Allow comments in test data files
diff --git a/tests/scripts/generate_code.pl b/tests/scripts/generate_code.pl
index e13a2d0..750b68b 100755
--- a/tests/scripts/generate_code.pl
+++ b/tests/scripts/generate_code.pl
@@ -1,5 +1,26 @@
#!/usr/bin/env perl
#
+# A test data file consists of a sequence of paragraphs separated by
+# a single empty line. Line breaks may be in Unix (LF) or Windows (CRLF)
+# format. Lines starting with the character '#' are ignored
+# (the parser behaves as if they were not present).
+#
+# Each paragraph describes one test case and must consist of: (1) one
+# line which is the test case name; (2) an optional line starting with
+# the 11-character prefix "depends_on:"; (3) a line containing the test
+# function to execute and its parameters.
+#
+# A depends_on: line consists of a list of compile-time options
+# separated by the character ':', with no whitespace. The test case
+# is executed only if this compilation option is enabled in config.h.
+#
+# The last line of each paragraph contains a test function name and
+# a list of parameters separated by the character ':'. Running the
+# test case calls this function with the specified parameters. Each
+# parameter may either be an integer written in decimal or hexadecimal,
+# or a string surrounded by double quotes which may not contain the
+# ':' character.
+#
use strict;