
+	if ((err = git_buf_joinpath(&gitdir, repo->commondir, "worktrees")) < 0)
 		goto out;
-	if (!git_path_exists(path.ptr))
-		if ((err = git_futils_mkdir(path.ptr, 0755, GIT_MKDIR_EXCL)) < 0)
+	if (!git_path_exists(gitdir.ptr))
+		if ((err = git_futils_mkdir(gitdir.ptr, 0755, GIT_MKDIR_EXCL)) < 0)
 			goto out;
-	if ((err = git_buf_joinpath(&path, path.ptr, name)) < 0)
+	if ((err = git_buf_joinpath(&gitdir, gitdir.ptr, name)) < 0)
+		goto out;
+	if ((err = git_futils_mkdir(gitdir.ptr, 0755, GIT_MKDIR_EXCL)) < 0)
 		goto out;
-	if ((err = git_futils_mkdir(path.ptr, 0755, GIT_MKDIR_EXCL)) < 0)
+	if ((err = git_path_prettify_dir(&gitdir, gitdir.ptr, NULL)) < 0)
 		goto out;
 
 	/* Create worktree work dir */
 	if ((err = git_futils_mkdir(worktree, 0755, GIT_MKDIR_EXCL)) < 0)
 		goto out;
+	if ((err = git_path_prettify_dir(&wddir, worktree, NULL)) < 0)
+		goto out;
 
 	/* Create worktree .git file */
-	if ((err = git_buf_printf(&buf, "gitdir: %s\n", path.ptr)) < 0)
+	if ((err = git_buf_printf(&buf, "gitdir: %s\n", gitdir.ptr)) < 0)
 		goto out;
-	if ((err = write_wtfile(worktree, ".git", &buf)) < 0)
+	if ((err = write_wtfile(wddir.ptr, ".git", &buf)) < 0)
 		goto out;
 
-	/* Create commondir files */
-	if ((err = git_buf_sets(&buf, repo->commondir)) < 0
+	/* Create gitdir files */
+	if ((err = git_path_prettify_dir(&buf, repo->commondir, NULL) < 0)
 	    || (err = git_buf_putc(&buf, '\n')) < 0
-	    || (err = write_wtfile(path.ptr, "commondir", &buf)) < 0)
+	    || (err = write_wtfile(gitdir.ptr, "commondir", &buf)) < 0)
 		goto out;
-	if ((err = git_buf_joinpath(&buf, worktree, ".git")) < 0
+	if ((err = git_buf_joinpath(&buf, wddir.ptr, ".git")) < 0
 	    || (err = git_buf_putc(&buf, '\n')) < 0
-	    || (err = write_wtfile(path.ptr, "gitdir", &buf)) < 0)
+	    || (err = write_wtfile(gitdir.ptr, "gitdir", &buf)) < 0)
 		goto out;
 
 	/* Create new branch */
@@ -260,9 +327,9 @@ int git_worktree_add(git_worktree **out, git_repository *repo, const char *name,
 		goto out;
 
 	/* Set worktree's HEAD */
-	if ((err = git_repository_create_head(path.ptr, name)) < 0)
+	if ((err = git_repository_create_head(gitdir.ptr, git_reference_name(ref))) < 0)
 		goto out;
-	if ((err = git_repository_open(&wt, worktree)) < 0)
+	if ((err = git_repository_open(&wt, wddir.ptr)) < 0)
 		goto out;
 
 	/* Checkout worktree's HEAD */
@@ -275,7 +342,8 @@ int git_worktree_add(git_worktree **out, git_repository *repo, const char *name,
 		goto out;
 
 out:
-	git_buf_free(&path);
+	git_buf_free(&gitdir);
+	git_buf_free(&wddir);
 	git_buf_free(&buf);
 	git_reference_free(ref);
 	git_reference_free(head);
@@ -394,7 +462,7 @@ int git_worktree_prune(git_worktree *wt, unsigned flags)
 	}
 
