--- a/src/lib-mail/test-message-header-hash.c	Fri Jun 23 09:14:40 2017 +0300
+++ b/src/lib-mail/test-message-header-hash.c	Fri Jun 23 09:24:40 2017 +0300
@@ -5,49 +5,86 @@
 #include "md5.h"
 #include "message-header-hash.h"
 
-static const unsigned char test_input[] =
+static const char test_input_with_nuls[] = {
 	"\x00\x01\x02\x03\x04\x05\x06\x07\x08\x09\x0a\x0b\x0c\x0d\x0e\x0f"
 	"\x10\x11\x12\x13\x14\x15\x16\x17\x18\x19\x1a\x1b\x1c\x1d\x1e\x1f"
-	"\x20!?x??yz\x7f\x80\x90\xff-plop\xff";
-static const unsigned char test_output[] =
-	"?\t\n? !?x?yz?-plop?";
+	"\x20!?x??yz\x7f\x80\x90\xff-plop\xff"
+};
+
+static const struct {
+	const char *input;
+	unsigned int version;
+	const char *output;
+} tests[] = {
+	{ "???hi???", 1, "???hi???" },
 
-static void test_dsync_mail_hash_more(void)
+	{ test_input_with_nuls, 2, "?\t\n? !?x?yz?-plop?" },
+	{ "?hi?", 2, "?hi?" },
+	{ "\x01hi\x01", 2, "?hi?" },
+	{ "???hi???", 2, "?hi?" },
+	{ "\x01?hi??\x01", 2, "?hi?" },
+	{ "?\t?hi?\t?", 2, "?\t?hi?\t?" },
+	{ "\n\nhi\n\n", 2, "\n\nhi\n\n" },
+};
+
+static void test_message_header_hash_more(void)
 {
 	struct message_header_hash_context ctx;
 	struct md5_context md5_ctx;
 	unsigned char md5_input[MD5_RESULTLEN], md5_output[MD5_RESULTLEN];
 
-	test_begin("dsync_mail_hash_more v2");
-	md5_init(&md5_ctx);
-	i_zero(&ctx);
-	message_header_hash_more(&ctx, &hash_method_md5, &md5_ctx, 2,
-				 test_input, sizeof(test_input)-1);
-	md5_final(&md5_ctx, md5_input);
+	test_begin("message_header_hash_more");
+	for (unsigned int i = 0; i < N_ELEMENTS(tests); i++) {
+		size_t input_len = tests[i].input == test_input_with_nuls ?
+			sizeof(test_input_with_nuls)-1 : strlen(tests[i].input);
+		md5_init(&md5_ctx);
+		i_zero(&ctx);
+		message_header_hash_more(&ctx, &hash_method_md5, &md5_ctx,
+					 tests[i].version,
+					 (const unsigned char *)tests[i].input,
+					 input_len);
+		md5_final(&md5_ctx, md5_input);
 
-	md5_init(&md5_ctx);
-	md5_update(&md5_ctx, test_output, sizeof(test_output)-1);
-	md5_final(&md5_ctx, md5_output);
+		md5_init(&md5_ctx);
+		md5_update(&md5_ctx, tests[i].output, strlen(tests[i].output));
+		md5_final(&md5_ctx, md5_output);
+
+		test_assert_idx(memcmp(md5_input, md5_output, MD5_RESULTLEN) == 0, i);
 
-	test_assert(memcmp(md5_input, md5_output, MD5_RESULTLEN) == 0);
+		/* single byte at a time */
+		md5_init(&md5_ctx);
+		i_zero(&ctx);
+		for (unsigned int j = 0; j < input_len; j++) {
+			unsigned char chr = tests[i].input[j];
+			message_header_hash_more(&ctx, &hash_method_md5,
+						 &md5_ctx, tests[i].version,
+						 &chr, 1);
+		}
+		md5_final(&md5_ctx, md5_input);
+		test_assert_idx(memcmp(md5_input, md5_output, MD5_RESULTLEN) == 0, i);
 
-	/* single byte at a time */
-	md5_init(&md5_ctx);
-	i_zero(&ctx);
-	for (unsigned int i = 0; i < sizeof(test_input)-1; i++) {
-		message_header_hash_more(&ctx, &hash_method_md5, &md5_ctx, 2,
-					 test_input + i, 1);
+		/* random number of chars at a time */
+		md5_init(&md5_ctx);
+		i_zero(&ctx);
+		for (unsigned int j = 0; j < input_len; ) {
+			const unsigned char *input_part =
+				(const unsigned char *)tests[i].input + j;
+			unsigned int len = rand() % (input_len - j) + 1;
+			message_header_hash_more(&ctx, &hash_method_md5,
+						 &md5_ctx, tests[i].version,
+						 input_part, len);
+			j += len;
+		}
+		md5_final(&md5_ctx, md5_input);
+		test_assert_idx(memcmp(md5_input, md5_output, MD5_RESULTLEN) == 0, i);
 	}
-	md5_final(&md5_ctx, md5_input);
-	test_assert(memcmp(md5_input, md5_output, MD5_RESULTLEN) == 0);
-
 	test_end();
 }
 
 int main(void)
 {
 	static void (*test_functions[])(void) = {
-		test_dsync_mail_hash_more,
+		test_message_header_hash_more,
 		NULL
 	};
 	return test_run(test_functions);