this adds three new tests for varLib.build:
1) the input designspace contains a single 'weight' axis with <map>
elements that modify the normalization mapping;
2) the input designspace contains two 'weight' and 'width' axes both
with <map> elements, but the 'width' axis only contains identity
mappings;
3) the input designspace contains two 'weight' and 'width' axes, but
only one axis ('weight') has some <map> elements.
The master interpolatable ttx files for 'TestFamily3' are a subset of
Noto Sans containing only the letters to type the word "FontTools".
Note: the `expect_ttx` test is passing, but the `check_ttx_dump` which ensures the TTX dump is the same after saving and reloading the font, is currently failing, as the "ValueRecordSize" count is None
```
--- /Users/cosimolupo/Documents/Github/fonttools/Tests/varLib/data/test_results/Build.ttx
+++ /var/folders/7k/fl5q53lj51g0d8hxdkrx9_z80000gn/T/tmpoBCAua/tmp1.ttx
@@ -174,8 +174,7 @@
<MVAR>
<Version value="0x00010000"/>
<Reserved value="0"/>
- <ValueRecordSize value="8"/>
- <!-- ValueRecordCount=2 -->
+ <ValueRecordSize value="None"/>
<VarStore Format="1">
<Format value="1"/>
<VarRegionList>
```
Ie. they don't specify any unknown axes, and location is within
axis minimum/maximum. We also allow master / instance locations
to not specify some axes, and we fill in the axis default for those.
We do not accept nonstandard axes if <axes> element is not present.
Breaks one test. Needs updated expectations.
Soon we'll be generating avar as well and all will be better, much better.
These originated from TTFs that were built from the test UFO masters using fontmake v1.2.0 with the command `fontmake -m BuildTest.designspace -o variable`
