worktree: implement functions reading HEAD

Implement `git_repository_head_for_worktree` and
`git_repository_head_detached_for_worktree` for directly accessing a
worktree's HEAD without opening it as a `git_repository` first.

2 files changed, 64 insertions, 0 deletions

diff --git a/tests/worktree/repository.c b/tests/worktree/repository.c
new file mode 100644
index 000000000..5c7595c64
--- /dev/null
+++ b/tests/worktree/repository.c
@@ -0,0 +1,63 @@
+#include "clar_libgit2.h"
+#include "worktree_helpers.h"
+#include "submodule/submodule_helpers.h"
+
+#include "repository.h"
+
+#define COMMON_REPO "testrepo"
+#define WORKTREE_REPO "testrepo-worktree"
+
+static worktree_fixture fixture =
+	WORKTREE_FIXTURE_INIT(COMMON_REPO, WORKTREE_REPO);
+
+void test_worktree_repository__initialize(void)
+{
+	setup_fixture_worktree(&fixture);
+}
+
+void test_worktree_repository__cleanup(void)
+{
+	cleanup_fixture_worktree(&fixture);
+}
+
+void test_worktree_repository__head(void)
+{
+	git_reference *ref, *head;
+
+	cl_git_pass(git_reference_lookup(&ref, fixture.repo, "refs/heads/testrepo-worktree"));
+	cl_git_pass(git_repository_head_for_worktree(&head, fixture.repo, "testrepo-worktree"));
+	cl_assert(git_reference_cmp(ref, head) == 0);
+
+	git_reference_free(ref);
+	git_reference_free(head);
+}
+
+void test_worktree_repository__head_fails_for_invalid_worktree(void)
+{
+	git_reference *head = NULL;
+
+	cl_git_fail(git_repository_head_for_worktree(&head, fixture.repo, "invalid"));
+	cl_assert(head == NULL);
+}
+
+void test_worktree_repository__head_detached(void)
+{
+	git_reference *ref, *head;
+
+	cl_git_pass(git_reference_lookup(&ref, fixture.repo, "refs/heads/testrepo-worktree"));
+	cl_git_pass(git_repository_set_head_detached(fixture.worktree, &ref->target.oid));
+
+	cl_assert(git_repository_head_detached(fixture.worktree));
+	cl_assert(git_repository_head_detached_for_worktree(fixture.repo, "testrepo-worktree"));
+	cl_git_fail(git_repository_head_for_worktree(&head, fixture.repo, "testrepo-worktree"));
+
+	git_reference_free(ref);
+}
+
+void test_worktree_repository__head_detached_fails_for_invalid_worktree(void)
+{
+	git_reference *head = NULL;
+
+	cl_git_fail(git_repository_head_detached_for_worktree(fixture.repo, "invalid"));
+	cl_assert(head == NULL);
+}
diff --git a/tests/worktree/worktree.c b/tests/worktree/worktree.c
index 7758b1b1c..756cf387b 100644
--- a/tests/worktree/worktree.c
+++ b/tests/worktree/worktree.c
@@ -1,6 +1,7 @@
 #include "clar_libgit2.h"
 #include "worktree_helpers.h"
 
+#include "checkout.h"
 #include "repository.h"
 #include "worktree.h"