This test modifies the installed font file with block_device_writer.
FontManagerService should detect it and remove the modified file.
Bug: 176939176
Test: atest ApkVerityTest
Test: atest UpdatableSystemFontTest
Change-Id: I7da3f2911459619d5d56a94e091b912d67cb27d3
This test:
(1) signs a font file with the test key.
(2) side-loads the test cert to the device under test.
(3) verifies that the signed font file can be installed.
The device must be rootable for doing step (2).
Bug: 176939176
Test: atest UpdatableSystemFontTest
Change-Id: I7a9b614aa3c77589c3495b663cb76056ba657006