tests: odb: move fake backend into its own file

The fake backend used by the test suite `odb::backend::nonrefreshing` is
useful to have some low-level tests for the ODB layer. As such, we move
the implementation into its own `backend_helpers` module.

tests/odb/backend/backend_helpers.c

+#include "clar_libgit2.h"
+#include "git2/sys/odb_backend.h"
+#include "backend_helpers.h"
+
+static int fake_backend__exists(git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->exists_calls++;
+
+	return (fake->error_code == GIT_OK);
+}
+
+static int fake_backend__read(
+	void **buffer_p, size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(buffer_p);
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_calls++;
+
+	*len_p = 0;
+	*buffer_p = NULL;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static int fake_backend__read_header(
+	size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *oid)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(oid);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_header_calls++;
+
+	*len_p = 0;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static int fake_backend__read_prefix(
+	git_oid *out_oid, void **buffer_p, size_t *len_p, git_otype *type_p,
+	git_odb_backend *backend, const git_oid *short_oid, size_t len)
+{
+	fake_backend *fake;
+
+	GIT_UNUSED(buffer_p);
+	GIT_UNUSED(len_p);
+	GIT_UNUSED(type_p);
+	GIT_UNUSED(short_oid);
+	GIT_UNUSED(len);
+
+	fake = (fake_backend *)backend;
+
+	fake->read_prefix_calls++;
+
+	git_oid_cpy(out_oid, &fake->oid);
+	*len_p = 0;
+	*buffer_p = NULL;
+	*type_p = GIT_OBJ_BLOB;
+
+	return fake->error_code;
+}
+
+static void fake_backend__free(git_odb_backend *_backend)
+{
+	fake_backend *backend;
+
+	backend = (fake_backend *)_backend;
+
+	git__free(backend);
+}
+
+int build_fake_backend(
+	git_odb_backend **out,
+	git_error_code error_code,
+	const git_oid *oid)
+{
+	fake_backend *backend;
+
+	backend = git__calloc(1, sizeof(fake_backend));
+	GITERR_CHECK_ALLOC(backend);
+
+	backend->parent.version = GIT_ODB_BACKEND_VERSION;
+
+	backend->parent.refresh = NULL;
+	backend->error_code = error_code;
+
+	backend->parent.read = fake_backend__read;
+	backend->parent.read_prefix = fake_backend__read_prefix;
+	backend->parent.read_header = fake_backend__read_header;
+	backend->parent.exists = fake_backend__exists;
+	backend->parent.free = &fake_backend__free;
+
+	git_oid_cpy(&backend->oid, oid);
+
+	*out = (git_odb_backend *)backend;
+
+	return 0;
+}

tests/odb/backend/backend_helpers.h

+#include "git2/sys/odb_backend.h"
+
+typedef struct {
+	git_odb_backend parent;
+
+	git_error_code error_code;
+	git_oid oid;
+
+	int exists_calls;
+	int read_calls;
+	int read_header_calls;
+	int read_prefix_calls;
+} fake_backend;
+
+int build_fake_backend(
+	git_odb_backend **out,
+	git_error_code error_code,
+	const git_oid *oid);

tests/odb/backend/nonrefreshing.c

 #include "clar_libgit2.h"
-#include "git2/sys/odb_backend.h"
 #include "repository.h"
-
-typedef struct fake_backend {
-	git_odb_backend parent;
-
-	git_error_code error_code;
-
-	int exists_calls;
-	int read_calls;
-	int read_header_calls;
-	int read_prefix_calls;
-} fake_backend;
+#include "backend_helpers.h"
 
 static git_repository *_repo;
 static fake_backend *_fake;
-static git_oid _oid;
 
 #define HASH "deadbeefdeadbeefdeadbeefdeadbeefdeadbeef"
 #define EMPTY_HASH "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391"
 
