ttx tests: add tests for Options, ttCompile, ttList, main

Tests/ttx/ttx_test.py

@@ -1,14 +1,17 @@
 from __future__ import print_function, division, absolute_import
 from fontTools.misc.py23 import *
 from fontTools.misc.testTools import parseXML
+from fontTools.misc.timeTools import timestampSinceEpoch
+from fontTools.ttLib import TTFont, TTLibError
 from fontTools import ttx
 import getopt
+import logging
 import os
 import shutil
-import sys
 import tempfile
 import unittest
 
+import pytest
 
 class TTXTest(unittest.TestCase):
     def __init__(self, methodName):
@@ -263,5 +266,565 @@ class TTXTest(unittest.TestCase):
         self.assertIsNone(ttx.guessFileType(font_path))
 
 
-if __name__ == "__main__":
+# -----------------------
-    sys.exit(unittest.main())
+# ttx.Options class tests
+# -----------------------
+
+
+def test_ttx_options_class_defaults():
+    tto = ttx.Options([(None, None)], 1)
+    assert tto.listTables is False
+    assert tto.outputDir is None
+    assert tto.outputFile is None
+    assert tto.overWrite is False
+    assert tto.verbose is False
+    assert tto.quiet is False
+    assert tto.splitTables is False
+    assert tto.splitGlyphs is False
+    assert tto.disassembleInstructions is True
+    assert tto.mergeFile is None
+    assert tto.recalcBBoxes is True
+    assert tto.allowVID is False
+    assert tto.ignoreDecompileErrors is True
+    assert tto.bitmapGlyphDataFormat == "raw"
+    assert tto.unicodedata is None
+    assert tto.newlinestr is None
+    assert tto.recalcTimestamp is False
+    assert tto.flavor is None
+    assert tto.useZopfli is False
+    assert tto.onlyTables == []
+    assert tto.skipTables == []
+    assert tto.fontNumber == -1
+    assert tto.logLevel == logging.INFO
+
+
+def test_ttx_options_class_flag_h(capsys):
+    with pytest.raises(SystemExit):
+        ttx.Options([("-h", None)], 1)
+
+    out, err = capsys.readouterr()
+    assert "TTX -- From OpenType To XML And Back" in out
+
+
+def test_ttx_options_class_flag_version(capsys):
+    with pytest.raises(SystemExit):
+        ttx.Options([("--version", None)], 1)
+
+    out, err = capsys.readouterr()
+    version_list = out.split(".")
+    assert len(version_list) >= 3
+    assert version_list[0].isdigit()
+    assert version_list[1].isdigit()
+    assert version_list[2].isdigit()
+
+
+def test_ttx_options_class_flag_d_goodpath(tmpdir):
+    temp_dir_path = str(tmpdir)
+    tto = ttx.Options([("-d", temp_dir_path)], 1)
+    assert tto.outputDir == temp_dir_path
+
+
+def test_ttx_options_class_flag_d_badpath():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-d", "bogusdir")], 1)
+
+
+def test_ttx_options_class_flag_o():
+    tto = ttx.Options([("-o", "testfile.ttx")], 1)
+    assert tto.outputFile == "testfile.ttx"
+
+
+def test_ttx_options_class_flag_f():
+    tto = ttx.Options([("-f", "")], 1)
+    assert tto.overWrite is True
+
+
+def test_ttx_options_class_flag_v():
+    tto = ttx.Options([("-v", "")], 1)
+    assert tto.verbose is True
+    assert tto.logLevel == logging.DEBUG
+
+
+def test_ttx_options_class_flag_q():
+    tto = ttx.Options([("-q", "")], 1)
+    assert tto.quiet is True
+    assert tto.logLevel == logging.WARNING
+
+
+def test_ttx_options_class_flag_l():
+    tto = ttx.Options([("-l", "")], 1)
+    assert tto.listTables is True
+
+
+def test_ttx_options_class_flag_t_nopadding():
+    tto = ttx.Options([("-t", "CFF2")], 1)
+    assert len(tto.onlyTables) == 1
+    assert tto.onlyTables[0] == "CFF2"
+
+
+def test_ttx_options_class_flag_t_withpadding():
+    tto = ttx.Options([("-t", "CFF")], 1)
+    assert len(tto.onlyTables) == 1
+    assert tto.onlyTables[0] == "CFF "
+
+
+def test_ttx_options_class_flag_s():
+    tto = ttx.Options([("-s", "")], 1)
+    assert tto.splitTables is True
