diff --git a/Makefile.am b/Makefile.am
index f0cc385..948b50d 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -21,12 +21,26 @@ dist-hook:
 	cp -p $(PSL_TESTFILE) $(distdir)/list/tests
 
 clean-local:
-	rm -rf */*.gc?? libpsl.info lcov
+	rm -rf */*.gc?? */*/*.gc?? libpsl.info lcov
 
 check-coverage:
-	$(MAKE) clean
-	lcov --no-external --capture --initial --directory . --output-file libpsl.info
-	CFLAGS=$$CFLAGS" --coverage" LDFLAGS=$$LDFLAGS" --coverage" ./configure && $(MAKE) check
-	lcov --no-external --capture --directory . --output-file libpsl.info
-# lcov --remove libpsl.info 'tests/*.c' 'src/lookup_*' 'src/psl2c.c' -o libpsl.info
+	if test -z "$(XLIB)"; then \
+		CFLAGS=$$CFLAGS" --coverage -O0" LDFLAGS=$$LDFLAGS" --coverage" ./configure --disable-runtime --disable-builtin; \
+	else \
+		CFLAGS=$$CFLAGS" --coverage -O0" LDFLAGS=$$LDFLAGS" --coverage" ./configure --enable-runtime=$(XLIB) --enable-builtin=$(XLIB); \
+	fi
+	$(MAKE) clean && $(MAKE)
+	lcov --no-external --capture --initial --directory src --output-file libpsl.info
+	$(MAKE) check
+	lcov --no-external --capture --directory src --output-file libpsl.info
+	lcov --remove libpsl.info 'src/psl2c.c' -o libpsl.info
 	genhtml --prefix . --ignore-errors source libpsl.info --legend --title "libpsl" --output-directory=lcov
+
+check-coverage-libidn:
+	XLIB=libidn $(MAKE) check-coverage
+
+check-coverage-libidn2:
+	XLIB=libidn2 $(MAKE) check-coverage
+
+check-coverage-libicu:
+	XLIB=libicu $(MAKE) check-coverage
diff --git a/src/psl.c b/src/psl.c
index e829dcf..4add23e 100644
--- a/src/psl.c
+++ b/src/psl.c
@@ -1728,7 +1728,7 @@ out:
 			if ((tmp = u8_tolower((uint8_t *)str, len, 0, UNINORM_NFKC, NULL, &len))) {
 				ret = PSL_SUCCESS;
 				if (lower) {
-					*lower = tmp;
+					*lower = (char*)tmp;
 					tmp = NULL;
 				} else
 					free(tmp);
diff --git a/tests/Makefile.am b/tests/Makefile.am
index c71cd99..d3e9667 100644
--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -23,3 +23,12 @@ check_PROGRAMS = $(PSL_TESTS)
 
 TESTS_ENVIRONMENT = TESTS_VALGRIND="@VALGRIND_ENVIRONMENT@"
 TESTS = $(PSL_TESTS)
+
+# dafsa.psl must be created before any test is executed
+# check-local target works in parallel to the tests, so the test suite will likely fail
+BUILT_SOURCES = dafsa.psl
+dafsa.psl:
+	$(top_srcdir)/src/psl-make-dafsa --input-format=psl --output-format=binary "$(PSL_FILE)" psl.dafsa
+
+clean-local:
+	rm -f psl.dafsa
\ No newline at end of file
diff --git a/tests/test-is-cookie-domain-acceptable.c b/tests/test-is-cookie-domain-acceptable.c
index c50342d..6bac1a4 100644
--- a/tests/test-is-cookie-domain-acceptable.c
+++ b/tests/test-is-cookie-domain-acceptable.c
@@ -65,6 +65,7 @@ static void test_psl(void)
 		{ "www.his.name", "his.name", 1 },
 		{ "www.his.name", "name", 0 },
 		{ "www.example.com", "www.example.com", 1 },
+		{ "www.example.com", "wwww.example.com", 0 },
 		{ "www.example.com", "example.com", 1 },
 		{ "www.example.com", "com", 0 }, /* not accepted by normalization (PSL rule 'com') */
 		{ "www.example.com", "example.org", 0 },
@@ -77,6 +78,8 @@ static void test_psl(void)
 		{ "2a00:1450:4013:c01::8b", ":1450:4013:c01::8b", 0 }, /* IPv6 address, partial match */
 		{ "::ffff:192.1.123.2", "::ffff:192.1.123.2", 1 }, /* IPv6 address dotted-quad, full match */
 		{ "::ffff:192.1.123.2", ".1.123.2", 0 }, /* IPv6 address dotted-quad, partial match */
+		{ NULL, ".1.123.2", 0 },
+		{ "hiho", NULL, 0 },
 	};
 	unsigned it;
 	psl_ctx_t *psl;
@@ -98,6 +101,9 @@ static void test_psl(void)
 		}
 	}
 
