ccanlint: add test case for metadata summary line on a single separate line.

tools/ccanlint/tests/info_summary_single_line.c

+#include <tools/ccanlint/ccanlint.h>
+#include <tools/tools.h>
+#include <stdio.h>
+#include <ccan/talloc/talloc.h>
+#include <ccan/str/str.h>
+
+/* Summary line is form '<identifier> - ' (spaces for 'struct foo -') */
+/* slightly modified from doc_extract-core.c */
+static unsigned int is_summary_line(const char *line)
+{
+	unsigned int id_len;
+
+	id_len = strspn(line, IDENT_CHARS" *");
+	if (id_len == 0)
+		return 0;
+	if (strspn(line, " ") == id_len)
+		return 0;
+	if (!strstarts(line + id_len-1, " - "))
+		return 0;
+	return id_len - 1;
+}
+
+static void check_info_summary_single_line(struct manifest *m,
+					   bool keep,
+					   unsigned int *timeleft,
+					   struct score *score)
+{
+	int i = 0;
+	get_ccan_line_info(m->info_file);
+	score->total = 1;
+	for (i = 0; i < m->info_file->num_lines; ++i) {
+		if (is_summary_line(m->info_file->lines[i])) {
+			if (strspn(m->info_file->lines[i+1], " *") == strlen(m->info_file->lines[i+1])) {
+				/* valid summary line */
+				score->error = NULL;
+				score->pass = true;
+				score->score = 1;
+			} else {
+				/* invalid summary line - line following summary line should be empty */
+				score->pass = false;
+				score->score = 0;
+				score->error = "invalid summary line - not on a single line:";
+				score_file_error(score, m->info_file, i+1, "summary is not on a single line");
+			}
+			break;
+		}
+	}
+}
+
+
+struct ccanlint info_summary_single_line = {
+	.key = "info_summary_single_line",
+	.name = "Module has a single line summary in _info",
+	.check = check_info_summary_single_line,
+	.needs = "info_exists"
+};
+
+REGISTER_TEST(info_summary_single_line);