Add unit tests for index manipulation

Three new unit tests, t06XX files have been added.

	t0601-read: tests for loading index files from disk,
				for creating in-memory indexes and for accessing
				index entries.
	t0602-write: tests for writing index files back to disk
	t0603-sort: tests for properly sorting the entries array of an index

Two test indexes have been added in 'tests/resources/':

	test/resources/index: a sample index from a libgit2 repository

	test/resources/gitgit.index: a sample index from a git.git
		repository (includes TREE extension data)

Signed-off-by: Vicent Marti <tanoku@gmail.com>

tests/t0601-read.c

+#include "test_lib.h"
+#include "test_helpers.h"
+#include "index.h"
+
+#include <git/odb.h>
+#include <git/index.h>
+
+#define TEST_INDEX_PATH "../resources/index"
+#define TEST_INDEX2_PATH "../resources/gitgit.index"
+
+#define TEST_INDEX_ENTRY_COUNT 109
+#define TEST_INDEX2_ENTRY_COUNT 1437
+
+struct test_entry {
+	unsigned int index;
+	char path[128];
+	size_t file_size;
+	uint32_t mtime;
+};
+
+struct test_entry TEST_ENTRIES[] = {
+	{4, "Makefile", 5064, 0x4C3F7F33},
+	{62, "tests/Makefile", 2631, 0x4C3F7F33},
+	{36, "src/index.c", 10014, 0x4C43368D},
+	{6, "git.git-authors", 2709, 0x4C3F7F33},
+	{48, "src/revobject.h", 1448, 0x4C3F7FE2}
+};
+
+BEGIN_TEST(index_loadempty_test)
+	git_index *index;
+
+	index = git_index_alloc("in-memory-index");
+	must_be_true(index != NULL);
+	must_be_true(index->on_disk == 0);
+
+	must_pass(git_index_read(index));
+
+	must_be_true(index->on_disk == 0);
+	must_be_true(index->entry_count == 0);
+	must_be_true(index->sorted);
+
+	git_index_free(index);
+END_TEST
+
+BEGIN_TEST(index_load_test)
+	git_index *index;
+	unsigned int i;
+
+	index = git_index_alloc(TEST_INDEX_PATH);
+	must_be_true(index != NULL);
+	must_be_true(index->on_disk);
+
+	must_pass(git_index_read(index));
+
+	must_be_true(index->on_disk);
+	must_be_true(index->entry_count == TEST_INDEX_ENTRY_COUNT);
+	must_be_true(index->sorted);
+
+	for (i = 0; i < ARRAY_SIZE(TEST_ENTRIES); ++i) {
+		git_index_entry *e = &index->entries[TEST_ENTRIES[i].index];
+
+		must_be_true(strcmp(e->path, TEST_ENTRIES[i].path) == 0);
+		must_be_true(e->mtime.seconds == TEST_ENTRIES[i].mtime);
+		must_be_true(e->file_size == TEST_ENTRIES[i].file_size);
+	}
+
+	git_index_free(index);
+END_TEST
+
+BEGIN_TEST(index2_load_test)
+	git_index *index;
+
+	index = git_index_alloc(TEST_INDEX2_PATH);
+	must_be_true(index != NULL);
+	must_be_true(index->on_disk);
+
+	must_pass(git_index_read(index));
+
+	must_be_true(index->on_disk);
+	must_be_true(index->entry_count == TEST_INDEX2_ENTRY_COUNT);
+	must_be_true(index->sorted);
+	must_be_true(index->tree != NULL);
+
+	git_index_free(index);
+END_TEST
+
+BEGIN_TEST(index_find_test)
+	git_index *index;
+	unsigned int i;
+
+	index = git_index_alloc(TEST_INDEX_PATH);
+	must_be_true(index != NULL);
+	must_pass(git_index_read(index));
+
+	for (i = 0; i < ARRAY_SIZE(TEST_ENTRIES); ++i) {
+		int idx = git_index_find(index, TEST_ENTRIES[i].path);
+		must_be_true((unsigned int)idx == TEST_ENTRIES[i].index);
+	}
+
+	git_index_free(index);
+END_TEST
+
+BEGIN_TEST(index_findempty_test)
+	git_index *index;
+	unsigned int i;
+
+	index = git_index_alloc("fake-index");
+	must_be_true(index != NULL);
+
+	for (i = 0; i < ARRAY_SIZE(TEST_ENTRIES); ++i) {
+		int idx = git_index_find(index, TEST_ENTRIES[i].path);
+		must_be_true(idx == GIT_ENOTFOUND);
+	}
+
+	git_index_free(index);
+END_TEST

