Use git_diff_get_stats in example/diff + refactor

This takes the `--stat` and related example options in the example
diff.c program and converts them to use the `git_diff_get_stats`
API which nicely formats stats for you.

I went to add bar-graph scaling to the stats formatter and noticed
that the `git_diff_stats` structure was holding on to all of the
`git_patch` objects.  Unfortunately, each of these objects keeps
the full text of the diff in memory, so this is very expensive.  I
ended up modifying `git_diff_stats` to keep just the data that it
needs to keep and allowed it to release the patches.  Then, I added
width scaling to the output on top of that.

In making the diff example program match 'git diff' output, I ended
up removing an newline from the sumamry output which I then had to
compensate for in the email formatting to match the expectations.

Lastly, I went through and refactored the tests to use a couple of
helper functions and reduce the overall amount of code there.

1 files changed, 107 insertions, 250 deletions

diff --git a/tests/diff/stats.c b/tests/diff/stats.c
index 131b7681d..055019f69 100644
--- a/tests/diff/stats.c
+++ b/tests/diff/stats.c
@@ -5,246 +5,173 @@
 #include "commit.h"
 #include "diff.h"
 
-static git_repository *repo;
+static git_repository *_repo;
+static git_diff_stats *_stats;
 
 void test_diff_stats__initialize(void)
 {
-	repo = cl_git_sandbox_init("diff_format_email");
+	_repo = cl_git_sandbox_init("diff_format_email");
 }
 
 void test_diff_stats__cleanup(void)
 {
+	git_diff_stats_free(_stats); _stats = NULL;
 	cl_git_sandbox_cleanup();
 }
 
-void test_diff_stats__stat(void)
+static void diff_stats_from_commit_oid(
+	git_diff_stats **stats, const char *oidstr, bool rename)
 {
 	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
-	git_buf buf = GIT_BUF_INIT;
+	git_commit *commit;
+	git_diff *diff;
+
+	git_oid_fromstr(&oid, oidstr);
+	cl_git_pass(git_commit_lookup(&commit, _repo, &oid));
+	cl_git_pass(git_diff__commit(&diff, _repo, commit, NULL));
+	if (rename)
+		cl_git_pass(git_diff_find_similar(diff, NULL));
+	cl_git_pass(git_diff_get_stats(stats, diff));
+
+	git_diff_free(diff);
+	git_commit_free(commit);
+}
 
+void test_diff_stats__stat(void)
+{
+	git_buf buf = GIT_BUF_INIT;
 	const char *stat =
 	" file1.txt | 8 +++++---\n" \
 	" 1 file changed, 5 insertions(+), 3 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "9264b96c6d104d0e07ae33d3007b6a48246c6f92");
+	diff_stats_from_commit_oid(
+		&_stats, "9264b96c6d104d0e07ae33d3007b6a48246c6f92", false);
 
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
+	cl_assert_equal_sz(1, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(5, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(3, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 1);
-	cl_assert(git_diff_stats_insertions(stats) == 5);
-	cl_assert(git_diff_stats_deletions(stats) == 3);
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
 	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__multiple_hunks(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt | 5 +++--\n" \
 	" file3.txt | 6 ++++--\n" \
 	" 2 files changed, 7 insertions(+), 4 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "cd471f0d8770371e1bc78bcbb38db4c7e4106bd2");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
+	diff_stats_from_commit_oid(
+		&_stats, "cd471f0d8770371e1bc78bcbb38db4c7e4106bd2", false);
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 2);
-	cl_assert(git_diff_stats_insertions(stats) == 7);
-	cl_assert(git_diff_stats_deletions(stats) == 4);
+	cl_assert_equal_sz(2, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(7, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(4, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__numstat(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	"3       2       file2.txt\n"
 	"4       2       file3.txt\n";
 
-	git_oid_fromstr(&oid, "cd471f0d8770371e1bc78bcbb38db4c7e4106bd2");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_NUMBER));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
+	diff_stats_from_commit_oid(
+		&_stats, "cd471f0d8770371e1bc78bcbb38db4c7e4106bd2", false);
 