+    assert tto.splitGlyphs is False
+
+
+def test_ttx_options_class_flag_g():
+    tto = ttx.Options([("-g", "")], 1)
+    assert tto.splitGlyphs is True
+    assert tto.splitTables is True
+
+
+def test_ttx_options_class_flag_i():
+    tto = ttx.Options([("-i", "")], 1)
+    assert tto.disassembleInstructions is False
+
+
+def test_ttx_options_class_flag_z_validoptions():
+    valid_options = ('raw', 'row', 'bitwise', 'extfile')
+    for option in valid_options:
+        tto = ttx.Options([("-z", option)], 1)
+        assert tto.bitmapGlyphDataFormat == option
+
+
+def test_ttx_options_class_flag_z_invalidoption():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-z", "bogus")], 1)
+
+
+def test_ttx_options_class_flag_y_validvalue():
+    tto = ttx.Options([("-y", "1")], 1)
+    assert tto.fontNumber == 1
+
+
+# TODO: fix this with a check in the ttx module: str.isdigit()
+def test_ttx_options_class_flag_y_invalidvalue():
+    with pytest.raises(ValueError):
+        ttx.Options([("-y", "A")], 1)
+
+
+def test_ttx_options_class_flag_m():
+    tto = ttx.Options([("-m", "testfont.ttf")], 1)
+    assert tto.mergeFile == "testfont.ttf"
+
+
+def test_ttx_options_class_flag_b():
+    tto = ttx.Options([("-b", "")], 1)
+    assert tto.recalcBBoxes is False
+
+
+def test_ttx_options_class_flag_a():
+    tto = ttx.Options([("-a", "")], 1)
+    assert tto.allowVID is True
+
+
+def test_ttx_options_class_flag_e():
+    tto = ttx.Options([("-e", "")], 1)
+    assert tto.ignoreDecompileErrors is False
+
+
+def test_ttx_options_class_flag_unicodedata():
+    tto = ttx.Options([("--unicodedata", "UnicodeData.txt")], 1)
+    assert tto.unicodedata == "UnicodeData.txt"
+
+
+def test_ttx_options_class_flag_newline_lf():
+    tto = ttx.Options([("--newline", "LF")], 1)
+    assert tto.newlinestr == "\n"
+
+
+def test_ttx_options_class_flag_newline_cr():
+    tto = ttx.Options([("--newline", "CR")], 1)
+    assert tto.newlinestr == "\r"
+
+
+def test_ttx_options_class_flag_newline_crlf():
+    tto = ttx.Options([("--newline", "CRLF")], 1)
+    assert tto.newlinestr == "\r\n"
+
+
+def test_ttx_options_class_flag_newline_invalid():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("--newline", "BOGUS")], 1)
+
+
+def test_ttx_options_class_flag_recalc_timestamp():
+    tto = ttx.Options([("--recalc-timestamp", "")], 1)
+    assert tto.recalcTimestamp is True
+
+
+def test_ttx_options_class_flag_flavor():
+    tto = ttx.Options([("--flavor", "woff")], 1)
+    assert tto.flavor == "woff"
+
+
+def test_ttx_options_class_flag_with_zopfli():
+    tto = ttx.Options([("--with-zopfli", ""), ("--flavor", "woff")], 1)
+    assert tto.useZopfli is True
+
+
+def test_ttx_options_class_flag_with_zopfli_fails_without_woff_flavor():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("--with-zopfli", "")], 1)
+
+
+def test_ttx_options_class_flag_quiet_and_verbose_shouldfail():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-q", ""), ("-v", "")], 1)
+
+
+def test_ttx_options_class_flag_mergefile_and_flavor_shouldfail():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-m", "testfont.ttf"), ("--flavor", "woff")], 1)
+
+
+def test_ttx_options_class_flag_onlytables_and_skiptables_shouldfail():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-t", "CFF"), ("-x", "CFF2")], 1)
+
+
+def test_ttx_options_class_flag_mergefile_and_multiplefiles_shouldfail():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("-m", "testfont.ttf")], 2)
+
+
+def test_ttx_options_class_flag_woff2_and_zopfli_shouldfail():
+    with pytest.raises(getopt.GetoptError):
+        ttx.Options([("--with-zopfli", ""), ("--flavor", "woff2")], 1)
+
+# ----------------------------
+# ttx.ttCompile function tests
+# ----------------------------
+
+
