fuzz: SplitString with multiple separators

Co-authored-by: MarcoFalke <[email protected]>

Author: martinus

src/test/fuzz/string.cpp

@@ -224,7 +224,12 @@ FUZZ_TARGET(string)
         int64_t amount_out;
         (void)ParseFixedPoint(random_string_1, fuzzed_data_provider.ConsumeIntegralInRange<int>(0, 1024), &amount_out);
     }
-    (void)SplitString(random_string_1, fuzzed_data_provider.ConsumeIntegral<char>());
+    {
+        const auto single_split{SplitString(random_string_1, fuzzed_data_provider.ConsumeIntegral<char>())};
+        assert(single_split.size() >= 1);
+        const auto any_split{SplitString(random_string_1, random_string_2)};
+        assert(any_split.size() >= 1);
+    }
     {
         (void)Untranslated(random_string_1);
         const bilingual_str bs1{random_string_1, random_string_2};