From 8c560fe4939e351b49fff7f38773a4afb860055c Mon Sep 17 00:00:00 2001
From: Lars Wirzenius <liw@liw.fi>
Date: Sat, 31 Oct 2009 18:04:25 +0200
Subject: Added assert command.

---
 Makefile |  2 +-
 assert   | 89 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 assert.1 | 34 +++++++++++++++++++++++++
 3 files changed, 124 insertions(+), 1 deletion(-)
 create mode 100755 assert
 create mode 100644 assert.1

diff --git a/Makefile b/Makefile
index 6d74fce..29c55cb 100644
--- a/Makefile
+++ b/Makefile
@@ -5,7 +5,7 @@ mandir = $(sharedir)/man
 man1dir = $(mandir)/man1
 
 progs = corrupt isascii
-scripts = do-until errno minimify onerror
+scripts = assert do-until errno minimify onerror
 
 CFLAGS = -Wall -O2 --std=gnu99
 
diff --git a/assert b/assert
new file mode 100755
index 0000000..4b31b5d
--- /dev/null
+++ b/assert
@@ -0,0 +1,89 @@
+#!/usr/bin/python
+
+
+import gnomevfs
+import optparse
+import os
+import subprocess
+import sys
+
+
+def setup_option_parser():
+    parser = optparse.OptionParser()
+    
+    parser.add_option("--file", metavar="FILE",
+                      help="Report FILE as being failing the assertion.")
+    
+    return parser
+
+
+def equal(options, args):
+    return args[0] == args[1], "%s != %s" % (repr(args[0]), repr(args[1]))
+
+
+def mime_type_is(options, args):
+    wanted_type = args[0]
+    args = args[1:]
+    for arg in args:
+        uri = gnomevfs.get_uri_from_local_path(os.path.abspath(arg))
+        actual_type = gnomevfs.get_mime_type(uri)
+        if actual_type != wanted_type:
+            options.file = arg
+            return False, "%s != %s" % (wanted_type, actual_type)
+    return True, None
+
+
+def file_type_is(options, args):
+    wanted_type = args[0]
+    filenames = args[1:]
+    for filename in filenames:
+        p = subprocess.Popen(["file", "-0", filename], stdout=subprocess.PIPE)
+        stdout, stderr = p.communicate()
+        if p.returncode == 0:
+            filename, actual_type = stdout.split("\0")
+            actual_type = actual_type.strip()
+            if actual_type != wanted_type:
+                return False, "%s != %s" % (wanted_type, actual_type)
+    return True, None
+
+
+def main():
+    parser = setup_option_parser()
+    options, args = parser.parse_args()
+    
+    opers = {
+        "equal": (2, 2, equal),
+        "file-type-is": (2, None, file_type_is),
+        "mime-type-is": (2, None, mime_type_is),
+    }
+    
+    if not args:
+        raise Exception("No operation on command line.")
+    elif args[0] in opers:
+        name = args[0]
+        args = args[1:]
+        min_count, max_count, func = opers[name]
+        if (len(args) < min_count or 
+            (max_count is not None and len(args) > max_count)):
+            raise Exception("Operation %s must have %d..%d "
+                            "arguments (got %d)." %
+                            (name, min_count, max_count or "infinity", 
+                             len(args)))
+        ok, msg = func(options, args)
+        if not ok:
+            parts = []
+            if options.file:
+                parts.append("%s: " % options.file)
+            parts.append("Assertion failed: ")
+            parts.append(msg or " ".join(sys.argv[1:]))
+            raise Exception("".join(parts))
+    else:
+        raise Exception("Unknown operation '%s'." % args[0])
+
+
+if __name__ == "__main__":
+    try:
+        main()
+    except Exception, e:
+        sys.stderr.write("%s\n" % str(e))
+        sys.exit(1)
diff --git a/assert.1 b/assert.1
new file mode 100644
index 0000000..c555482
--- /dev/null
+++ b/assert.1
@@ -0,0 +1,34 @@
+.\" assert.1 - manual page for the assert command
+.\" Copyright (C) 2009  Lars Wirzenius
+.\"
+.\" This program is free software: you can redistribute it and/or modify
+.\" it under the terms of the GNU General Public License as published by
+.\" the Free Software Foundation, either version 3 of the License, or
+.\" (at your option) any later version.
+.\"
+.\" This program is distributed in the hope that it will be useful,
+.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
+.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+.\" GNU General Public License for more details.
+.\"
+.\" You should have received a copy of the GNU General Public License
+.\" along with this program.  If not, see <http://www.gnu.org/licenses/>.
+.\"
+.TH ASSERT 1
+.SH NAME
+assert \- make sure given conditions are true
+.SH SYNOPSIS
+.B assert
+.RI [ --file =\fIFILE\fR]
+.SH DESCRIPTION
+.B assert
+checks that specific conditions are true.
+At the moment, it can check that a file has a given type (MIME or file(1)).
+.SH EXAMPLE
+The following command checks that the file NEWS has the MIME type text/plain.
+.sp 1
+.ti +4
+.nf
+assert mime-type-is text/plain NEWS
+.fi
+
-- 
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