1 files changed, 133 insertions, 0 deletions
diff --git a/tests/libgit2/diff/externalmodifications.c b/tests/libgit2/diff/externalmodifications.c
new file mode 100644
index 000000000..df62c3316
--- /dev/null
+++ b/tests/libgit2/diff/externalmodifications.c
@@ -0,0 +1,133 @@
+#include "clar_libgit2.h"
+#include "../checkout/checkout_helpers.h"
+
+#include "index.h"
+#include "repository.h"
+
+static git_repository *g_repo;
+
+void test_diff_externalmodifications__initialize(void)
+{
+	g_repo = cl_git_sandbox_init("testrepo2");
+}
+
+void test_diff_externalmodifications__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+	g_repo = NULL;
+}
+
+void test_diff_externalmodifications__file_becomes_smaller(void)
+{
+	git_index *index;
+	git_diff *diff;
+	git_patch* patch;
+	git_str path = GIT_STR_INIT;
+	char big_string[500001];
+
+	cl_git_pass(git_str_joinpath(&path, git_repository_workdir(g_repo), "README"));
+
+	/* Modify the file with a large string */
+	memset(big_string, '\n', sizeof(big_string) - 1);
+	big_string[sizeof(big_string) - 1] = '\0';
+	cl_git_mkfile(path.ptr, big_string);
+
+	/* Get a diff */
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
+	cl_assert_equal_i(1, git_diff_num_deltas(diff));
+	cl_assert_equal_i(500000, git_diff_get_delta(diff, 0)->new_file.size);
+
+	/* Simulate file modification after we've gotten the diff.
+	 * Write a shorter string to ensure that we don't mmap 500KB from
+	 * the previous revision, which would most likely crash. */
+	cl_git_mkfile(path.ptr, "hello");
+
+	/* Attempt to get a patch */
+	cl_git_fail(git_patch_from_diff(&patch, diff, 0));
+
+	git_index_free(index);
+	git_diff_free(diff);
+	git_str_dispose(&path);
+}
+
+void test_diff_externalmodifications__file_becomes_empty(void)
+{
+	git_index *index;
+	git_diff *diff;
+	git_patch* patch;
+	git_str path = GIT_STR_INIT;
+
+	cl_git_pass(git_str_joinpath(&path, git_repository_workdir(g_repo), "README"));
+
+	/* Modify the file */
+	cl_git_mkfile(path.ptr, "hello");
+
+	/* Get a diff */
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
+	cl_assert_equal_i(1, git_diff_num_deltas(diff));
+	cl_assert_equal_i(5, git_diff_get_delta(diff, 0)->new_file.size);
+
+	/* Empty out the file after we've gotten the diff */
+	cl_git_mkfile(path.ptr, "");
+
+	/* Attempt to get a patch */
+	cl_git_fail(git_patch_from_diff(&patch, diff, 0));
+
+	git_index_free(index);
+	git_diff_free(diff);
+	git_str_dispose(&path);
+}
+
+void test_diff_externalmodifications__file_deleted(void)
+{
+	git_index *index;
+	git_diff *diff;
+	git_patch* patch;
+	git_str path = GIT_STR_INIT;
+
+	cl_git_pass(git_str_joinpath(&path, git_repository_workdir(g_repo), "README"));
+
+	/* Get a diff */
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
+	cl_assert_equal_i(0, git_diff_num_deltas(diff));
+
+	/* Delete the file */
+	cl_git_rmfile(path.ptr);
+
+	/* Attempt to get a patch */
+	cl_git_fail(git_patch_from_diff(&patch, diff, 0));
+
+	git_index_free(index);
+	git_diff_free(diff);
+	git_str_dispose(&path);
+}
+
+void test_diff_externalmodifications__empty_file_becomes_non_empty(void)
+{
+	git_index *index;
+	git_diff *diff;
+	git_patch* patch;
+	git_str path = GIT_STR_INIT;
+
+	cl_git_pass(git_str_joinpath(&path, git_repository_workdir(g_repo), "README"));
+
+	/* Empty out the file */
+	cl_git_mkfile(path.ptr, "");
+
+	/* Get a diff */
+	cl_git_pass(git_repository_index(&index, g_repo));
+	cl_git_pass(git_diff_index_to_workdir(&diff, g_repo, index, NULL));
+	cl_assert_equal_i(1, git_diff_num_deltas(diff));
+	cl_assert_equal_i(0, git_diff_get_delta(diff, 0)->new_file.size);
+
+	/* Simulate file modification after we've gotten the diff */
+	cl_git_mkfile(path.ptr, "hello");
+	cl_git_fail(git_patch_from_diff(&patch, diff, 0));
+
+	git_index_free(index);
+	git_diff_free(diff);
+	git_str_dispose(&path);
+}