wire: add bigsize parsing tests.

Based on:
	https://github.com/lightningnetwork/lightning-rfc/pull/640

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

wire/test/run-bigsize.c

@@ -0,0 +1,282 @@
+#include <ccan/array_size/array_size.h>
+#include <ccan/str/hex/hex.h>
+#include <ccan/tal/grab_file/grab_file.h>
+#include <ccan/tal/str/str.h>
+#include <common/json.c>
+#include <common/utils.h>
+
+static const char *reason;
+#define SUPERVERBOSE(r) do { if (!reason) reason = (r); } while(0)
+
+#include <wire/fromwire.c>
+#include <wire/towire.c>
+
+/* AUTOGENERATED MOCKS START */
+/* AUTOGENERATED MOCKS END */
+
+/* BOLT-EXPERIMENTAL #1:
+ *
+ * A correct implementation should pass against these test vectors:
+ * ```json
+ * [
+ *     {
+ *         "name": "zero",
+ *         "value": 0,
+ *         "bytes": "00"
+ *     },
+ *     {
+ *         "name": "one byte high",
+ *         "value": 252,
+ *         "bytes": "fc"
+ *     },
+ *     {
+ *         "name": "two byte low",
+ *         "value": 253,
+ *         "bytes": "fd00fd"
+ *     },
+ *     {
+ *         "name": "two byte high",
+ *         "value": 65535,
+ *         "bytes": "fdffff"
+ *     },
+ *     {
+ *         "name": "four byte low",
+ *         "value": 65536,
+ *         "bytes": "fe00010000"
+ *     },
+ *     {
+ *         "name": "four byte high",
+ *         "value": 4294967295,
+ *         "bytes": "feffffffff"
+ *     },
+ *     {
+ *         "name": "eight byte low",
+ *         "value": 4294967296,
+ *         "bytes": "ff0000000100000000"
+ *     },
+ *     {
+ *         "name": "eight byte high",
+ *         "value": 18446744073709551615,
+ *         "bytes": "ffffffffffffffffff"
+ *     },
+ *     {
+ *         "name": "two byte not canonical",
+ *         "value": 0,
+ *         "bytes": "fd00fc",
+ *         "exp_error": "decoded varint is not canonical"
+ *     },
+ *     {
+ *         "name": "four byte not canonical",
+ *         "value": 0,
+ *         "bytes": "fe0000ffff",
+ *         "exp_error": "decoded varint is not canonical"
+ *     },
+ *     {
+ *         "name": "eight byte not canonical",
+ *         "value": 0,
+ *         "bytes": "ff00000000ffffffff",
+ *         "exp_error": "decoded varint is not canonical"
+ *     },
+ *     {
+ *         "name": "two byte short read",
+ *         "value": 0,
+ *         "bytes": "fd00",
+ *         "exp_error": "unexpected EOF"
+ *     },
+ *     {
+ *         "name": "four byte short read",
+ *         "value": 0,
+ *         "bytes": "feffff",
+ *         "exp_error": "unexpected EOF"
+ *     },
+ *     {
+ *         "name": "eight byte short read",
+ *         "value": 0,
+ *         "bytes": "ffffffffff",
+ *         "exp_error": "unexpected EOF"
+ *     },
+ *     {
+ *         "name": "one byte no read",
+ *         "value": 0,
+ *         "bytes": "",
+ *         "exp_error": "EOF"
+ *     },
+ *     {
+ *         "name": "two byte no read",
+ *         "value": 0,
+ *         "bytes": "fd",
+ *         "exp_error": "unexpected EOF"
+ *     },
+ *     {
+ *         "name": "four byte no read",
+ *         "value": 0,
+ *         "bytes": "fe",
+ *         "exp_error": "unexpected EOF"
+ *     },
+ *     {
+ *         "name": "eight byte no read",
+ *         "value": 0,
+ *         "bytes": "ff",
+ *         "exp_error": "unexpected EOF"
+ *     }
+ * ]
+ * ```
+ */
+static void test_decode(const char *json, const jsmntok_t toks[])
+{
+	size_t i;
+	const jsmntok_t *t;
+
+	json_for_each_arr(i, t, toks) {