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_NUMBER, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__shortstat(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" 1 file changed, 5 insertions(+), 3 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "9264b96c6d104d0e07ae33d3007b6a48246c6f92");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
+	diff_stats_from_commit_oid(
+		&_stats, "9264b96c6d104d0e07ae33d3007b6a48246c6f92", false);
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 1);
-	cl_assert(git_diff_stats_insertions(stats) == 5);
-	cl_assert(git_diff_stats_deletions(stats) == 3);
+	cl_assert_equal_sz(1, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(5, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(3, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_SHORT));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_SHORT, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt => file2.txt.renamed | 1 +\n"
 	" file3.txt => file3.txt.renamed | 4 +++-\n"
-	" 2 files changed, 4 insertions(+), 1 deletions(-)\n";
-
-	git_oid_fromstr(&oid, "8947a46e2097638ca6040ad4877246f4186ec3bd");
+	" 2 files changed, 4 insertions(+), 1 deletion(-)\n";
 
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-	cl_git_pass(git_diff_find_similar(diff, NULL));
+	diff_stats_from_commit_oid(
+		&_stats, "8947a46e2097638ca6040ad4877246f4186ec3bd", true);
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 2);
-	cl_assert(git_diff_stats_insertions(stats) == 4);
-	cl_assert(git_diff_stats_deletions(stats) == 1);
+	cl_assert_equal_sz(2, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(4, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(1, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename_nochanges(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt.renamed => file2.txt.renamed2 | 0\n"
 	" file3.txt.renamed => file3.txt.renamed2 | 0\n"
 	" 2 files changed, 0 insertions(+), 0 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "3991dce9e71a0641ca49a6a4eea6c9e7ff402ed4");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-	cl_git_pass(git_diff_find_similar(diff, NULL));
+	diff_stats_from_commit_oid(
+		&_stats, "3991dce9e71a0641ca49a6a4eea6c9e7ff402ed4", true);
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 2);
-	cl_assert(git_diff_stats_insertions(stats) == 0);
-	cl_assert(git_diff_stats_deletions(stats) == 0);
+	cl_assert_equal_sz(2, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(0, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(0, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename_and_modifiy(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt.renamed2                      | 2 +-\n"
 	" file3.txt.renamed2 => file3.txt.renamed | 0\n"
-	" 2 files changed, 1 insertions(+), 1 deletions(-)\n";
+	" 2 files changed, 1 insertion(+), 1 deletion(-)\n";
 
-	git_oid_fromstr(&oid, "4ca10087e696d2ba78d07b146a118e9a7096ed4f");
+	diff_stats_from_commit_oid(
+		&_stats, "4ca10087e696d2ba78d07b146a118e9a7096ed4f", true);
 
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-	cl_git_pass(git_diff_find_similar(diff, NULL));
+	cl_assert_equal_sz(2, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(1, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(1, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 2);
-	cl_assert(git_diff_stats_insertions(stats) == 1);
-	cl_assert(git_diff_stats_deletions(stats) == 1);
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename_no_find(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt         | 5 -----\n"
 	" file2.txt.renamed | 6 ++++++\n"
@@ -252,33 +179,21 @@ void test_diff_stats__rename_no_find(void)
 	" file3.txt.renamed | 7 +++++++\n"
 	" 4 files changed, 13 insertions(+), 10 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "8947a46e2097638ca6040ad4877246f4186ec3bd");
+	diff_stats_from_commit_oid(
+		&_stats, "8947a46e2097638ca6040ad4877246f4186ec3bd", false);
 
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
+	cl_assert_equal_sz(4, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(13, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(10, git_diff_stats_deletions(_stats));
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 4);
-	cl_assert(git_diff_stats_insertions(stats) == 13);
-	cl_assert(git_diff_stats_deletions(stats) == 10);
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename_nochanges_no_find(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt.renamed  | 6 ------\n"
 	" file2.txt.renamed2 | 6 ++++++\n"
@@ -286,143 +201,85 @@ void test_diff_stats__rename_nochanges_no_find(void)
 	" file3.txt.renamed2 | 7 +++++++\n"
 	" 4 files changed, 13 insertions(+), 13 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "3991dce9e71a0641ca49a6a4eea6c9e7ff402ed4");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
+	diff_stats_from_commit_oid(
+		&_stats, "3991dce9e71a0641ca49a6a4eea6c9e7ff402ed4", false);
 
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 4);
-	cl_assert(git_diff_stats_insertions(stats) == 13);
-	cl_assert(git_diff_stats_deletions(stats) == 13);
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
+	cl_assert_equal_sz(4, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(13, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(13, git_diff_stats_deletions(_stats));
 
