tests: move/rename/cleanup vspec based tests

The main motivation is to being able to use normal/other pytest based
tests.

Therefore this moves everything from conftest into test_integration
itself.

Makefile

@@ -1,5 +1,5 @@
 test:
-	pytest test_*.py
+	pytest
 
 test_nvim:
 	VSPEC_VIM=nvim pytest test_*.py

setup.cfg

@@ -1,2 +1,5 @@
+[tool:pytest]
+testpaths = test
+
 [flake8]
 max-line-length = 100

test/test_integration.py

@@ -0,0 +1,62 @@
+"""Runs tests from ./vspec in vim-vspec."""
+import os
+import subprocess
+import urllib.request
+import zipfile
+
+import pytest
+
+vspec_version = '1.8.1'
+
+VSPEC_URL = 'https://github.com/kana/vim-vspec/archive/%s.zip' % vspec_version
+root = os.path.dirname(os.path.dirname(__file__))
+CACHE_FOLDER = os.path.join(root, 'build')
+VSPEC_FOLDER = os.path.join(CACHE_FOLDER, 'vim-vspec-%s' % vspec_version)
+VSPEC_RUNNER = os.path.join(VSPEC_FOLDER, 'bin/vspec')
+TEST_DIR = os.path.join(root, 'test', 'vspec')
+
+
+@pytest.fixture(scope='session')
+def install_vspec(request):
+    if not os.path.isdir(CACHE_FOLDER):
+        os.mkdir(CACHE_FOLDER)
+
+    if not os.path.exists(VSPEC_FOLDER):
+        name, hdrs = urllib.request.urlretrieve(VSPEC_URL)
+        z = zipfile.ZipFile(name)
+        for n in z.namelist():
+            dest = os.path.join(CACHE_FOLDER, n)
+            destdir = os.path.dirname(dest)
+            if not os.path.isdir(destdir):
+                os.makedirs(destdir)
+            data = z.read(n)
+            if not os.path.isdir(dest):
+                with open(dest, 'wb') as f:
+                    f.write(data)
+        z.close()
+        os.chmod(VSPEC_RUNNER, 0o777)
+
+
+def get_vspec_tests():
+    for f in os.listdir(TEST_DIR):
+        yield os.path.relpath(os.path.join(TEST_DIR, f))
+
+
+@pytest.mark.parametrize('path', get_vspec_tests())
+def test_integration(install_vspec, path):
+    output = subprocess.check_output(
+        [VSPEC_RUNNER, '.', VSPEC_FOLDER, os.path.relpath(path, root)],
+        cwd=root,
+    )
+    had_ok = False
+    for line in output.splitlines():
+        if (line.startswith(b'not ok') or
+                line.startswith(b'Error') or
+                line.startswith(b'Bail out!')):
+            pytest.fail("{0} failed:\n{1}".format(
+                path, output.decode('utf-8')), pytrace=False)
+        if not had_ok and line.startswith(b'ok'):
+            had_ok = True
+    if not had_ok:
+        pytest.fail("{0} failed: no 'ok' found:\n{1}".format(
+            path, output.decode('utf-8')), pytrace=False)