+		const jsmntok_t *err = json_get_member(json, t, "exp_error");
+		const jsmntok_t *bytes = json_get_member(json, t, "bytes");
+		u64 num, expect;
+		const u8 *b;
+		size_t max;
+
+		if (!json_to_u64(json, json_get_member(json, t, "value"),
+				 &expect))
+			abort();
+		b = tal_hexdata(tmpctx, json + bytes->start,
+				bytes->end - bytes->start);
+
+		max = tal_bytelen(b);
+		reason = NULL;
+		num = fromwire_bigsize(&b, &max);
+		if (err) {
+			assert(b == NULL);
+			assert(max == 0);
+			/* Map our errors to the test strings. */
+			if (json_tok_streq(json, err,
+					   "decoded varint is not canonical"))
+				assert(streq(reason, "not minimal encoded"));
+			else if (json_tok_streq(json, err, "unexpected EOF")
+				 || json_tok_streq(json, err, "EOF"))
+				assert(streq(reason, "less than encoding length"));
+			else
+				abort();
+		} else {
+			assert(b != NULL);
+			assert(num == expect);
+			assert(max == 0);
+		}
+	}
+}
+
+/* BOLT-EXPERIMENTAL #1:
+ *
+ * A correct implementation should pass against the following test vectors:
+ * ```json
+ * [
+ *     {
+ *         "name": "zero",
+ *         "value": 0,
+ *         "bytes": "00"
+ *     },
+ *     {
+ *         "name": "one byte high",
+ *         "value": 252,
+ *         "bytes": "fc"
+ *     },
+ *     {
+ *         "name": "two byte low",
+ *         "value": 253,
+ *         "bytes": "fd00fd"
+ *     },
+ *     {
+ *         "name": "two byte high",
+ *         "value": 65535,
+ *         "bytes": "fdffff"
+ *     },
+ *     {
+ *         "name": "four byte low",
+ *         "value": 65536,
+ *         "bytes": "fe00010000"
+ *     },
+ *     {
+ *         "name": "four byte high",
+ *         "value": 4294967295,
+ *         "bytes": "feffffffff"
+ *     },
+ *     {
+ *         "name": "eight byte low",
+ *         "value": 4294967296,
+ *         "bytes": "ff0000000100000000"
+ *     },
+ *     {
+ *         "name": "eight byte high",
+ *         "value": 18446744073709551615,
+ *         "bytes": "ffffffffffffffffff"
+ *     }
+ * ]
+ * ```
+ */
+static void test_encode(const char *json, const jsmntok_t toks[])
+{
+	size_t i;
+	const jsmntok_t *t;
+
+	json_for_each_arr(i, t, toks) {
+		const jsmntok_t *bytes = json_get_member(json, t, "bytes");
+		u64 num;
+		const u8 *expect;
+		u8 *b;
+
+		if (!json_to_u64(json, json_get_member(json, t, "value"),
+				 &num))
+			abort();
+		expect = tal_hexdata(tmpctx, json + bytes->start,
+				     bytes->end - bytes->start);
+
+		b = tal_arr(tmpctx, u8, 0);
+		towire_bigsize(&b, num);
+		assert(memeq(b, tal_bytelen(b), expect, tal_bytelen(expect)));
+	}
+}
+
+int main(int argc, char *argv[])
+{
+	char **lines, *json = NULL;
+	int test_count = 0;
+
+	setup_locale();
+	setup_tmpctx();
+
+	lines = tal_strsplit(tmpctx, grab_file(tmpctx, tal_fmt(tmpctx, "%s.c",
+							       argv[0])),
+			     "\n", STR_NO_EMPTY);
+
+	for (size_t i = 0; lines[i]; i++) {
+		const char *l = lines[i];
+		if (!strstarts(l, " * "))
+			continue;
+		l += 3;
+		if (streq(l, "```json"))
+			json = tal_strdup(tmpctx, "");
+		else if (streq(l, "```")) {
+			jsmn_parser parser;
+			jsmntok_t toks[500];
+
+			jsmn_init(&parser);
+			if (jsmn_parse(&parser, json, strlen(json),
+				       toks, ARRAY_SIZE(toks)) < 0)
+				abort();
+
+			switch (test_count) {
+			case 0:
+				test_decode(json, toks);
+				break;
+			case 1:
+				test_encode(json, toks);
+				break;
+			default:
+				abort();
+			}
+			test_count++;
+			json = NULL;
+		} else if (json)
+			tal_append_fmt(&json, "%s", l);
+	}
+	assert(test_count == 2);
+	tal_free(tmpctx);
+}