import: pypi: Do not parse optional requirements from source.

* guix/import/pypi.scm: Export PARSE-REQUIRES.TXT.
(clean-requirement): Move procedure to the top level.
(guess-requirements): Move the READ-REQUIREMENTS procedure to the top level,
and rename it to PARSE-REQUIRES.TXT.  Move the CLEAN-REQUIREMENT procedure to
the top level.  Move the COMMENT? functions inside the PARSE-REQUIRES.TXT
procedure.
(parse-requires.txt): Add a SECTION-HEADER? predicate, and use it to prevent
parsing optional requirements.

* tests/pypi.scm (test-requires-with-sections): New variable.
("parse-requires.txt, with sections"): New test.

1 files changed, 14 insertions, 0 deletions

diff --git a/tests/pypi.scm b/tests/pypi.scm
index 6df69073dc..03455ba6be 100644
--- a/tests/pypi.scm
+++ b/tests/pypi.scm
@@ -62,6 +62,14 @@ bar
 baz > 13.37
 ")
 
+(define test-requires-with-sections "\
+foo ~= 3
+bar != 2
+
+[test]
+pytest (>=2.5.0)
+")
+
 (define test-metadata
   "{
   \"run_requires\": [
@@ -101,6 +109,12 @@ baz > 13.37
                     (uri (list "https://bitheap.org/cram/cram-0.7.tar.gz"
                                (pypi-uri "cram" "0.7"))))))))
 
+(test-equal "parse-requires.txt, with sections"
+  '("foo" "bar")
+  (mock ((ice-9 ports) call-with-input-file
+         call-with-input-string)
+        (parse-requires.txt test-requires-with-sections)))
+
 (test-assert "pypi->guix-package"
   ;; Replace network resources with sample data.
     (mock ((guix import utils) url-fetch