tests/t0602-write.c

+#include "test_lib.h"
+#include "test_helpers.h"
+#include "index.h"
+
+#include <git/odb.h>
+#include <git/index.h>
+
+#define TEST_INDEX_PATH "../resources/index"
+
+int filecmp(const char *filename1, const char *filename2)
+{
+	git_file file1, file2;
+	struct stat stat1, stat2;
+
+	/* char buffer1[1024], buffer2[1024]; */
+
+	file1 = gitfo_open(filename1, O_RDONLY);
+	file2 = gitfo_open(filename2, O_RDONLY);
+
+	if (file1 < 0 || file2 < 0)
+		return GIT_ERROR;
+
+	gitfo_fstat(file1, &stat1);
+	gitfo_fstat(file2, &stat2);
+
+	if (stat1.st_size != stat2.st_size)
+		return GIT_ERROR;
+
+	/* TODO: byte-per-byte comparison */
+
+	return 0;
+}
+
+BEGIN_TEST(index_load_test)
+	git_index *index;
+	git_filelock out_file;
+
+	index = git_index_alloc(TEST_INDEX_PATH);
+	must_be_true(index != NULL);
+	must_pass(git_index_read(index));
+	must_be_true(index->on_disk);
+
+	must_pass(git_filelock_init(&out_file, "index_rewrite"));
+	must_pass(git_filelock_lock(&out_file, 0));
+	must_pass(git_index__write(index, &out_file));
+	must_pass(git_filelock_commit(&out_file));
+
+	git_index_free(index);
+END_TEST

tests/t0603-sort.c

+#include "test_lib.h"
+#include "test_helpers.h"
+#include "index.h"
+
+#include <git/odb.h>
+#include <git/index.h>
+
+#define TEST_INDEX_PATH "../t0600-objects/index"
+
+void print_entries(git_index *index)
+{
+	unsigned int i;
+
+	for (i = 0; i < index->entry_count; ++i)
+		printf("%d: %s\n", i, index->entries[i].path);
+}
+
+void randomize_entries(git_index *index)
+{
+	unsigned int i, j;
+	git_index_entry tmp;
+
+	srand(time(NULL));
+
+	for (i = 0; i < index->entry_count; ++i) {
+		j = rand() % index->entry_count;
+		memcpy(&tmp, &index->entries[j], sizeof(git_index_entry));
+		memcpy(&index->entries[j], &index->entries[i], sizeof(git_index_entry));
+		memcpy(&index->entries[i], &tmp, sizeof(git_index_entry));
+	}
+
+	index->sorted = 0;
+}
+
+BEGIN_TEST(index_sort_test)
+	git_index *index;
+	unsigned int i;
+
+	index = git_index_alloc(TEST_INDEX_PATH);
+	must_be_true(index != NULL);
+	must_pass(git_index_read(index));
+
+	randomize_entries(index);
+
+	git_index__sort(index);
+	must_be_true(index->sorted);
+
+	for (i = 1; i < index->entry_count; ++i)
+		must_be_true(strcmp(index->entries[i - 1].path,
+					index->entries[i].path) < 0);
+
+	git_index_free(index);
+END_TEST
+
+BEGIN_TEST(index_sort_empty_test)
+	git_index *index;
+	index = git_index_alloc("fake-index");
+	must_be_true(index != NULL);
+
+	git_index__sort(index);
+	must_be_true(index->sorted);
+
+	git_index_free(index);
+END_TEST