 	/* Delete gitdir in parent repository */
-	if ((err = git_buf_printf(&path, "%s/worktrees/%s", wt->parent_path, wt->name)) < 0)
+	if ((err = git_buf_printf(&path, "%s/worktrees/%s", wt->commondir_path, wt->name)) < 0)
 		goto out;
 	if (!git_path_exists(path.ptr))
 	{
diff --git a/src/worktree.h b/src/worktree.h
index b8e5279..57c2e65 100644
--- a/src/worktree.h
+++ b/src/worktree.h
@@ -24,7 +24,7 @@ struct git_worktree {
 	/* Path to the common directory contained in the parent
 	 * repository */
 	char *commondir_path;
-	/* Path to the parent's .git directory */
+	/* Path to the parent's working directory */
 	char *parent_path;
 
 	int locked:1;
diff --git a/tests/resources/submodules/testrepo/.gitted/config b/tests/resources/submodules/testrepo/.gitted/config
index d6dcad1..8e55711 100644
--- a/tests/resources/submodules/testrepo/.gitted/config
+++ b/tests/resources/submodules/testrepo/.gitted/config
@@ -4,9 +4,6 @@
 	bare = false
 	logallrefupdates = true
 	ignorecase = true
-[remote "origin"]
-	fetch = +refs/heads/*:refs/remotes/origin/*
-	url = /Users/rb/src/libgit2/tests/resources/testrepo.git
 [branch "master"]
 	remote = origin
 	merge = refs/heads/master
diff --git a/tests/worktree/open.c b/tests/worktree/open.c
index bdc8bcf..74b9007 100644
--- a/tests/worktree/open.c
+++ b/tests/worktree/open.c
@@ -1,13 +1,14 @@
 #include "clar_libgit2.h"
 #include "repository.h"
+#include "worktree.h"
 #include "worktree_helpers.h"
 
-#define WORKTREE_PARENT "submodules-worktree-parent"
-#define WORKTREE_CHILD "submodules-worktree-child"
-
 #define COMMON_REPO "testrepo"
 #define WORKTREE_REPO "testrepo-worktree"
 
+static worktree_fixture fixture =
+	WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
+
 static void assert_worktree_valid(git_repository *wt, const char *parentdir, const char *wtdir)
 {
 	git_buf path = GIT_BUF_INIT;
@@ -34,56 +35,46 @@ static void assert_worktree_valid(git_repository *wt, const char *parentdir, con
 	git_buf_free(&path);
 }
 
-void test_worktree_open__repository(void)
+void test_worktree_open__initialize(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
 	setup_fixture_worktree(&fixture);
+}
 
-	assert_worktree_valid(fixture.worktree, COMMON_REPO, WORKTREE_REPO);
-
+void test_worktree_open__cleanup(void)
+{
 	cleanup_fixture_worktree(&fixture);
 }
 
+void test_worktree_open__repository(void)
+{
+	assert_worktree_valid(fixture.worktree, COMMON_REPO, WORKTREE_REPO);
+}
+
 void test_worktree_open__repository_through_workdir(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
 	git_repository *wt;
 
-	setup_fixture_worktree(&fixture);
-
 	cl_git_pass(git_repository_open(&wt, WORKTREE_REPO));
 	assert_worktree_valid(wt, COMMON_REPO, WORKTREE_REPO);
 
 	git_repository_free(wt);
-	cleanup_fixture_worktree(&fixture);
 }
 
 void test_worktree_open__repository_through_gitlink(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
 	git_repository *wt;
 
-	setup_fixture_worktree(&fixture);
-
 	cl_git_pass(git_repository_open(&wt, WORKTREE_REPO "/.git"));
 	assert_worktree_valid(wt, COMMON_REPO, WORKTREE_REPO);
 
 	git_repository_free(wt);
-	cleanup_fixture_worktree(&fixture);
 }
 
 void test_worktree_open__repository_through_gitdir(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
 	git_buf gitdir_path = GIT_BUF_INIT;
 	git_repository *wt;
 
-	setup_fixture_worktree(&fixture);
-
 	cl_git_pass(git_buf_joinpath(&gitdir_path, COMMON_REPO, ".git"));
 	cl_git_pass(git_buf_joinpath(&gitdir_path, gitdir_path.ptr, "worktrees"));
 	cl_git_pass(git_buf_joinpath(&gitdir_path, gitdir_path.ptr, "testrepo-worktree"));
@@ -93,18 +84,13 @@ void test_worktree_open__repository_through_gitdir(void)
 
 	git_buf_free(&gitdir_path);
 	git_repository_free(wt);
-	cleanup_fixture_worktree(&fixture);
 }
 
 void test_worktree_open__open_discovered_worktree(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
 	git_buf path = GIT_BUF_INIT;
 	git_repository *repo;
 