+def test_ttx_ttcompile_otf_compile_default(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestOTF.ttx")
+    outotf = os.path.join(str(tmpdir), "TestOTF.otf")
+    default_options = ttx.Options([("", "")], 1)
+    ttx.ttCompile(inttx, outotf, default_options)
+    # confirm that font was built
+    assert os.path.isfile(outotf) is True
+    # confirm that it is valid OTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outotf)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_otf_to_woff_without_zopfli(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestOTF.ttx")
+    outwoff = os.path.join(str(tmpdir), "TestOTF.woff")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff"
+    ttx.ttCompile(inttx, outwoff, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_otf_to_woff_with_zopfli(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestOTF.ttx")
+    outwoff = os.path.join(str(tmpdir), "TestOTF.woff")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff"
+    options.useZopfli = True
+    ttx.ttCompile(inttx, outwoff, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_otf_to_woff2(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestOTF.ttx")
+    outwoff2 = os.path.join(str(tmpdir), "TestTTF.woff2")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff2"
+    ttx.ttCompile(inttx, outwoff2, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff2) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff2)
+    # DSIG should not be included from original ttx as per woff2 spec (https://dev.w3.org/webfonts/WOFF2/spec/)
+    assert "DSIG" not in ttf
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_ttf_compile_default(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outttf = os.path.join(str(tmpdir), "TestTTF.ttf")
+    default_options = ttx.Options([("", "")], 1)
+    ttx.ttCompile(inttx, outttf, default_options)
+    # confirm that font was built
+    assert os.path.isfile(outttf) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outttf)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_ttf_to_woff_without_zopfli(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outwoff = os.path.join(str(tmpdir), "TestTTF.woff")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff"
+    ttx.ttCompile(inttx, outwoff, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_ttf_to_woff_with_zopfli(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outwoff = os.path.join(str(tmpdir), "TestTTF.woff")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff"
+    options.useZopfli = True
+    ttx.ttCompile(inttx, outwoff, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff)
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp", "DSIG")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_ttf_to_woff2(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outwoff2 = os.path.join(str(tmpdir), "TestTTF.woff2")
+    options = ttx.Options([("", "")], 1)
+    options.flavor = "woff2"
+    ttx.ttCompile(inttx, outwoff2, options)
+    # confirm that font was built
+    assert os.path.isfile(outwoff2) is True
+    # confirm that it is valid TTF file, can instantiate a TTFont, has expected OpenType tables
+    ttf = TTFont(outwoff2)
+    # DSIG should not be included from original ttx as per woff2 spec (https://dev.w3.org/webfonts/WOFF2/spec/)
+    assert "DSIG" not in ttf
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp")
+    for table in expected_tables:
+        assert table in ttf
+
+
+def test_ttx_ttcompile_ttf_timestamp_calcs(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outttf1 = os.path.join(str(tmpdir), "TestTTF1.ttf")
+    outttf2 = os.path.join(str(tmpdir), "TestTTF2.ttf")
+    options = ttx.Options([("", "")], 1)
+    # build with default options = do not recalculate timestamp
