Use -w option value.

Activates the -w option. Turns out we still have to fix
`get_wordlist_path` at it assumes that wordlists all end in
``.txt`` (which is not true).

diceware/__init__.py

@@ -163,7 +163,7 @@ def get_passphrase(options=None):
     if options is None:
         options = handle_options(args=[])
     if options.infile is None:
-        options.infile = open(get_wordlist_path("en_8k"), 'r')
+        options.infile = open(get_wordlist_path(options.wordlist), 'r')
     word_list = WordList(options.infile)
     rnd_source = get_random_sources()[options.randomsource]
     rnd = rnd_source(options)

tests/test_diceware.py

@@ -265,3 +265,12 @@ class TestDicewareModule(object):
         out, err = capsys.readouterr()
         specials = [x for x in out if x in SPECIAL_CHARS]
         assert len(specials) > 0
+
+    def test_main_wordlist(self, argv_handler, capsys, wordlists_dir):
+        # we can pick the wordlist we prefer
+        wordlists_dir.join('wordlist_foo.txt').write("foo\n")
+        wordlists_dir.join('wordlist_bar.asc').write("bar\n")
+        sys.argv = ['diceware', '-w', 'foo']
+        main()
+        out, err = capsys.readouterr()
+        assert out == 'FooFooFooFooFooFoo\n'