-	setup_fixture_worktree(&fixture);
-
 	cl_git_pass(git_repository_discover(&path,
 		git_repository_workdir(fixture.worktree), false, NULL));
 	cl_git_pass(git_repository_open(&repo, path.ptr));
@@ -113,13 +99,14 @@ void test_worktree_open__open_discovered_worktree(void)
 
 	git_buf_free(&path);
 	git_repository_free(repo);
-	cleanup_fixture_worktree(&fixture);
 }
 
 void test_worktree_open__repository_with_nonexistent_parent(void)
 {
 	git_repository *repo;
 
+	cleanup_fixture_worktree(&fixture);
+
 	cl_fixture_sandbox(WORKTREE_REPO);
 	cl_git_pass(p_chdir(WORKTREE_REPO));
 	cl_git_pass(cl_rename(".gitted", ".git"));
@@ -130,65 +117,27 @@ void test_worktree_open__repository_with_nonexistent_parent(void)
 	cl_fixture_cleanup(WORKTREE_REPO);
 }
 
-void test_worktree_open__submodule_worktree_parent(void)
+void test_worktree_open__open_from_repository(void)
 {
-	worktree_fixture fixture =
-		WORKTREE_FIXTURE_INIT("submodules", WORKTREE_PARENT);
-	setup_fixture_worktree(&fixture);
-
-	cl_assert(git_repository_path(fixture.worktree) != NULL);
-	cl_assert(git_repository_workdir(fixture.worktree) != NULL);
+	git_worktree *opened, *lookedup;
 
-	cl_assert(!fixture.repo->is_worktree);
-	cl_assert(fixture.worktree->is_worktree);
+	cl_git_pass(git_worktree_open_from_repository(&opened, fixture.worktree));
+	cl_git_pass(git_worktree_lookup(&lookedup, fixture.repo, WORKTREE_REPO));
 
-	cleanup_fixture_worktree(&fixture);
-}
+	cl_assert_equal_s(opened->name, lookedup->name);
+	cl_assert_equal_s(opened->gitdir_path, lookedup->gitdir_path);
+	cl_assert_equal_s(opened->gitlink_path, lookedup->gitlink_path);
+	cl_assert_equal_s(opened->parent_path, lookedup->parent_path);
+	cl_assert_equal_s(opened->commondir_path, lookedup->commondir_path);
+	cl_assert_equal_i(opened->locked, lookedup->locked);
 
-void test_worktree_open__submodule_worktree_child(void)
-{
-	worktree_fixture parent_fixture =
-		WORKTREE_FIXTURE_INIT("submodules", WORKTREE_PARENT);
-	worktree_fixture child_fixture =
-		WORKTREE_FIXTURE_INIT(NULL, WORKTREE_CHILD);
-
-	setup_fixture_worktree(&parent_fixture);
-	cl_git_pass(p_rename(
-		"submodules/testrepo/.gitted",
-		"submodules/testrepo/.git"));
-	setup_fixture_worktree(&child_fixture);
-
-	cl_assert(!parent_fixture.repo->is_worktree);
-	cl_assert(parent_fixture.worktree->is_worktree);
-	cl_assert(child_fixture.worktree->is_worktree);
-
-	cleanup_fixture_worktree(&child_fixture);
-	cleanup_fixture_worktree(&parent_fixture);
+	git_worktree_free(opened);
+	git_worktree_free(lookedup);
 }
 
-void test_worktree_open__open_discovered_submodule_worktree(void)
+void test_worktree_open__open_from_nonworktree_fails(void)
 {
-	worktree_fixture parent_fixture =
-		WORKTREE_FIXTURE_INIT("submodules", WORKTREE_PARENT);
-	worktree_fixture child_fixture =
-		WORKTREE_FIXTURE_INIT(NULL, WORKTREE_CHILD);
-	git_buf path = GIT_BUF_INIT;
-	git_repository *repo;
-
-	setup_fixture_worktree(&parent_fixture);
-	cl_git_pass(p_rename(
-		"submodules/testrepo/.gitted",
-		"submodules/testrepo/.git"));
-	setup_fixture_worktree(&child_fixture);
-
-	cl_git_pass(git_repository_discover(&path,
-		git_repository_workdir(child_fixture.worktree), false, NULL));
-	cl_git_pass(git_repository_open(&repo, path.ptr));
-	cl_assert_equal_s(git_repository_workdir(child_fixture.worktree),
-		git_repository_workdir(repo));
+	git_worktree *wt;
 