-static int fake_backend__exists(git_odb_backend *backend, const git_oid *oid)
-{
-	fake_backend *fake;
-
-	GIT_UNUSED(oid);
-
-	fake = (fake_backend *)backend;
-
-	fake->exists_calls++;
-
-	return (fake->error_code == GIT_OK);
-}
-
-static int fake_backend__read(
-	void **buffer_p, size_t *len_p, git_otype *type_p,
-	git_odb_backend *backend, const git_oid *oid)
-{
-	fake_backend *fake;
-
-	GIT_UNUSED(buffer_p);
-	GIT_UNUSED(len_p);
-	GIT_UNUSED(type_p);
-	GIT_UNUSED(oid);
-
-	fake = (fake_backend *)backend;
-
-	fake->read_calls++;
-
-	*len_p = 0;
-	*buffer_p = NULL;
-	*type_p = GIT_OBJ_BLOB;
-
-	return fake->error_code;
-}
-
-static int fake_backend__read_header(
-	size_t *len_p, git_otype *type_p,
-	git_odb_backend *backend, const git_oid *oid)
-{
-	fake_backend *fake;
-
-	GIT_UNUSED(len_p);
-	GIT_UNUSED(type_p);
-	GIT_UNUSED(oid);
-
-	fake = (fake_backend *)backend;
-
-	fake->read_header_calls++;
-
-	*len_p = 0;
-	*type_p = GIT_OBJ_BLOB;
-
-	return fake->error_code;
-}
-
-static int fake_backend__read_prefix(
-	git_oid *out_oid, void **buffer_p, size_t *len_p, git_otype *type_p,
-	git_odb_backend *backend, const git_oid *short_oid,	size_t len)
-{
-	fake_backend *fake;
-
-	GIT_UNUSED(buffer_p);
-	GIT_UNUSED(len_p);
-	GIT_UNUSED(type_p);
-	GIT_UNUSED(short_oid);
-	GIT_UNUSED(len);
-
-	fake = (fake_backend *)backend;
-
-	fake->read_prefix_calls++;
-
-	git_oid_cpy(out_oid, &_oid);
-	*len_p = 0;
-	*buffer_p = NULL;
-	*type_p = GIT_OBJ_BLOB;
-
-	return fake->error_code;
-}
-
-static void fake_backend__free(git_odb_backend *_backend)
-{
-	fake_backend *backend;
-
-	backend = (fake_backend *)_backend;
-
-	git__free(backend);
-}
-
-static int build_fake_backend(
-	git_odb_backend **out,
-	git_error_code error_code)
-{
-	fake_backend *backend;
-
-	backend = git__calloc(1, sizeof(fake_backend));
-	GITERR_CHECK_ALLOC(backend);
-
-	backend->parent.version = GIT_ODB_BACKEND_VERSION;
-
-	backend->parent.refresh = NULL;
-	backend->error_code = error_code;
-
-	backend->parent.read = fake_backend__read;
-	backend->parent.read_prefix = fake_backend__read_prefix;
-	backend->parent.read_header = fake_backend__read_header;
-	backend->parent.exists = fake_backend__exists;
-	backend->parent.free = &fake_backend__free;
-
-	*out = (git_odb_backend *)backend;
-
-	return 0;
-}
-
 static void setup_repository_and_backend(git_error_code error_code, const char *hash)
 {
 	git_odb *odb = NULL;
 	git_odb_backend *backend = NULL;
+	git_oid oid;
 
 	_repo = cl_git_sandbox_init("testrepo.git");
 
-	cl_git_pass(build_fake_backend(&backend, error_code));
+	cl_git_pass(git_oid_fromstr(&oid, hash));
+	cl_git_pass(build_fake_backend(&backend, error_code, &oid));
 
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
 	cl_git_pass(git_odb_add_backend(odb, backend, 10));
 
 	_fake = (fake_backend *)backend;
-
-	cl_git_pass(git_oid_fromstr(&_oid, hash));
 }
 
 void test_odb_backend_nonrefreshing__cleanup(void)
@@ -162,7 +37,7 @@ void test_odb_backend_nonrefreshing__exists_is_invoked_once_on_failure(void)
 	setup_repository_and_backend(GIT_ENOTFOUND, HASH);
 