+    ttx.ttCompile(inttx, outttf1, options)
+    # confirm that font was built
+    assert os.path.isfile(outttf1) is True
+    # confirm that timestamp is same as modified time on ttx file
+    mtime = os.path.getmtime(inttx)
+    epochtime = timestampSinceEpoch(mtime)
+    ttf = TTFont(outttf1)
+    assert ttf['head'].modified == epochtime
+
+    # reset options to recalculate the timestamp and compile new font
+    options.recalcTimestamp = True
+    ttx.ttCompile(inttx, outttf2, options)
+    # confirm that font was built
+    assert os.path.isfile(outttf2) is True
+    # confirm that timestamp is more recent than modified time on ttx file
+    mtime = os.path.getmtime(inttx)
+    epochtime = timestampSinceEpoch(mtime)
+    ttf = TTFont(outttf2)
+    assert ttf['head'].modified > epochtime
+
+
+def test_ttx_ttcompile_otf_timestamp_calcs(tmpdir):
+    inttx = os.path.join("Tests", "ttx", "data", "TestOTF.ttx")
+    outotf1 = os.path.join(str(tmpdir), "TestOTF1.ttf")
+    outotf2 = os.path.join(str(tmpdir), "TestOTF2.ttf")
+    options = ttx.Options([("", "")], 1)
+    # build with default options = do not recalculate timestamp
+    ttx.ttCompile(inttx, outotf1, options)
+    # confirm that font was built
+    assert os.path.isfile(outotf1) is True
+    # confirm that timestamp is same as modified time on ttx file
+    mtime = os.path.getmtime(inttx)
+    epochtime = timestampSinceEpoch(mtime)
+    ttf = TTFont(outotf1)
+    assert ttf['head'].modified == epochtime
+
+    # reset options to recalculate the timestamp and compile new font
+    options.recalcTimestamp = True
+    ttx.ttCompile(inttx, outotf2, options)
+    # confirm that font was built
+    assert os.path.isfile(outotf2) is True
+    # confirm that timestamp is more recent than modified time on ttx file
+    mtime = os.path.getmtime(inttx)
+    epochtime = timestampSinceEpoch(mtime)
+    ttf = TTFont(outotf2)
+    assert ttf['head'].modified > epochtime
+
+
+# -------------------------
+# ttx.ttList function tests
+# -------------------------
+
+def test_ttx_ttlist_ttf(capsys, tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttf")
+    fakeoutpath = os.path.join(str(tmpdir), "TestTTF.ttx")
+    options = ttx.Options([("", "")], 1)
+    options.listTables = True
+    ttx.ttList(inpath, fakeoutpath, options)
+    out, err = capsys.readouterr()
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp", "DSIG")
+    # confirm that expected tables are printed to stdout
+    for table in expected_tables:
+        assert table in out
+    # test for one of the expected tag/checksum/length/offset strings
+    assert "OS/2  0x67230FF8        96       376" in out
+
+
+def test_ttx_ttlist_otf(capsys, tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestOTF.Otf")
+    fakeoutpath = os.path.join(str(tmpdir), "TestOTF.ttx")
+    options = ttx.Options([("", "")], 1)
+    options.listTables = True
+    ttx.ttList(inpath, fakeoutpath, options)
+    out, err = capsys.readouterr()
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx", "DSIG")
+    # confirm that expected tables are printed to stdout
+    for table in expected_tables:
+        assert table in out
+    # test for one of the expected tag/checksum/length/offset strings
+    assert "OS/2  0x67230FF8        96       272" in out
+
+
+def test_ttx_ttlist_woff(capsys, tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestWOFF.woff")
+    fakeoutpath = os.path.join(str(tmpdir), "TestWOFF.ttx")
+    options = ttx.Options([("", "")], 1)
+    options.listTables = True
+    options.flavor = "woff"
+    ttx.ttList(inpath, fakeoutpath, options)
+    out, err = capsys.readouterr()
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "post", "CFF ", "hmtx", "DSIG")
+    # confirm that expected tables are printed to stdout