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__rename_and_modifiy_no_find(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file2.txt.renamed2 | 2 +-\n"
 	" file3.txt.renamed  | 7 +++++++\n"
 	" file3.txt.renamed2 | 7 -------\n"
 	" 3 files changed, 8 insertions(+), 8 deletions(-)\n";
 
-	git_oid_fromstr(&oid, "4ca10087e696d2ba78d07b146a118e9a7096ed4f");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 3);
-	cl_assert(git_diff_stats_insertions(stats) == 8);
-	cl_assert(git_diff_stats_deletions(stats) == 8);
+	diff_stats_from_commit_oid(
+		&_stats, "4ca10087e696d2ba78d07b146a118e9a7096ed4f", false);
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
+	cl_assert_equal_sz(3, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(8, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(8, git_diff_stats_deletions(_stats));
 
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__binary(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
-	/* TODO: Actually 0 bytes here should be 5!. Seems like we don't load the new content for binary files? */
 	const char *stat =
 	" binary.bin | Bin 3 -> 0 bytes\n"
 	" 1 file changed, 0 insertions(+), 0 deletions(-)\n";
+	/* TODO: Actually 0 bytes here should be 5!. Seems like we don't load the new content for binary files? */
 
-	git_oid_fromstr(&oid, "8d7523f6fcb2404257889abe0d96f093d9f524f9");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-	cl_assert(git_diff_stats_files_changed(stats) == 1);
-	cl_assert(git_diff_stats_insertions(stats) == 0);
-	cl_assert(git_diff_stats_deletions(stats) == 0);
+	diff_stats_from_commit_oid(
+		&_stats, "8d7523f6fcb2404257889abe0d96f093d9f524f9", false);
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
+	cl_assert_equal_sz(1, git_diff_stats_files_changed(_stats));
+	cl_assert_equal_sz(0, git_diff_stats_insertions(_stats));
+	cl_assert_equal_sz(0, git_diff_stats_deletions(_stats));
 
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__binary_numstat(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	"-       -       binary.bin\n";
 
-	git_oid_fromstr(&oid, "8d7523f6fcb2404257889abe0d96f093d9f524f9");
-
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-
-	cl_git_pass(git_diff_get_stats(&stats, diff));
+	diff_stats_from_commit_oid(
+		&_stats, "8d7523f6fcb2404257889abe0d96f093d9f524f9", false);
 
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_NUMBER));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_NUMBER, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }
 
 void test_diff_stats__mode_change(void)
 {
-	git_oid oid;
-	git_commit *commit = NULL;
-	git_diff *diff = NULL;
-	git_diff_stats *stats = NULL;
 	git_buf buf = GIT_BUF_INIT;
-
 	const char *stat =
 	" file1.txt.renamed | 0\n" \
 	" 1 file changed, 0 insertions(+), 0 deletions(-)\n" \
-	" mode change 100644 => 100755 file1.txt.renamed\n" \
-	"\n";
+		" mode change 100644 => 100755 file1.txt.renamed\n";
 
-	git_oid_fromstr(&oid, "7ade76dd34bba4733cf9878079f9fd4a456a9189");
+	diff_stats_from_commit_oid(
+		&_stats, "7ade76dd34bba4733cf9878079f9fd4a456a9189", false);
 
-	cl_git_pass(git_commit_lookup(&commit, repo, &oid));
-	cl_git_pass(git_diff__commit(&diff, repo, commit, NULL));
-
-	cl_git_pass(git_diff_get_stats(&stats, diff));
-
-	cl_git_pass(git_diff_stats_to_buf(&buf, stats, GIT_DIFF_STATS_FULL | GIT_DIFF_STATS_INCLUDE_SUMMARY));
-	cl_assert(strcmp(git_buf_cstr(&buf), stat) == 0);
-
-	git_diff_stats_free(stats);
-	git_diff_free(diff);
-	git_commit_free(commit);
+	cl_git_pass(git_diff_stats_to_buf(&buf, _stats, GIT_DIFF_STATS_FULL | GIT_DIFF_STATS_INCLUDE_SUMMARY, 0));
+	cl_assert_equal_s(stat, git_buf_cstr(&buf));
 	git_buf_free(&buf);
 }