[gparted] Add test that PipeCapture can read NUL byte in middle of UTF-8 char (#777973)

[Curtis Gedak <gedakc src gnome org>]

commit 6b82616d2e5dfddea8b73cc65d64bfc7e08d8388
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Thu May 25 11:38:43 2017 +0100

    Add test that PipeCapture can read NUL byte in middle of UTF-8 char (#777973)
    
    Test that binary data that happens to be the start of a multi-byte UTF-8
    character but then contains a NUL byte is successfully read.  The test
    currently detects failure thus:
    
        $ ./test_PipeCapture
        ...
        [ RUN      ] PipeCaptureTest.ReadNULByteInMiddleOfMultiByteUTF8Character
        test_PipeCapture.cc:346: Failure
              Expected: expectedstr
             Of length: 7
        To be equal to: capturedstr.raw()
             Of length: 0
        With first binary difference:
        < 0x00000000  "._45678"           00 5F 34 35 36 37 38
        --
        > 0x00000000  ""
        [  FAILED  ] PipeCaptureTest.ReadNULByteInMiddleOfMultiByteUTF8Character (0 ms)
        ...
    
    Bug 777973 - Segmentation fault on bad disk

 tests/test_PipeCapture.cc |   17 +++++++++++++++++
 1 files changed, 17 insertions(+), 0 deletions(-)
---
diff --git a/tests/test_PipeCapture.cc b/tests/test_PipeCapture.cc
index a45804b..608d171 100644
--- a/tests/test_PipeCapture.cc
+++ b/tests/test_PipeCapture.cc
@@ -337,6 +337,23 @@ TEST_F( PipeCaptureTest, ReadEmbeddedNULCharacter )
        EXPECT_TRUE( eof_signalled );
 }
 
+TEST_F( PipeCaptureTest, ReadNULByteInMiddleOfMultiByteUTF8Character )
+{
+       // Test NUL byte in the middle of reading a multi-byte UTF-8 character.
+       const char * buf = "\xC0\x00_45678";
+       inputstr = std::string( buf, 8 );
+       PipeCapture pc( pipefds[ReaderFD], capturedstr );
+       pc.signal_eof.connect( sigc::mem_fun( *this, &PipeCaptureTest::eof_callback ) );
+       pc.connect_signal();
+       run_writer_thread();
+       // Initial \xC0 byte is part of an incomplete UTF-8 characters so will be skipped
+       // by PipeCapture.
+       buf = "\x00_45678";
+       expectedstr = std::string( buf, 7 );
+       EXPECT_BINARYSTRINGEQ( expectedstr, capturedstr.raw() );
+       EXPECT_TRUE( eof_signalled );
+}
+
 }  // namespace GParted
 
 // Custom Google Test main() which also initialises the Glib threading system for