Add an extra oid test to verify control characters aren't read

We only want hex digits to be read, any other character in the 8-bit
character set is invalid within an id string.

Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

tests/t0000-oid.c

@@ -11,6 +11,43 @@ BEGIN_TEST(invalid_string_moo)
 	must_fail(git_oid_mkstr(&out, "moo"));
 END_TEST
 
+static int from_hex(unsigned char i)
+{
+	if (i >= '0' && i <= '9')
+		return i - '0';
+	if (i >= 'a' && i <= 'f')
+		return 10 + (i - 'a');
+	if (i >= 'A' && i <= 'F')
+		return 10 + (i - 'A');
+	return -1;
+}
+
+BEGIN_TEST(invalid_string_all_chars)
+	git_oid out;
+	unsigned char exp[] = {
+		0x16, 0xa6, 0x77, 0x70, 0xb7,
+		0xd8, 0xd7, 0x23, 0x17, 0xc4,
+		0xb7, 0x75, 0x21, 0x3c, 0x23,
+		0xa8, 0xbd, 0x74, 0xf5, 0xe0,
+	};
+	char in[41] = "16a67770b7d8d72317c4b775213c23a8bd74f5e0\0";
+	unsigned int i;
+
+	for (i = 0; i < 256; i++) {
+		in[38] = (char)i;
+
+		if (from_hex(i) >= 0) {
+			exp[19] = (from_hex(i) << 4);
+			if (git_oid_mkstr(&out, in))
+				test_die("line %d: must accept '%s'", __LINE__, in);
+			if (memcmp(out.id, exp, sizeof(out.id)))
+				test_die("line %d: bad parse of '%s', %x != %x",
+				         __LINE__, in, exp[19], out.id[19]);
+		} else if (!git_oid_mkstr(&out, in))
+			test_die("line %d: must not accept '%s'", __LINE__, in);
+	}
+END_TEST
+
 BEGIN_TEST(invalid_string_16a67770b7d8d72317c4b775213c23a8bd74f5ez)
 	git_oid out;
 	must_fail(git_oid_mkstr(&out, "16a67770b7d8d72317c4b775213c23a8bd74f5ez"));