test: Add test for embedded null in hex string

Also, fix style in the corresponding function. The style change can be
reviewed with "--word-diff-regex=."

Author: MarcoFalke

src/test/util_tests.cpp

@@ -153,7 +153,7 @@ static const unsigned char ParseHex_expected[65] = {
     0xde, 0x5c, 0x38, 0x4d, 0xf7, 0xba, 0x0b, 0x8d, 0x57, 0x8a, 0x4c, 0x70, 0x2b, 0x6b, 0xf1, 0x1d,
     0x5f
 };
-BOOST_AUTO_TEST_CASE(util_ParseHex)
+BOOST_AUTO_TEST_CASE(parse_hex)
 {
     std::vector<unsigned char> result;
     std::vector<unsigned char> expected(ParseHex_expected, ParseHex_expected + sizeof(ParseHex_expected));
@@ -169,6 +169,14 @@ BOOST_AUTO_TEST_CASE(util_ParseHex)
     result = ParseHex(" 89 34 56 78");
     BOOST_CHECK(result.size() == 4 && result[0] == 0x89 && result[1] == 0x34 && result[2] == 0x56 && result[3] == 0x78);
 
+    // Embedded null is treated as end
+    const std::string with_embedded_null{" 11 "s
+                                         " \0 "
+                                         " 22 "s};
+    BOOST_CHECK_EQUAL(with_embedded_null.size(), 11);
+    result = ParseHex(with_embedded_null);
+    BOOST_CHECK(result.size() == 1 && result[0] == 0x11);
+
     // Stop parsing at invalid value
     result = ParseHex("1234 invalid 1234");
     BOOST_CHECK(result.size() == 2 && result[0] == 0x12 && result[1] == 0x34);

src/util/strencodings.cpp

@@ -78,7 +78,6 @@ bool IsHexNumber(std::string_view str)
 
 std::vector<unsigned char> ParseHex(std::string_view str)
 {
-    // convert hex dump to vector
     std::vector<unsigned char> vch;
     auto it = str.begin();
     while (it != str.end() && it + 1 != str.end()) {