tests: verify parsing logic for smart packets

The commits following this commit are about to introduce quite a lot of
refactoring and tightening of the smart packet parser. Unfortunately, we
do not yet have any tests despite our online tests that verify that our
parser does not regress upon changes. This is doubly unfortunate as our
online tests aren't executed by default.

Add new tests that exercise the smart parsing logic directly by
executing `git_pkt_parse_line`.

tests/transports/smart/packet.c

+#include "clar_libgit2.h"
+#include "transports/smart.h"
+
+enum expected_status {
+	PARSE_SUCCESS,
+	PARSE_FAILURE
+};
+
+static void assert_flush_parses(const char *line)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_FLUSH);
+	cl_assert_equal_strn(endptr, line + 4, linelen - 4);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_data_pkt_parses(const char *line, const char *expected_data, size_t expected_len)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_data *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_DATA);
+	cl_assert_equal_i(pkt->len, expected_len);
+	cl_assert_equal_strn(pkt->data, expected_data, expected_len);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_sideband_progress_parses(const char *line, const char *expected_data, size_t expected_len)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_progress *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_PROGRESS);
+	cl_assert_equal_i(pkt->len, expected_len);
+	cl_assert_equal_strn(pkt->data, expected_data, expected_len);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_error_parses(const char *line, const char *expected_error, size_t expected_len)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_err *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_ERR);
+	cl_assert_equal_i(pkt->len, expected_len);
+	cl_assert_equal_strn(pkt->error, expected_error, expected_len);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_ack_parses(const char *line, const char *expected_oid, enum git_ack_status expected_status)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_ack *pkt;
+	git_oid oid;
+
+	cl_git_pass(git_oid_fromstr(&oid, expected_oid));
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_ACK);
+	cl_assert_equal_oid(&pkt->oid, &oid);
+	cl_assert_equal_i(pkt->status, expected_status);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_nak_parses(const char *line)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_NAK);
+	cl_assert_equal_strn(endptr, line + 7, linelen - 7);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_comment_parses(const char *line, const char *expected_comment)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_comment *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_COMMENT);
+	cl_assert_equal_strn(pkt->comment, expected_comment, strlen(expected_comment));
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_ok_parses(const char *line, const char *expected_ref)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_ok *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_OK);
+	cl_assert_equal_strn(pkt->ref, expected_ref, strlen(expected_ref));
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_unpack_parses(const char *line, bool ok)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_unpack *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_UNPACK);
+	cl_assert_equal_i(pkt->unpack_ok, ok);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_ng_parses(const char *line, const char *expected_ref, const char *expected_msg)
+{
+	size_t linelen = strlen(line) + 1;
+	const char *endptr;
+	git_pkt_ng *pkt;
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_NG);
+	cl_assert_equal_strn(pkt->ref, expected_ref, strlen(expected_ref));
+	cl_assert_equal_strn(pkt->msg, expected_msg, strlen(expected_msg));
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+#define assert_ref_parses(line, expected_oid, expected_ref, expected_capabilities) \
+	assert_ref_parses_(line, sizeof(line), expected_oid, expected_ref, expected_capabilities)
+
+static void assert_ref_parses_(const char *line, size_t linelen, const char *expected_oid,
+	const char *expected_ref, const char *expected_capabilities)
+{
+	const char *endptr;
+	git_pkt_ref *pkt;
+	git_oid oid;
+
+	cl_git_pass(git_oid_fromstr(&oid, expected_oid));
+
+	cl_git_pass(git_pkt_parse_line((git_pkt **) &pkt, line, &endptr, linelen));
+	cl_assert_equal_i(pkt->type, GIT_PKT_REF);
+	cl_assert_equal_oid(&pkt->head.oid, &oid);
+	cl_assert_equal_strn(pkt->head.name, expected_ref, strlen(expected_ref));