+	/* do checks to cover more code paths in libpsl */
+	psl_is_cookie_domain_acceptable(NULL, "example.com", "example.com");
+
 	psl_free(psl);
 }
 
diff --git a/tests/test-is-public-all.c b/tests/test-is-public-all.c
index f4b7494..f76cfb8 100644
--- a/tests/test-is-public-all.c
+++ b/tests/test-is-public-all.c
@@ -131,7 +131,7 @@ static void test_psl_entry(const psl_ctx_t *psl, const char *domain, int type)
 static void test_psl(void)
 {
 	FILE *fp;
-	psl_ctx_t *psl;
+	psl_ctx_t *psl, *psl3;
 	const psl_ctx_t *psl2;
 	int type = 0;
 	char buf[256], *linep, *p;
@@ -142,6 +142,11 @@ static void test_psl(void)
 	psl2 = psl_builtin();
 	printf("builtin PSL has %d suffixes and %d exceptions\n", psl_suffix_count(psl2), psl_suffix_exception_count(psl2));
 
+	if (!(psl3 = psl_load_file("psl.dafsa"))) {
+		fprintf(stderr, "Failed to load 'psl.dafsa'\n");
+		failed++;
+	}
+
 	if ((fp = fopen(PSL_FILE, "r"))) {
 #ifdef HAVE_CLOCK_GETTIME
 		clock_gettime(CLOCK_REALTIME, &ts1);
@@ -174,6 +179,9 @@ static void test_psl(void)
 
 			if (psl2)
 				test_psl_entry(psl2, p, type);
+
+			if (psl3)
+				test_psl_entry(psl3, p, type);
 		}
 
 #ifdef HAVE_CLOCK_GETTIME
@@ -187,6 +195,7 @@ static void test_psl(void)
 
 	psl_free(psl);
 	psl_free((psl_ctx_t *)psl2);
+	psl_free(psl3);
 }
 
 int main(int argc, const char * const *argv)
diff --git a/tests/test-is-public.c b/tests/test-is-public.c
index 5d32425..d1567b7 100644
--- a/tests/test-is-public.c
+++ b/tests/test-is-public.c
@@ -84,6 +84,7 @@ static void test_psl(void)
 		{ "adfhoweirh", 1 }, /* unknown TLD */
 	};
 	unsigned it;
+	int result, ver;
 	psl_ctx_t *psl;
 
 	psl = psl_load_file(PSL_FILE);
@@ -92,7 +93,7 @@ static void test_psl(void)
 
 	for (it = 0; it < countof(test_data); it++) {
 		const struct test_data *t = &test_data[it];
-		int result = psl_is_public_suffix(psl, t->domain);
+		result = psl_is_public_suffix(psl, t->domain);
 
 		if (result == t->result) {
 			ok++;
@@ -102,6 +103,68 @@ static void test_psl(void)
 		}
 	}
 
+	/* do some checks to cover more code paths in libpsl */
+	psl_is_public_suffix(NULL, "xxx");
+
+	if ((ver = psl_check_version_number(0)) == 0) {
+		printf("psl_check_version_number(0) is 0\n");
+		failed++;
+	} else {
+		if (((result = psl_check_version_number(ver)) != ver)) {
+			printf("psl_check_version_number(%06X) is %06X\n", ver, result);
+			failed++;
+		}
+
+		if (((result = psl_check_version_number(ver - 1)) != 0)) {
+			printf("psl_check_version_number(%06X) is %06X\n", ver - 1, result);
+			failed++;
+		}
+
+		if (((result = psl_check_version_number(ver + 1)) != ver)) {
+			printf("psl_check_version_number(%06X) is %06X\n", ver, result);
+			failed++;
+		}
+	}
+
+	psl_str_to_utf8lower("www.example.com", "utf-8", "en", NULL);
+	psl_str_to_utf8lower(NULL, "utf-8", "en", NULL);
+
+	{
+		char *lower = NULL;
+
+		psl_str_to_utf8lower("www.example.com", NULL, "de", &lower);
+		free(lower); lower = NULL;
+
+		psl_str_to_utf8lower("\374bel.de", NULL, "de", &lower);
+		free(lower); lower = NULL;
+
+		psl_str_to_utf8lower("\374bel.de", "iso-8859-1", NULL, &lower);
+		free(lower); lower = NULL;
+
+		psl_str_to_utf8lower(NULL, "utf-8", "en", &lower);
+		free(lower); lower = NULL;
+	}
+
+	psl_get_version();
+	psl_builtin_filename();
+	psl_builtin_outdated();
+	psl_builtin_file_time();
+	psl_builtin_sha1sum();
+	psl_suffix_wildcard_count(NULL);
+	psl_suffix_wildcard_count(psl);
+	psl_suffix_wildcard_count(psl_builtin());
+	psl_suffix_count(NULL);
+	psl_suffix_exception_count(NULL);
+	psl_load_file(NULL);
+	psl_load_fp(NULL);
+	psl_registrable_domain(NULL, "");
+	psl_registrable_domain(psl, NULL);
+	psl_registrable_domain(psl, "www.example.com");
+	psl_unregistrable_domain(NULL, "");
+	psl_unregistrable_domain(psl, NULL);
+	psl_is_public_suffix2(NULL, "", PSL_TYPE_ANY);
+	psl_is_public_suffix2(psl, NULL, PSL_TYPE_ANY);
+
 	psl_free(psl);
 }