thodg/libgit2

diff --git a/tests/odb/backend/backend_helpers.c b/tests/odb/backend/backend_helpers.c
index 139d2fc..5427992 100644
--- a/tests/odb/backend/backend_helpers.c
+++ b/tests/odb/backend/backend_helpers.c
@@ -123,6 +123,18 @@ static int fake_backend__read_prefix(
 	return 0;
 }
 
+static int fake_backend__refresh(git_odb_backend *backend)
+{
+	fake_backend *fake;
+
+	fake = (fake_backend *)backend;
+
+	fake->refresh_calls++;
+
+	return 0;
+}
+
+
 static void fake_backend__free(git_odb_backend *_backend)
 {
 	fake_backend *backend;
@@ -134,7 +146,8 @@ static void fake_backend__free(git_odb_backend *_backend)
 
 int build_fake_backend(
 	git_odb_backend **out,
-	const fake_object *objects)
+	const fake_object *objects,
+	bool support_refresh)
 {
 	fake_backend *backend;
 
@@ -143,12 +156,12 @@ int build_fake_backend(
 
 	backend->parent.version = GIT_ODB_BACKEND_VERSION;
 
-	backend->parent.refresh = NULL;
 	backend->objects = objects;
 
 	backend->parent.read = fake_backend__read;
 	backend->parent.read_prefix = fake_backend__read_prefix;
 	backend->parent.read_header = fake_backend__read_header;
+	backend->parent.refresh = support_refresh ? fake_backend__refresh : NULL;
 	backend->parent.exists = fake_backend__exists;
 	backend->parent.exists_prefix = fake_backend__exists_prefix;
 	backend->parent.free = &fake_backend__free;
diff --git a/tests/odb/backend/backend_helpers.h b/tests/odb/backend/backend_helpers.h
index 5c393c0..32d7a8b 100644
--- a/tests/odb/backend/backend_helpers.h
+++ b/tests/odb/backend/backend_helpers.h
@@ -13,10 +13,12 @@ typedef struct {
 	int read_calls;
 	int read_header_calls;
 	int read_prefix_calls;
+	int refresh_calls;
 
 	const fake_object *objects;
 } fake_backend;
 
 int build_fake_backend(
 	git_odb_backend **out,
-	const fake_object *objects);
+	const fake_object *objects,
+	bool support_refresh);
diff --git a/tests/odb/backend/multiple.c b/tests/odb/backend/multiple.c
index 1c6068d..5f1eacd 100644
--- a/tests/odb/backend/multiple.c
+++ b/tests/odb/backend/multiple.c
@@ -29,10 +29,10 @@ void test_odb_backend_multiple__initialize(void)
 	_obj = NULL;
 	_repo = cl_git_sandbox_init("testrepo.git");
 
-	cl_git_pass(build_fake_backend(&backend, _objects_filled));
+	cl_git_pass(build_fake_backend(&backend, _objects_filled, false));
 	_fake_filled = (fake_backend *)backend;
 
-	cl_git_pass(build_fake_backend(&backend, _objects_empty));
+	cl_git_pass(build_fake_backend(&backend, _objects_empty, false));
 	_fake_empty = (fake_backend *)backend;
 }
 
diff --git a/tests/odb/backend/nonrefreshing.c b/tests/odb/backend/nonrefreshing.c
index ede48ad..2db10ef 100644
--- a/tests/odb/backend/nonrefreshing.c
+++ b/tests/odb/backend/nonrefreshing.c
@@ -23,7 +23,7 @@ static void setup_repository_and_backend(void)
 
 	_repo = cl_git_sandbox_init("testrepo.git");
 
-	cl_git_pass(build_fake_backend(&backend, _objects));
+	cl_git_pass(build_fake_backend(&backend, _objects, false));
 
