instancer_test: make new test font with FeatureVariations

instead of reading off existing FeatureVars.ttx test file.
This gives us more flexibility to add more tests, and keeps the input
values closer to the expected results

Tests/varLib/instancer_test.py

@@ -10,6 +10,7 @@ from fontTools import varLib
 from fontTools.varLib import instancer
 from fontTools.varLib.mvar import MVAR_ENTRIES
 from fontTools.varLib import builder
+from fontTools.varLib import featureVars
 from fontTools.varLib import models
 from fontTools.misc.loggingTools import CapturingLogHandler
 import collections
@@ -1149,23 +1150,6 @@ class InstantiateVariableFontTest(object):
         assert _dump_ttx(instance) == expected
 
 
-@pytest.fixture
-def varfont3():
-    # The test file "Tests/varLib/data/test_results/FeatureVars.ttx" contains
-    # a GSUB.FeatureVariations table built from conditional rules specified in
-    # "Tests/varLib/data/FeatureVars.designspace" file, which are equivalent to:
-    #
-    #   conditionalSubstitutions = [
-    #       ([{"wght": (0.20886, 1.0)}], {"uni0024": "uni0024.nostroke"}),
-    #       ([{"cntr": (0.75, 1.0)}], {"uni0041": "uni0061"}),
-    #       ([{"wght": (-1.0, -0.45654), "cntr": (0, 0.25)}], {"uni0061": "uni0041"}),
-    #   ]
-    ttx = os.path.join(TESTDATA, "test_results", "FeatureVars.ttx")
-    font = ttLib.TTFont(recalcBBoxes=False, recalcTimestamp=False)
-    font.importXML(ttx)
-    return font
-
-
 def _conditionSetAsDict(conditionSet, axisOrder):
     result = {}
     for cond in conditionSet.ConditionTable:
@@ -1184,6 +1168,29 @@ def _getSubstitutions(gsub, lookupIndices):
     return subs
 
 
+def makeFeatureVarsFont(conditionalSubstitutions):
+    axes = set()
+    glyphs = set()
+    for region, substitutions in conditionalSubstitutions:
+        for box in region:
+            axes.update(box.keys())
+        glyphs.update(*substitutions.items())
+
+    varfont = ttLib.TTFont()
+    varfont.setGlyphOrder(sorted(glyphs))
+
+    fvar = varfont["fvar"] = ttLib.newTable("fvar")
+    fvar.axes = []
+    for axisTag in sorted(axes):
+        axis = _f_v_a_r.Axis()
+        axis.axisTag = Tag(axisTag)
+        fvar.axes.append(axis)
+
+    featureVars.addFeatureVariations(varfont, conditionalSubstitutions)
+
+    return varfont
+
+
 class InstantiateFeatureVariationsTest(object):
     @pytest.mark.parametrize(
         "location, appliedSubs, expectedRecords",
@@ -1227,8 +1234,17 @@ class InstantiateFeatureVariationsTest(object):
             ),
         ],
     )
-    def test_partial_instance(self, varfont3, location, appliedSubs, expectedRecords):
+    def test_partial_instance(self, location, appliedSubs, expectedRecords):
-        font = varfont3
+        font = makeFeatureVarsFont(
+            [
+                ([{"wght": (0.20886, 1.0)}], {"uni0024": "uni0024.nostroke"}),
+                ([{"cntr": (0.75, 1.0)}], {"uni0041": "uni0061"}),
+                (
+                    [{"wght": (-1.0, -0.45654), "cntr": (0, 0.25)}],
+                    {"uni0061": "uni0041"},
+                ),
+            ]
+        )
 
         instancer.instantiateFeatureVariations(font, location)
 
@@ -1268,8 +1284,17 @@ class InstantiateFeatureVariationsTest(object):
             ({"wght": -1.0, "cntr": 0.3}, None),
         ],
     )
-    def test_full_instance(self, varfont3, location, appliedSubs):
+    def test_full_instance(self, location, appliedSubs):
-        font = varfont3
+        font = makeFeatureVarsFont(
+            [
+                ([{"wght": (0.20886, 1.0)}], {"uni0024": "uni0024.nostroke"}),
+                ([{"cntr": (0.75, 1.0)}], {"uni0041": "uni0061"}),
+                (
+                    [{"wght": (-1.0, -0.45654), "cntr": (0, 0.25)}],
+                    {"uni0061": "uni0041"},
+                ),
+            ]
+        )
 
         instancer.instantiateFeatureVariations(font, location)
 
@@ -1282,14 +1307,22 @@ class InstantiateFeatureVariationsTest(object):
         else:
             assert not gsub.FeatureList.FeatureRecord
 
-    def test_unsupported_condition_format(self, varfont3):
+    def test_unsupported_condition_format(self):
-        gsub = varfont3["GSUB"].table
+        font = makeFeatureVarsFont(
+            [
+                (
+                    [{"wdth": (-1.0, -0.5), "wght": (0.5, 1.0)}],
+                    {"dollar": "dollar.nostroke"},
+                )
+            ]
+        )
+        gsub = font["GSUB"].table
         featureVariations = gsub.FeatureVariations
         rec1 = featureVariations.FeatureVariationRecord[0]
         rec1.ConditionSet.ConditionTable[0].Format = 2
 
         with CapturingLogHandler("fontTools.varLib.instancer", "WARNING") as captor:
-            instancer.instantiateFeatureVariations(varfont3, {"wght": 0})
+            instancer.instantiateFeatureVariations(font, {"wght": 0})
 
         captor.assertRegex(
             r"Condition table 0 of FeatureVariationRecord 0 "