pmbootstrap init: Wizard for new port device- and linux-packages (#821)

* pmbootstrap init: Generate new port device- and linux-package
* adds `pmbootstrap aportgen device-*` and
  `pmbootstrap aportgen linux-*`
* ask for confirmation when selecting a non-existing device
* generate the packages directly from init
* refactor aportgen code
* fixed some easy things in the linux- APKBUILD (more to come in
  follow-up PRs!)

Testing:
* Test all questions to the user from pmb.config.init and pmb.aportgen.device
  (except for the timezone question, because we would need to monkeypatch the
  os.path.exists() function, which messes up pytest, so we'd need to refactor
  the timezone function to be more testsuite friendly first)
* Run the device wizard in a testcase a few times and check the output, that
  pmbootstrap.aportgen.device and pmbootstrap.aportgen.linux create by parsing
  the resulting APKBUILDs and deviceinfo and checking its contents.
* Build the generated device package once in the same testcase

Thanks a lot to @drebrez for all the help with this one:
<https://github.com/postmarketOS/pmbootstrap/pull/821>

See also the updated porting guide:
<https://wiki.postmarketos.org/wiki/Porting_to_a_new_device>

test/test_questions.py

@@ -0,0 +1,133 @@
+"""
+Copyright 2017 Oliver Smith
+
+This file is part of pmbootstrap.
+
+pmbootstrap 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.
+
+pmbootstrap 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 pmbootstrap.  If not, see <http://www.gnu.org/licenses/>.
+"""
+import logging
+import os
+import pytest
+import sys
+
+# Import from parent directory
+sys.path.append(os.path.realpath(
+    os.path.join(os.path.dirname(__file__) + "/..")))
+import pmb.aportgen.device
+import pmb.config
+import pmb.config.init
+import pmb.helpers.logging
+
+
+@pytest.fixture
+def args(tmpdir, request):
+    import pmb.parse
+    sys.argv = ["pmbootstrap.py", "init"]
+    args = pmb.parse.arguments()
+    args.log = args.work + "/log_testsuite.txt"
+    pmb.helpers.logging.init(args)
+    request.addfinalizer(args.logfd.close)
+    return args
+
+
+def test_questions(args, monkeypatch, tmpdir):
+    #
+    # PREPARATION
+    #
+
+    # Use prepared answers
+    def fake_ask(args, question="Continue?", choices=["y", "n"], default="n",
+                 lowercase_answer=True, validation_regex=None):
+        answer = answers.pop(0)
+        logging.info("pmb.helpers.cli.ask: fake answer: " + answer)
+        return answer
+    monkeypatch.setattr(pmb.helpers.cli, "ask", fake_ask)
+
+    # Do not generate aports
+    def fake_generate(args, pkgname):
+        return
+    monkeypatch.setattr(pmb.aportgen, "generate", fake_generate)
+
+    # Self-test
+    answers = ["first", "second"]
+    assert pmb.helpers.cli.ask(args) == "first"
+    assert pmb.helpers.cli.ask(args) == "second"
+    assert len(answers) == 0
+
+    #
+    # SIMPLE QUESTIONS
+    #
+
+    # Booleans
+    functions = [pmb.aportgen.device.ask_for_keyboard,
+                 pmb.aportgen.device.ask_for_external_storage]
+    for func in functions:
+        answers = ["y", "n"]
+        assert func(args) is True
+        assert func(args) is False
+
+    # Strings
+    functions = [pmb.aportgen.device.ask_for_manufacturer,
+                 pmb.aportgen.device.ask_for_name]
+    for func in functions:
+        answers = ["Simple string answer"]
+        assert func(args) == "Simple string answer"
+
+    #
+    # QUESTIONS WITH ANSWER VERIFICATION
+    #
+
+    # Architecture
+    answers = ["invalid_arch", "aarch64"]
+    assert pmb.aportgen.device.ask_for_architecture(args) == "aarch64"
+
+    # Device
+    func = pmb.config.init.ask_for_device
+    answers = ["lg-mako"]
+    assert func(args) == ("lg-mako", True)
+
+    answers = ["whoops-typo", "n", "lg-mako"]
+    assert func(args) == ("lg-mako", True)
+
+    answers = ["new-device", "y"]
+    assert func(args) == ("new-device", False)
+
+    # Flash methods
+    func = pmb.aportgen.device.ask_for_flash_method
+    answers = ["invalid_flash_method", "fastboot"]
+    assert func(args) == "fastboot"
+
+    answers = ["0xffff"]
+    assert func(args) == "0xffff"
+
+    answers = ["heimdall", "invalid_type", "isorec"]
+    assert func(args) == "heimdall-isorec"
+
+    answers = ["heimdall", "bootimg"]
+    assert func(args) == "heimdall-bootimg"
+
+    # Keymaps
+    func = pmb.config.init.ask_for_keymaps
+    answers = ["invalid_keymap", "us/rx51_us"]
+    assert func(args, "nokia-rx51") == "us/rx51_us"
+    assert func(args, "lg-mako") == ""
+
+    # UI
+    answers = ["invalid_UI", "weston"]
+    assert pmb.config.init.ask_for_ui(args) == "weston"
+
+    # Work path
+    tmpdir = str(tmpdir)
+    answers = ["/dev/null", tmpdir]
+    assert pmb.config.init.ask_for_work_path(args) == tmpdir