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
 	cl_git_pass(git_odb_add_backend(odb, backend, 10));
diff --git a/tests/odb/backend/refreshing.c b/tests/odb/backend/refreshing.c
new file mode 100644
index 0000000..9e49298
--- /dev/null
+++ b/tests/odb/backend/refreshing.c
@@ -0,0 +1,176 @@
+#include "clar_libgit2.h"
+#include "repository.h"
+#include "backend_helpers.h"
+
+static git_repository *_repo;
+static fake_backend *_fake;
+
+#define NONEXISTING_HASH "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"
+#define EXISTING_HASH "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
+
+static const fake_object _objects[] = {
+	{ EXISTING_HASH, "" },
+	{ NULL, NULL }
+};
+
+static git_oid _nonexisting_oid;
+static git_oid _existing_oid;
+
+static void setup_repository_and_backend(void)
+{
+	git_odb *odb = NULL;
+	git_odb_backend *backend = NULL;
+
+	_repo = cl_git_sandbox_init("testrepo.git");
+
+	cl_git_pass(build_fake_backend(&backend, _objects, true));
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_git_pass(git_odb_add_backend(odb, backend, 10));
+
+	_fake = (fake_backend *)backend;
+}
+
+void test_odb_backend_refreshing__initialize(void)
+{
+	git_oid_fromstr(&_nonexisting_oid, NONEXISTING_HASH);
+	git_oid_fromstr(&_existing_oid, EXISTING_HASH);
+	setup_repository_and_backend();
+}
+
+void test_odb_backend_refreshing__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_odb_backend_refreshing__exists_is_invoked_twice_on_failure(void)
+{
+	git_odb *odb;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_b(false, git_odb_exists(odb, &_nonexisting_oid));
+
+	cl_assert_equal_i(2, _fake->exists_calls);
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__read_is_invoked_twice_on_failure(void)
+{
+	git_object *obj;
+
+	cl_git_fail_with(
+		git_object_lookup(&obj, _repo, &_nonexisting_oid, GIT_OBJECT_ANY),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(2, _fake->read_calls);
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__readprefix_is_invoked_twice_on_failure(void)
+{
+	git_object *obj;
+
+	cl_git_fail_with(
+		git_object_lookup_prefix(&obj, _repo, &_nonexisting_oid, 7, GIT_OBJECT_ANY),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(2, _fake->read_prefix_calls);
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__readheader_is_invoked_twice_on_failure(void)
+{
+	git_odb *odb;
+	size_t len;
+	git_object_t type;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+
+	cl_git_fail_with(
+		git_odb_read_header(&len, &type, odb, &_nonexisting_oid),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(2, _fake->read_header_calls);
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__exists_is_invoked_once_on_success(void)
+{
+	git_odb *odb;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_b(true, git_odb_exists(odb, &_existing_oid));
+
+	cl_assert_equal_i(1, _fake->exists_calls);
+	cl_assert_equal_i(0, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__read_is_invoked_once_on_success(void)
+{
+	git_object *obj;
+
+	cl_git_pass(git_object_lookup(&obj, _repo, &_existing_oid, GIT_OBJECT_ANY));
+
+	cl_assert_equal_i(1, _fake->read_calls);
+	cl_assert_equal_i(0, _fake->refresh_calls);
+
+	git_object_free(obj);
+}
+
+void test_odb_backend_refreshing__readprefix_is_invoked_once_on_success(void)
+{
+	git_object *obj;
+
+	cl_git_pass(git_object_lookup_prefix(&obj, _repo, &_existing_oid, 7, GIT_OBJECT_ANY));
+
+	cl_assert_equal_i(1, _fake->read_prefix_calls);
+	cl_assert_equal_i(0, _fake->refresh_calls);
+
+	git_object_free(obj);
+}
+
+void test_odb_backend_refreshing__readheader_is_invoked_once_on_success(void)
+{
+	git_odb *odb;
+	size_t len;
+	git_object_t type;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+
+	cl_git_pass(git_odb_read_header(&len, &type, odb, &_existing_oid));
+
+	cl_assert_equal_i(1, _fake->read_header_calls);
+	cl_assert_equal_i(0, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__read_is_invoked_twice_when_revparsing_a_full_oid(void)
+{
+	git_object *obj;
+
+	cl_git_fail_with(
+		git_revparse_single(&obj, _repo, "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"),
+		GIT_ENOTFOUND);
+
+	cl_assert_equal_i(2, _fake->read_calls);
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__refresh_is_invoked(void)
+{
+	git_odb *odb;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_i(0, git_odb_refresh(odb));
+
+	cl_assert_equal_i(1, _fake->refresh_calls);
+}
+
+void test_odb_backend_refreshing__refresh_suppressed_with_no_refresh(void)
+{
+	git_odb *odb;
+
+	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
+	cl_assert_equal_b(false, git_odb_exists_ext(odb, &_nonexisting_oid, GIT_ODB_LOOKUP_NO_REFRESH));
+
+	cl_assert_equal_i(0, _fake->refresh_calls);
+}
diff --git a/tests/odb/backend/simple.c b/tests/odb/backend/simple.c
index 484dcba..6c9293a 100644
--- a/tests/odb/backend/simple.c
+++ b/tests/odb/backend/simple.c
@@ -13,7 +13,7 @@ static void setup_backend(const fake_object *objs)
 {
 	git_odb_backend *backend;
 
-	cl_git_pass(build_fake_backend(&backend, objs));
+	cl_git_pass(build_fake_backend(&backend, objs, false));
 
 	cl_git_pass(git_repository_odb__weakptr(&_odb, _repo));
 	cl_git_pass(git_odb_add_backend(_odb, backend, 10));