-	git_buf_free(&path);
-	git_repository_free(repo);
-	cleanup_fixture_worktree(&child_fixture);
-	cleanup_fixture_worktree(&parent_fixture);
+	cl_git_fail(git_worktree_open_from_repository(&wt, fixture.repo));
 }
diff --git a/tests/worktree/refs.c b/tests/worktree/refs.c
index ccac8be..b9a0560 100644
--- a/tests/worktree/refs.c
+++ b/tests/worktree/refs.c
@@ -1,4 +1,6 @@
 #include "clar_libgit2.h"
+#include "path.h"
+#include "refs.h"
 #include "worktree.h"
 #include "worktree_helpers.h"
 
@@ -128,3 +130,27 @@ void test_worktree_refs__delete_succeeds_after_pruning_worktree(void)
        cl_git_pass(git_branch_delete(branch));
        git_reference_free(branch);
 }
+
+void test_worktree_refs__creating_refs_uses_commondir(void)
+{
+	   git_reference *head, *branch, *lookup;
+	   git_commit *commit;
+	   git_buf refpath = GIT_BUF_INIT;
+
+	   cl_git_pass(git_buf_joinpath(&refpath,
+		       git_repository_commondir(fixture.worktree), "refs/heads/testbranch"));
+	   cl_assert(!git_path_exists(refpath.ptr));
+
+	   cl_git_pass(git_repository_head(&head, fixture.worktree));
+	   cl_git_pass(git_commit_lookup(&commit, fixture.worktree, git_reference_target(head)));
+	   cl_git_pass(git_branch_create(&branch, fixture.worktree, "testbranch", commit, 0));
+	   cl_git_pass(git_branch_lookup(&lookup, fixture.worktree, "testbranch", GIT_BRANCH_LOCAL));
+	   cl_assert(git_reference_cmp(branch, lookup) == 0);
+	   cl_assert(git_path_exists(refpath.ptr));
+
+	   git_reference_free(lookup);
+	   git_reference_free(branch);
+	   git_reference_free(head);
+	   git_commit_free(commit);
+	   git_buf_free(&refpath);
+}
diff --git a/tests/worktree/submodule.c b/tests/worktree/submodule.c
new file mode 100644
index 0000000..5620775
--- /dev/null
+++ b/tests/worktree/submodule.c
@@ -0,0 +1,92 @@
+#include "clar_libgit2.h"
+#include "repository.h"
+#include "worktree.h"
+#include "worktree_helpers.h"
+
+#define WORKTREE_PARENT "submodules-worktree-parent"
+#define WORKTREE_CHILD "submodules-worktree-child"
+
+static worktree_fixture parent
+    = WORKTREE_FIXTURE_INIT("submodules", WORKTREE_PARENT);
+static worktree_fixture child
+    = WORKTREE_FIXTURE_INIT(NULL, WORKTREE_CHILD);
+
+void test_worktree_submodule__initialize(void)
+{
+	setup_fixture_worktree(&parent);
+
+	cl_git_pass(p_rename(
+		"submodules/testrepo/.gitted",
+		"submodules/testrepo/.git"));
+
+	setup_fixture_worktree(&child);
+}
+
+void test_worktree_submodule__cleanup(void)
+{
+	cleanup_fixture_worktree(&child);
+	cleanup_fixture_worktree(&parent);
+}
+
+void test_worktree_submodule__submodule_worktree_parent(void)
+{
+	cl_assert(git_repository_path(parent.worktree) != NULL);
+	cl_assert(git_repository_workdir(parent.worktree) != NULL);
+
+	cl_assert(!parent.repo->is_worktree);
+	cl_assert(parent.worktree->is_worktree);
+}
+
+void test_worktree_submodule__submodule_worktree_child(void)
+{
+	cl_assert(!parent.repo->is_worktree);
+	cl_assert(parent.worktree->is_worktree);
+	cl_assert(child.worktree->is_worktree);
+}
+
+void test_worktree_submodule__open_discovered_submodule_worktree(void)
+{
+	git_buf path = GIT_BUF_INIT;
+	git_repository *repo;
+
+	cl_git_pass(git_repository_discover(&path,
+		git_repository_workdir(child.worktree), false, NULL));
+	cl_git_pass(git_repository_open(&repo, path.ptr));
+	cl_assert_equal_s(git_repository_workdir(child.worktree),
+		git_repository_workdir(repo));
+
+	git_buf_free(&path);
+	git_repository_free(repo);
+}
+
+void test_worktree_submodule__resolve_relative_url(void)
+{
+	git_buf wt_path = GIT_BUF_INIT;
+	git_buf sm_relative_path = GIT_BUF_INIT, wt_relative_path = GIT_BUF_INIT;
+	git_repository *repo;
+	git_worktree *wt;
+
+	cl_git_pass(git_futils_mkdir("subdir", 0755, GIT_MKDIR_PATH));
+	cl_git_pass(git_path_prettify_dir(&wt_path, "subdir", NULL));
+	cl_git_pass(git_buf_joinpath(&wt_path, wt_path.ptr, "wt"));
+
+	/* Open child repository, which is a submodule */
+	cl_git_pass(git_repository_open(&child.repo, WORKTREE_CHILD));
+
+	/* Create worktree of submodule repository */
+	cl_git_pass(git_worktree_add(&wt, child.repo, "subdir", wt_path.ptr));
+	cl_git_pass(git_repository_open_from_worktree(&repo, wt));
+
+	cl_git_pass(git_submodule_resolve_url(&sm_relative_path, repo,
+		    "../" WORKTREE_CHILD));
+	cl_git_pass(git_submodule_resolve_url(&wt_relative_path, child.repo,
+		    "../" WORKTREE_CHILD));
+
+	cl_assert_equal_s(sm_relative_path.ptr, wt_relative_path.ptr);
+
+	git_worktree_free(wt);
+	git_repository_free(repo);
+	git_buf_free(&wt_path);
+	git_buf_free(&sm_relative_path);
+	git_buf_free(&wt_relative_path);
+}
diff --git a/tests/worktree/worktree.c b/tests/worktree/worktree.c
index f0c4235..6e90e6a 100644
--- a/tests/worktree/worktree.c
+++ b/tests/worktree/worktree.c
@@ -115,11 +115,12 @@ void test_worktree_worktree__lookup(void)
 
