Make standarddir work on HaikuOS

For some reason, it returns an empty DataLocation.

qutebrowser/utils/standarddir.py

@@ -20,6 +20,7 @@
 """Utilities to get and initialize data/config paths."""
 
 import os
+import sys
 import shutil
 import os.path
 import contextlib
@@ -106,6 +107,10 @@ def _init_data(args):
         if utils.is_windows:
             app_data_path = _writable_location(QStandardPaths.AppDataLocation)
             path = os.path.join(app_data_path, 'data')
+        elif sys.platform.startswith('haiku'):
+            # HaikuOS returns an empty value for AppDataLocation
+            config_path = _writable_location(QStandardPaths.ConfigLocation)
+            path = os.path.join(config_path, 'data')
         else:
             path = _writable_location(typ)
     _create(path)

tests/unit/utils/test_standarddir.py

@@ -103,6 +103,20 @@ def test_fake_windows(tmpdir, monkeypatch, what):
     assert func() == str(tmpdir / APPNAME / what)
 
 
+def test_fake_haiku(tmpdir, monkeypatch):
+    """Test getting data dir on HaikuOS."""
+    locations = {
+        QStandardPaths.DataLocation: '',
+        QStandardPaths.ConfigLocation: str(tmpdir / 'config' / APPNAME),
+    }
+    monkeypatch.setattr(standarddir.QStandardPaths, 'writableLocation',
+                        locations.get)
+    monkeypatch.setattr(standarddir.sys, 'platform', 'haiku1')
+
+    standarddir._init_data(args=None)
+    assert standarddir.data() == str(tmpdir / 'config' / APPNAME / 'data')
+
+
 class TestWritableLocation:
 
     """Tests for _writable_location."""