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
-	cl_assert_equal_b(false, git_odb_exists(odb, &_oid));
+	cl_assert_equal_b(false, git_odb_exists(odb, &_fake->oid));
 
 	cl_assert_equal_i(1, _fake->exists_calls);
 }
@@ -174,7 +49,7 @@ void test_odb_backend_nonrefreshing__read_is_invoked_once_on_failure(void)
 	setup_repository_and_backend(GIT_ENOTFOUND, HASH);
 
 	cl_git_fail_with(
-		git_object_lookup(&obj, _repo, &_oid, GIT_OBJ_ANY),
+		git_object_lookup(&obj, _repo, &_fake->oid, GIT_OBJ_ANY),
 		GIT_ENOTFOUND);
 
 	cl_assert_equal_i(1, _fake->read_calls);
@@ -187,7 +62,7 @@ void test_odb_backend_nonrefreshing__readprefix_is_invoked_once_on_failure(void)
 	setup_repository_and_backend(GIT_ENOTFOUND, HASH);
 
 	cl_git_fail_with(
-		git_object_lookup_prefix(&obj, _repo, &_oid, 7, GIT_OBJ_ANY),
+		git_object_lookup_prefix(&obj, _repo, &_fake->oid, 7, GIT_OBJ_ANY),
 		GIT_ENOTFOUND);
 
 	cl_assert_equal_i(1, _fake->read_prefix_calls);
@@ -204,7 +79,7 @@ void test_odb_backend_nonrefreshing__readheader_is_invoked_once_on_failure(void)
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
 
 	cl_git_fail_with(
-		git_odb_read_header(&len, &type, odb, &_oid),
+		git_odb_read_header(&len, &type, odb, &_fake->oid),
 		GIT_ENOTFOUND);
 
 	cl_assert_equal_i(1, _fake->read_header_calls);
@@ -217,7 +92,7 @@ void test_odb_backend_nonrefreshing__exists_is_invoked_once_on_success(void)
 	setup_repository_and_backend(GIT_OK, HASH);
 
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
-	cl_assert_equal_b(true, git_odb_exists(odb, &_oid));
+	cl_assert_equal_b(true, git_odb_exists(odb, &_fake->oid));
 
 	cl_assert_equal_i(1, _fake->exists_calls);
 }
@@ -228,7 +103,7 @@ void test_odb_backend_nonrefreshing__read_is_invoked_once_on_success(void)
 
 	setup_repository_and_backend(GIT_OK, EMPTY_HASH);
 
-	cl_git_pass(git_object_lookup(&obj, _repo, &_oid, GIT_OBJ_ANY));
+	cl_git_pass(git_object_lookup(&obj, _repo, &_fake->oid, GIT_OBJ_ANY));
 
 	cl_assert_equal_i(1, _fake->read_calls);
 
@@ -241,7 +116,7 @@ void test_odb_backend_nonrefreshing__readprefix_is_invoked_once_on_success(void)
 
 	setup_repository_and_backend(GIT_OK, EMPTY_HASH);
 
-	cl_git_pass(git_object_lookup_prefix(&obj, _repo, &_oid, 7, GIT_OBJ_ANY));
+	cl_git_pass(git_object_lookup_prefix(&obj, _repo, &_fake->oid, 7, GIT_OBJ_ANY));
 
 	cl_assert_equal_i(1, _fake->read_prefix_calls);
 
@@ -258,7 +133,7 @@ void test_odb_backend_nonrefreshing__readheader_is_invoked_once_on_success(void)
 
 	cl_git_pass(git_repository_odb__weakptr(&odb, _repo));
 
-	cl_git_pass(git_odb_read_header(&len, &type, odb, &_oid));
+	cl_git_pass(git_odb_read_header(&len, &type, odb, &_fake->oid));
 
 	cl_assert_equal_i(1, _fake->read_header_calls);
 }