+	if (expected_capabilities)
+		cl_assert_equal_strn(pkt->capabilities, expected_capabilities, strlen(expected_capabilities));
+	else
+		cl_assert_equal_p(NULL, pkt->capabilities);
+
+	git_pkt_free((git_pkt *) pkt);
+}
+
+static void assert_pkt_fails(const char *line)
+{
+	const char *endptr;
+	git_pkt *pkt;
+	cl_git_fail(git_pkt_parse_line(&pkt, line, &endptr, strlen(line) + 1));
+}
+
+void test_transports_smart_packet__parsing_garbage_fails(void)
+{
+	assert_pkt_fails("0foobar");
+	assert_pkt_fails("00foobar");
+	assert_pkt_fails("000foobar");
+	assert_pkt_fails("0001");
+	assert_pkt_fails("");
+	assert_pkt_fails("0");
+	assert_pkt_fails("0i00");
+	assert_pkt_fails("f");
+}
+
+void test_transports_smart_packet__flush_parses(void)
+{
+	assert_flush_parses("0000");
+	assert_flush_parses("0000foobar");
+}
+
+void test_transports_smart_packet__data_pkt(void)
+{
+	assert_pkt_fails("000foobar");
+	assert_pkt_fails("0001o");
+	assert_pkt_fails("0001\1");
+	assert_data_pkt_parses("0005\1", "", 0);
+	assert_pkt_fails("0009\1o");
+	assert_data_pkt_parses("0009\1data", "data", 4);
+	assert_data_pkt_parses("000a\1data", "data", 5);
+}
+
+void test_transports_smart_packet__sideband_progress_pkt(void)
+{
+	assert_pkt_fails("0001\2");
+	assert_sideband_progress_parses("0005\2", "", 0);
+	assert_pkt_fails("0009\2o");
+	assert_sideband_progress_parses("0009\2data", "data", 4);
+	assert_sideband_progress_parses("000a\2data", "data", 5);
+}
+
+void test_transports_smart_packet__sideband_err_pkt(void)
+{
+	assert_pkt_fails("0001\3");
+	assert_error_parses("0005\3", "", 0);
+	assert_pkt_fails("0009\3o");
+	assert_error_parses("0009\3data", "data", 4);
+	assert_error_parses("000a\3data", "data", 5);
+}
+
+void test_transports_smart_packet__ack_pkt(void)
+{
+	assert_ack_parses("0030ACK 0000000000000000000000000000000000000000",
+			  "0000000000000000000000000000000000000000", 0);
+	assert_ack_parses("0039ACK 0000000000000000000000000000000000000000 continue",
+			  "0000000000000000000000000000000000000000",
+			  GIT_ACK_CONTINUE);
+	assert_ack_parses("0037ACK 0000000000000000000000000000000000000000 common",
+			  "0000000000000000000000000000000000000000",
+			  GIT_ACK_COMMON);
+	assert_ack_parses("0037ACK 0000000000000000000000000000000000000000 ready",
+			  "0000000000000000000000000000000000000000",
+			  GIT_ACK_READY);
+
+	/* TODO: these should fail as they don't have OIDs */
+	assert_ack_parses("0007ACK", "0000000000000000000000000000000000000000", 0);
+	assert_ack_parses("0008ACK ", "0000000000000000000000000000000000000000", 0);
+
+	/* TODO: this one is missing a space and should thus fail */
+	assert_ack_parses("0036ACK00000000000000000x0000000000000000000000 ready",
+			  "0000000000000000000000000000000000000000", 0);
+
+	/* TODO: the following ones have invalid OIDs and should thus fail */
+	assert_ack_parses("0037ACK 00000000000000000x0000000000000000000000 ready",
+			  "0000000000000000000000000000000000000000", GIT_ACK_READY);
+	assert_ack_parses("0036ACK 000000000000000000000000000000000000000 ready",
+			  "0000000000000000000000000000000000000000", 0);
+	assert_ack_parses("0036ACK 00000000000000000x0000000000000000000000ready",
+			  "0000000000000000000000000000000000000000", 0);
+
+	/* TODO: this one has an invalid status and should thus fail */
+	assert_ack_parses("0036ACK 0000000000000000000000000000000000000000 read",
+			  "0000000000000000000000000000000000000000", 0);
+}
+
+void test_transports_smart_packet__nak_pkt(void)
+{
+	assert_nak_parses("0007NAK");
+	assert_pkt_fails("0007NaK");
+	assert_pkt_fails("0007nak");
+	assert_nak_parses("0007NAKfoobar");
+	assert_pkt_fails("0007nakfoobar");
+	assert_pkt_fails("0007 NAK");
+}
+
+void test_transports_smart_packet__error_pkt(void)
+{
+	assert_pkt_fails("0007ERR");
+	assert_pkt_fails("0008ERRx");
+	assert_error_parses("0008ERR ", "", 0);
+	assert_error_parses("000EERR ERRMSG", "ERRMSG", 6);
+}
+
+void test_transports_smart_packet__comment_pkt(void)
+{
+	assert_comment_parses("0005#", "");
+	assert_comment_parses("000B#foobar", "#fooba");
+	assert_comment_parses("000C#foobar", "#foobar");
+	assert_comment_parses("001A#this is a comment\nfoo", "#this is a comment\nfoo");
+}
+
+void test_transports_smart_packet__ok_pkt(void)
+{
+	/*
+	 * TODO: the trailing slash is currently mandatory. Check
+	 * if we should really enforce this. As this test is part
+	 * of a security release, I feel uneasy to change
+	 * behaviour right now and leave it for a later point.