 	cl_git_pass(git_worktree_lookup(&wt, fixture.repo, "testrepo-worktree"));
 
-	git_buf_printf(&gitdir_path, "%s/worktrees/%s", fixture.repo->commondir, "testrepo-worktree");
+	cl_git_pass(git_buf_joinpath(&gitdir_path, fixture.repo->commondir, "worktrees/testrepo-worktree/"));
 
 	cl_assert_equal_s(wt->gitdir_path, gitdir_path.ptr);
-	cl_assert_equal_s(wt->parent_path, fixture.repo->gitdir);
+	cl_assert_equal_s(wt->parent_path, fixture.repo->workdir);
 	cl_assert_equal_s(wt->gitlink_path, fixture.worktree->gitlink);
+	cl_assert_equal_s(wt->commondir_path, fixture.repo->gitdir);
 	cl_assert_equal_s(wt->commondir_path, fixture.repo->commondir);
 
 	git_buf_free(&gitdir_path);
@@ -305,7 +306,9 @@ void test_worktree_worktree__init_submodule(void)
 	cl_git_pass(git_worktree_add(&worktree, sm, "repo-worktree", path.ptr));
 	cl_git_pass(git_repository_open_from_worktree(&wt, worktree));
 
+	cl_git_pass(git_path_prettify_dir(&path, path.ptr, NULL));
 	cl_assert_equal_s(path.ptr, wt->workdir);
+	cl_git_pass(git_path_prettify_dir(&path, sm->commondir, NULL));
 	cl_assert_equal_s(sm->commondir, wt->commondir);
 
 	cl_git_pass(git_buf_joinpath(&path, sm->gitdir, "worktrees/repo-worktree/"));