+    for table in expected_tables:
+        assert table in out
+    # test for one of the expected tag/checksum/length/offset strings
+    assert "OS/2  0x67230FF8        84       340" in out
+
+
+def test_ttx_ttlist_woff2(capsys, tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestWOFF2.woff2")
+    fakeoutpath = os.path.join(str(tmpdir), "TestWOFF2.ttx")
+    options = ttx.Options([("", "")], 1)
+    options.listTables = True
+    options.flavor = "woff2"
+    ttx.ttList(inpath, fakeoutpath, options)
+    out, err = capsys.readouterr()
+    expected_tables = ("head", "hhea", "maxp", "OS/2", "name", "cmap", "hmtx", "fpgm", "prep", "cvt ", "loca", "glyf", "post", "gasp")
+    # confirm that expected tables are printed to stdout
+    for table in expected_tables:
+        assert table in out
+    # test for one of the expected tag/checksum/length/offset strings
+    assert "OS/2  0x67230FF8        96         0" in out
+
+# -------------------
+# main function tests
+# -------------------
+
+
+def test_ttx_main_default_ttf_dump_to_ttx(tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttf")
+    outpath = os.path.join(str(tmpdir), "TestTTF.ttx")
+    args = ["-o", outpath, inpath]
+    ttx.main(args)
+    assert os.path.isfile(outpath)
+
+
+def test_ttx_main_default_ttx_compile_to_ttf(tmpdir):
+    inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+    outpath = os.path.join(str(tmpdir), "TestTTF.ttf")
+    args = ["-o", outpath, inpath]
+    ttx.main(args)
+    assert os.path.isfile(outpath)
+
+
+def test_ttx_main_getopterror_missing_directory():
+    with pytest.raises(SystemExit):
+        with pytest.raises(getopt.GetoptError):
+            inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttf")
+            args = ["-d", "bogusdir", inpath]
+            ttx.main(args)
+
+
+def test_ttx_main_keyboard_interrupt(tmpdir, monkeypatch, capsys):
+    with pytest.raises(SystemExit):
+        inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+        outpath = os.path.join(str(tmpdir), "TestTTF.ttf")
+        args = ["-o", outpath, inpath]
+        monkeypatch.setattr(ttx, 'process', (lambda x, y: raise_exception(KeyboardInterrupt)))
+        ttx.main(args)
+
+    out, err = capsys.readouterr()
+    assert "(Cancelled.)" in err
+
+
+def test_ttx_main_system_exit(tmpdir, monkeypatch):
+    with pytest.raises(SystemExit):
+        inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+        outpath = os.path.join(str(tmpdir), "TestTTF.ttf")
+        args = ["-o", outpath, inpath]
+        monkeypatch.setattr(ttx, 'process', (lambda x, y: raise_exception(SystemExit)))
+        ttx.main(args)
+
+
+def test_ttx_main_ttlib_error(tmpdir, monkeypatch, capsys):
+    with pytest.raises(SystemExit):
+        inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+        outpath = os.path.join(str(tmpdir), "TestTTF.ttf")
+        args = ["-o", outpath, inpath]
+        monkeypatch.setattr(ttx, 'process', (lambda x, y: raise_exception(TTLibError("Test error"))))
+        ttx.main(args)
+
+    out, err = capsys.readouterr()
+    assert "Test error" in err
+
+
+def test_ttx_main_base_exception(tmpdir, monkeypatch, capsys):
+    with pytest.raises(SystemExit):
+        inpath = os.path.join("Tests", "ttx", "data", "TestTTF.ttx")
+        outpath = os.path.join(str(tmpdir), "TestTTF.ttf")
+        args = ["-o", outpath, inpath]
+        monkeypatch.setattr(ttx, 'process', (lambda x, y: raise_exception(Exception("Test error"))))
+        ttx.main(args)
+
+    out, err = capsys.readouterr()
+    assert "Unhandled exception has occurred" in err
+
+# ---------------------------
+# support functions for tests
+# ---------------------------
+
+
+def raise_exception(exception):
+    raise exception
+
+
+