+	 */
+	assert_pkt_fails("0007ok\n");
+	assert_ok_parses("0008ok \n", "");
+	assert_ok_parses("0009ok x\n", "x");
+	assert_pkt_fails("0013OK ref/foo/bar\n");
+	assert_ok_parses("0013ok ref/foo/bar\n", "ref/foo/bar");
+	assert_ok_parses("0012ok ref/foo/bar\n", "ref/foo/bar");
+}
+
+void test_transports_smart_packet__ng_pkt(void)
+{
+	/* TODO: same as for ok pkt */
+	assert_pkt_fails("0007ng\n");
+	assert_pkt_fails("0008ng \n");
+	assert_pkt_fails("000Bng ref\n");
+	assert_pkt_fails("000Bng ref\n");
+	/* TODO: is this a valid packet line? Probably not. */
+	assert_ng_parses("000Ang  x\n", "", "x");
+	assert_ng_parses("000Fng ref msg\n", "ref", "msg");
+	assert_ng_parses("000Fng ref msg\n", "ref", "msg");
+}
+
+void test_transports_smart_packet__unpack_pkt(void)
+{
+	assert_unpack_parses("000Dunpack ok", 1);
+	assert_unpack_parses("000Dunpack ng error-msg", 0);
+	/* TODO: the following tests should fail */
+	assert_unpack_parses("000Aunpack", 0);
+	assert_unpack_parses("0011unpack foobar", 0);
+	assert_unpack_parses("0010unpack ng ok", 0);
+	assert_unpack_parses("0010unpack okfoo", 1);
+}
+
+void test_transports_smart_packet__ref_pkt(void)
+{
+	assert_pkt_fails("002C0000000000000000000000000000000000000000");
+	assert_pkt_fails("002D0000000000000000000000000000000000000000\n");
+	assert_pkt_fails("00300000000000000000000000000000000000000000HEAD");
+	assert_pkt_fails("004800000000x0000000000000000000000000000000 refs/heads/master\0multi_ack");
+	assert_ref_parses(
+		"003F0000000000000000000000000000000000000000 refs/heads/master\0",
+		"0000000000000000000000000000000000000000", "refs/heads/master", "");
+	assert_ref_parses(
+		"00480000000000000000000000000000000000000000 refs/heads/master\0multi_ack",
+		"0000000000000000000000000000000000000000", "refs/heads/master", "multi_ack");
+	assert_ref_parses(
+		"00460000000000000000000000000000000000000000 refs/heads/master\0one two",
+		"0000000000000000000000000000000000000000", "refs/heads/master", "one two");
+	assert_ref_parses(
+		"00310000000000000000000000000000000000000000 HEAD",
+		"0000000000000000000000000000000000000000", "HEAD", NULL);
+	assert_pkt_fails("0031000000000000000000000000000000000000000 HEAD");
+	assert_ref_parses(
+		"00360000000000000000000000000000000000000000 HEAD HEAD",
+		"0000000000000000000000000000000000000000", "HEAD HEAD", NULL);
+}