Teach `git_patch_from_diff` about parsed diffsethomson/patch_from_diff

Ensure that `git_patch_from_diff` can return the patch for parsed diffs,
not just generate a patch for a generated diff.

1 files changed, 45 insertions, 0 deletions

diff --git a/tests/diff/parse.c b/tests/diff/parse.c
index 83000a92d..a06813d1b 100644
--- a/tests/diff/parse.c
+++ b/tests/diff/parse.c
@@ -2,6 +2,7 @@
 #include "patch.h"
 #include "patch_parse.h"
 #include "diff_helpers.h"
+#include "../src/diff.h"
 
 #include "../patch/patch_common.h"
 
@@ -151,3 +152,47 @@ void test_diff_parse__can_parse_generated_diff(void)
 		GIT_DIFF_FIND_COPIES_FROM_UNMODIFIED | GIT_DIFF_FIND_EXACT_MATCH_ONLY);
 }
 
+void test_diff_parse__get_patch_from_diff(void)
+{
+	git_repository *repo;
+	git_diff *computed, *parsed;
+	git_tree *a, *b;
+	git_diff_options opts = GIT_DIFF_OPTIONS_INIT;
+	git_buf computed_buf = GIT_BUF_INIT;
+	git_patch *patch_computed, *patch_parsed;
+
+	repo = cl_git_sandbox_init("diff");
+
+	opts.flags = GIT_DIFF_SHOW_BINARY;
+
+	cl_assert((a = resolve_commit_oid_to_tree(repo,
+		"d70d245ed97ed2aa596dd1af6536e4bfdb047b69")) != NULL);
+	cl_assert((b = resolve_commit_oid_to_tree(repo,
+		"7a9e0b02e63179929fed24f0a3e0f19168114d10")) != NULL);
+
+	cl_git_pass(git_diff_tree_to_tree(&computed, repo, a, b, &opts));
+	cl_git_pass(git_diff_to_buf(&computed_buf,
+		computed, GIT_DIFF_FORMAT_PATCH));
+	cl_git_pass(git_patch_from_diff(&patch_computed, computed, 0));
+
+	cl_git_pass(git_diff_from_buffer(&parsed,
+		computed_buf.ptr, computed_buf.size));
+	cl_git_pass(git_patch_from_diff(&patch_parsed, parsed, 0));
+
+	cl_assert_equal_i(
+		git_patch_num_hunks(patch_computed),
+		git_patch_num_hunks(patch_parsed));
+
+	git_patch_free(patch_computed);
+	git_patch_free(patch_parsed);
+
+	git_tree_free(a);
+	git_tree_free(b);
+
+	git_diff_free(computed);
+	git_diff_free(parsed);
+
+	git_buf_free(&computed_buf);
+
+	cl_git_sandbox_cleanup();
+}