Merge pull request #27 from google/st-ligatures

Add tests for s-t and longs-t discretionary ligatures.

2 files changed, 39 insertions, 11 deletions

diff --git a/scripts/common_tests.py b/scripts/common_tests.py
index 926652a..1b015b8 100644
--- a/scripts/common_tests.py
+++ b/scripts/common_tests.py
@@ -1,3 +1,5 @@
+# coding=UTF-8
+#
 # Copyright 2015 Google Inc. All Rights Reserved.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
@@ -167,7 +169,7 @@ class TestDigitWidths(FontTest):
     """Tests the width of digits."""
 
     def setUp(self):
-        _, self.fonts = self.loaded_fonts
+        self.font_files, self.fonts = self.loaded_fonts
         self.digits = [
             'zero', 'one', 'two', 'three', 'four',
             'five', 'six', 'seven', 'eight', 'nine']
@@ -179,6 +181,17 @@ class TestDigitWidths(FontTest):
             widths = [hmtx_table[digit][0] for digit in self.digits]
             self.assertEqual(len(set(widths)), 1)
 
+    def test_superscript_digits(self):
+        """Tests that 'numr' features maps digits to Unicode superscripts."""
+        ascii_digits = '0123456789'
+        superscript_digits = u'⁰¹²³⁴⁵⁶⁷⁸⁹'
+        for font_file in self.font_files:
+            numr_glyphs = layout.get_advances(
+                ascii_digits, font_file, '--features=numr')
+            superscript_glyphs = layout.get_advances(
+                superscript_digits, font_file)
+            self.assertEqual(superscript_glyphs, numr_glyphs)
+
 
 class TestCharacterCoverage(FontTest):
     """Tests character coverage."""
@@ -232,6 +245,15 @@ class TestLigatures(FontTest):
             advances = layout.get_advances('ff', fontfile)
             self.assertEqual(len(advances), 2)
 
+    def test_st_ligatures(self):
+        """Tests that st ligatures are formed by dlig."""
+        for fontfile in self.fontfiles:
+            for combination in [u'st', u'ſt']:
+                normal = layout.get_glyphs(combination, fontfile)
+                ligated = layout.get_glyphs(
+                    combination, fontfile, '--features=dlig')
+                self.assertTrue(len(normal) == 2 and len(ligated) == 1)
+
 
 class TestVerticalMetrics(FontTest):
     """Test the vertical metrics of fonts."""
diff --git a/scripts/layout.py b/scripts/layout.py
index 91cf8e8..343f359 100644
--- a/scripts/layout.py
+++ b/scripts/layout.py
@@ -18,35 +18,41 @@ import json
 
 from nototools import render
 
-def _run_harfbuzz(text, font, language):
+def _run_harfbuzz(text, font, language, extra_parameters=None):
     """Run harfbuzz on some text and return the shaped list."""
-    hb_output = render.run_harfbuzz_on_text(text, font, language)
+    try:
+        # if extra_parameters is a string, split it into a list
+        extra_parameters = extra_parameters.split(' ')
+    except AttributeError:
+        pass
+    hb_output = render.run_harfbuzz_on_text(
+        text, font, language, extra_parameters)
     return json.loads(hb_output)
 
 
 _advance_cache = {}
-def get_advances(text, font):
+def get_advances(text, font, extra_parameters=None):
     """Get a list of horizontal advances for text rendered in a font."""
     try:
-        return _advance_cache[(text, font)]
+        return _advance_cache[(text, font, extra_parameters)]
     except KeyError:
         pass
 
-    hb_output = _run_harfbuzz(text, font, None)
+    hb_output = _run_harfbuzz(text, font, None, extra_parameters)
     advances = [glyph['ax'] for glyph in hb_output]
-    _advance_cache[(text, font)] = advances
+    _advance_cache[(text, font, extra_parameters)] = advances
     return advances
 
 
 _shape_cache = {}
-def get_glyphs(text, font):
+def get_glyphs(text, font, extra_parameters=None):
     """Get a list of shaped glyphs for text rendered in a font."""
     try:
-        return _shape_cache[(text, font)]
+        return _shape_cache[(text, font, extra_parameters)]
     except KeyError:
         pass
 
-    hb_output = _run_harfbuzz(text, font, None)
+    hb_output = _run_harfbuzz(text, font, None, extra_parameters)
     shapes = [glyph['g'] for glyph in hb_output]
-    _shape_cache[(text, font)] = shapes
+    _shape_cache[(text, font, extra_parameters)] = shapes
     return shapes