build-aux: Write failed corpus test emails to filesystem.

* build-aux/test-corpus.scm.in: Import (rnrs io ports), (srfi
srfi-26), (srfi srfi-28), (srfi srfi-171), (ice-9 ftw) and (ice-9
match).
(%fail-directory): New variable.
(directory-files, write-failed-email): New function.
Write failed corpus test emails to a "fail directory" specified on the
command line.

1 files changed, 65 insertions, 22 deletions

diff --git a/build-aux/test-corpus.scm.in b/build-aux/test-corpus.scm.in
index 0920113..9e66132 100644
--- a/build-aux/test-corpus.scm.in
+++ b/build-aux/test-corpus.scm.in
@@ -28,27 +28,70 @@
 
 ;;; Code:
 
-(use-modules (ice-9 ftw)
+(use-modules (rnrs io ports)
+             (srfi srfi-26)
+             (srfi srfi-28)
+             (srfi srfi-171)
+             (ice-9 ftw)
+             (ice-9 match)
              (email email))
 
-(for-each (lambda (mbox)
-            (display mbox)
-            (newline)
-            (call-with-input-file mbox
-              (lambda (port)
-                (for-each parse-email (mbox->emails port)))))
-          (file-system-fold (const #t)
-                            (lambda (name stat result)
-                              (if (string-suffix? ".mbox" name)
-                                  (cons name result)
-                                  result))
-                            (lambda (name stat result)
-                              result)
-                            (lambda (name stat result)
-                              result)
-                            (lambda (name stat result)
-                              result)
-                            (lambda (name stat errno result)
-                              (error (strerror errno) name))
-                            '()
-                            "."))
+(define %fail-directory
+  (match (command-line)
+    ((_ fail-directory) fail-directory)
+    ((arg0 _ ...)
+     (scm-error 'misc-error
+                #f
+                "Usage: ~A fail-directory"
+                (list arg0)
+                #f))))
+
+(define (directory-files directory)
+  "Return files in DIRECTORY."
+  (scandir directory (lambda (filename)
+                       (not (member filename (list "." ".."))))))
+
+(define (write-failed-email corpus mbox index email)
+  "Write EMAIL, the INDEXth email in MBOX of CORPUS, for which
+parse-email fails to fail directory."
+  (display (format "Failed on index ~a of ~a/~a~%" index corpus mbox))
+  (call-with-output-file (format "~a/~a_~a_~a"
+                                 %fail-directory
+                                 corpus
+                                 (basename mbox ".mbox")
+                                 index)
+    (cut put-bytevector <> email)))
+
+(define (test-corpus corpus)
+  "Test CORPUS, a directory containing mbox files."
+  (for-each (lambda (mbox)
+              (let ((mbox-path (string-append corpus "/" mbox)))
+                (display (format "~a~%" mbox-path))
+                (call-with-input-file mbox-path
+                  (lambda (port)
+                    (list-transduce (compose (tenumerate)
+                                             (tmap (match-lambda
+                                                     ((index . bv)
+                                                      (catch #t
+                                                        (lambda ()
+                                                          (parse-email bv))
+                                                        (lambda _
+                                                          (write-failed-email corpus mbox index bv)))))))
+                                    (const #t)
+                                    (mbox->emails port))))))
+            (directory-files corpus)))
+
+;; If fail directory exists, delete its contents. Else, create it.
+(if (file-exists? %fail-directory)
+    (for-each (lambda (file)
+                (delete-file (string-append %fail-directory "/" file)))
+              (directory-files %fail-directory))
+    (mkdir %fail-directory))
+
+;; Test corpora.
+(test-corpus "guix-commits")
+(test-corpus "guix-patches")
+
+;; If fail directory has any emails, then error out.
+(unless (null? (directory-files %fail-directory))
+  (error "Corpus test failed for some messages"))