test(delimiter): split and delimiter view

using comparison macro for tests referencing string views
move all local code related to unity to a separate object

code/test/unit/unity/unity_extra.cpp

@@ -0,0 +1,24 @@
+#include <unity.h>
+
+#include <espurna/types.h>
+#include <espurna/libs/Delimiter.h>
+
+void test_assert_equal_string_view(espurna::StringView expected, espurna::StringView actual, unsigned int line, const char* msg) {
+    UNITY_TEST_ASSERT_EQUAL_INT(expected.length(), actual.length(), line, msg);
+    if (msg != nullptr) {
+        UNITY_TEST_ASSERT_EQUAL_CHAR_ARRAY(
+            expected.data(), actual.data(), actual.length(), line, msg);
+    } else {
+        String out;
+
+        out += "'";
+        out += expected;
+
+        out += "' vs. '";
+        out += actual;
+        out += "'";
+
+        UNITY_TEST_ASSERT_EQUAL_CHAR_ARRAY(
+            expected.data(), actual.data(), actual.length(), line, out.c_str());
+    }
+}