filter::file tests: test filter_list_apply_to_file

Test that filter_list_apply_to_file works and can accept repo-relative
paths.

tests/filter/file.c

+#include "clar_libgit2.h"
+#include "git2/sys/filter.h"
+#include "crlf.h"
+#include "buffer.h"
+
+static git_repository *g_repo = NULL;
+
+void test_filter_file__initialize(void)
+{
+	git_reference *head_ref;
+	git_commit *head;
+
+	g_repo = cl_git_sandbox_init("crlf");
+
+	cl_git_mkfile("crlf/.gitattributes",
+		"*.txt text\n*.bin binary\n*.crlf text eol=crlf\n*.lf text eol=lf\n");
+
+	cl_repo_set_bool(g_repo, "core.autocrlf", true);
+
+	cl_git_pass(git_repository_head(&head_ref, g_repo));
+	cl_git_pass(git_reference_peel((git_object **)&head, head_ref, GIT_OBJ_COMMIT));
+	cl_git_pass(git_reset(g_repo, (git_object *)head, GIT_RESET_HARD, NULL));
+
+	git_commit_free(head);
+	git_reference_free(head_ref);
+}
+
+void test_filter_file__cleanup(void)
+{
+	cl_git_sandbox_cleanup();
+}
+
+void test_filter_file__apply(void)
+{
+	git_filter_list *fl;
+	git_filter *crlf;
+	git_buf buf = GIT_BUF_INIT;
+
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
+
+	crlf = git_filter_lookup(GIT_FILTER_CRLF);
+	cl_assert(crlf != NULL);
+
+	cl_git_pass(git_filter_list_push(fl, crlf, NULL));
+
+	cl_git_pass(git_filter_list_apply_to_file(&buf, fl, g_repo, "all-crlf"));
+	cl_assert_equal_s("crlf\ncrlf\ncrlf\ncrlf\n", buf.ptr);
+
+	git_buf_free(&buf);
+	git_filter_list_free(fl);
+}
+
+struct buf_writestream {
+	git_writestream base;
+	git_buf buf;
+};
+
+int buf_writestream_write(git_writestream *s, const char *buf, size_t len)
+{
+	struct buf_writestream *stream = (struct buf_writestream *)s;
+	return git_buf_put(&stream->buf, buf, len);
+}
+
+int buf_writestream_close(git_writestream *s)
+{
+	return 0;
+}
+
+void buf_writestream_free(git_writestream *s)
+{
+	struct buf_writestream *stream = (struct buf_writestream *)s;
+	git_buf_free(&stream->buf);
+}
+
+void test_filter_file__apply_stream(void)
+{
+	git_filter_list *fl;
+	git_filter *crlf;
+	struct buf_writestream write_target = { {
+		buf_writestream_write,
+		buf_writestream_close,
+		buf_writestream_free } };
+
+	cl_git_pass(git_filter_list_new(
+		&fl, g_repo, GIT_FILTER_TO_ODB, 0));
+
+	crlf = git_filter_lookup(GIT_FILTER_CRLF);
+	cl_assert(crlf != NULL);
+
+	cl_git_pass(git_filter_list_push(fl, crlf, NULL));
+
+	cl_git_pass(git_filter_list_stream_file(fl, g_repo, "all-crlf", (git_writestream *)&write_target));
+	cl_assert_equal_s("crlf\ncrlf\ncrlf\ncrlf\n", write_target.buf.ptr);
+
+	git_filter_list_free(fl);
+}