Added additional tests for TabArray

pangocffi/__init__.py

@@ -63,7 +63,7 @@ def _dlopen(dl_name: str, generated_ffi, names: List[str]):
 from .glyph_item_iter import GlyphItemIter  # noqa
 from .attribute import Attribute  # noqa
 from .attr_list import AttrList  # noqa
-from .tabarray import TabArray # noqa
+from .tab_array import TabArray # noqa
 from .layout_run import LayoutRun  # noqa
 from .layout_iter import LayoutIter  # noqa
 from .layout import Layout  # noqa

pangocffi/layout.py

@@ -165,12 +165,17 @@ def _del_attributes(self) -> None:
     :param attrs: a :class:`AttrList`
     """
 
-    def _get_tabs(self) -> TabArray:
+    def _get_tabs(self) -> Optional[TabArray]:
         tabs_pointer = pango.pango_layout_get_tabs(self._pointer)
-        return TabArray(tabs_pointer)
+        if tabs_pointer == ffi.NULL:
+            return None
+        return TabArray.from_pointer(tabs_pointer)
 
-    def _set_tabs(self, tabs: TabArray) -> None:
-        pango.pango_layout_set_tabs(self._pointer, tabs._pointer)
+    def _set_tabs(self, tabs: Optional[TabArray]) -> None:
+        if tabs is None:
+            pango.pango_layout_set_tabs(self._pointer, ffi.NULL)
+        else:
+            pango.pango_layout_set_tabs(self._pointer, tabs._pointer)
 
     tabs: str = property(_get_tabs, _set_tabs)
     """

tests/acceptance/test_tab_array.py

@@ -0,0 +1,79 @@
+import pangocffi
+from pangocffi import Layout, TabArray, TabAlign
+from tests.context_creator import ContextCreator
+import locale
+
+
+def test_tab_array_decimal_places():
+    """
+    In this test, we're aligning a list of labels and numbers.
+
+    The list of numbers is deliberately ugly, as ideally all numbers would be
+    given the same number of decimal places. But this test confirms that the
+    numbers are aligned at the comma.
+    """
+
+    width = 100
+    height = 100
+    # CFFIs and Contexts
+    context_creator = ContextCreator.create_pdf(
+        'tests/acceptance/output/tab-array-decimal-places.pdf', width, height
+    )
+    pangocairo = context_creator.pangocairo
+    cairo_context = context_creator.cairo_context
+
+    lines = [
+        ['Berlin', 891.3],
+        ['Hamburg', 755.2],
+        ['München', 310.7],
+        ['Stuttgart', 207.33],
+        ['Düsseldorf', 217.41],
+        ['Bremen', 326.7],
+        ['Dresden', 328.8],
+        ['Hannover', 204.007],
+        ['Wiesbaden', 203.9],
+        ['Kiel', 118.6],
+        ['Magdeburg', 201.012],
+        ['Mainz', 97.7],
+        ['Erfurt', 269.2],
+    ]
+
+    locale.setlocale(locale.LC_ALL, 'de_DE')
+
+    text = '\t<span font_weight="bold">Name</span>' \
+           '\t<span font_weight="bold"> Fläche (km²)</span>\n'
+    for line in lines:
+        text += "\t" + line[0]
+        text += "\t" + locale.format_string("%f", line[1])\
+            .rstrip('0').rstrip(',')
+        text += '\n'
+
+    # Using pangocairocffi, this would be `pangocairocffi.create_layout()` with
+    # a cairocffi context object.
+    layout = Layout.from_pointer(
+        pangocairo.pango_cairo_create_layout(cairo_context)
+    )
+
+    mm_to_inches = 72 / 25.4
+
+    layout.width = pangocffi.units_from_double(width * mm_to_inches)
+    layout.apply_markup(text)
+
+    # With this configuration, the tabs will align the text at 30mm and 70mm
+    # intervals. In more simple terms: The first items that are tabbed should
+    # appear right-aligned at the 30mm position, and all ',' (which will
+    # be part of a number) should appear at the 70mm position.
+    tabarray = TabArray()
+    tabarray.tabs = [
+        (TabAlign.RIGHT, pangocffi.units_from_double(30 * mm_to_inches)),
+        (TabAlign.DECIMAL, pangocffi.units_from_double(45 * mm_to_inches))
+    ]
+    decimal_point = [None, ',']
+    tabarray.decimal_point = decimal_point
+
+    layout.tabs = tabarray
+
+    # Using pangocairocffi, this would be `pangocairocffi.show_layout(layout)`
+    pangocairo.pango_cairo_show_layout(cairo_context, layout.pointer)
+
+    context_creator.close()

tests/functional/test_layout.py

@@ -5,6 +5,7 @@
     ffi,
     Attribute,
     AttrList,
+    TabArray,
 )
 import unittest
 
@@ -92,3 +93,17 @@ def test_set_attributes(self):
         # Resetting the attributes
         layout.attributes = None
         assert layout.attributes is None
+
+    def test_set_tabs(self):
+        context = Context()
+        layout = Layout(context)
+
+        assert layout.tabs is None
+
+        tab_array = TabArray()
+
+        layout.tabs = tab_array
+        assert layout.tabs is not None
+
+        layout.tabs = None
+        assert layout.tabs is None

tests/functional/test_tab_array.py

@@ -0,0 +1,43 @@
+from pangocffi import (
+    TabArray, TabAlign
+)
+import unittest
+
+
+class TestTabArray(unittest.TestCase):
+    def test_identity(self):
+        tab_array = TabArray()
+        assert len(tab_array) == 0
+        tabs = [(TabAlign.LEFT, 1), (TabAlign.LEFT, 10)]
+        tab_array.tabs = tabs
+        assert len(tab_array) == len(tabs)
+        assert tab_array.tabs == tabs
+
+        decimal_point = [':', ',']
+        tab_array.decimal_point = decimal_point
+        assert tab_array.decimal_point == decimal_point
+
+        assert tab_array.positions_in_pixels is False
+        tab_array.positions_in_pixels = True
+        assert tab_array.positions_in_pixels is True
+
+    def test_zero_size(self):
+        tab_array = TabArray()
+        assert len(tab_array) == 0
+        assert tab_array.tabs == []
+
+    def test_decimal_point_none(self):
+        tab_array = TabArray()
+
+        tabs = [(TabAlign.LEFT, 1), (TabAlign.LEFT, 10)]
+        tab_array.tabs = tabs
+        decimal_point = [None, None]
+        tab_array.decimal_point = decimal_point
+        assert tab_array.decimal_point == decimal_point
+
+    def test_decimal_point_index_error(self):
+        tab_array = TabArray()
+
+        tab_array.tabs = [(TabAlign.LEFT, 1), (TabAlign.LEFT, 10)]
+        with self.assertRaises(IndexError):
+            tab_array.decimal_point = [',']