diff --git a/include/arduino-mock/Arduino.h b/include/arduino-mock/Arduino.h
index cbb0b7e..83b5a08 100644
--- a/include/arduino-mock/Arduino.h
+++ b/include/arduino-mock/Arduino.h
@@ -89,4 +89,43 @@ class ArduinoMock {
 ArduinoMock* arduinoMockInstance();
 void releaseArduinoMock();
 
+namespace {
+std::string ReplaceAll(std::string str, const std::string& from, const std::string& to) {
+  size_t start_pos = 0;
+  while((start_pos = str.find(from, start_pos)) != std::string::npos) {
+    str.replace(start_pos, from.length(), to);
+    start_pos += to.length(); // Handles case where 'to' is a substring of 'from'
+  }
+  return str;
+}
+}
+
+class String : public std::string {
+  public:
+    String() {}
+    String(const String& string) : String(string.c_str()) {}
+    String(const std::string& string) : std::string(string) {}
+    String(const char* string) : std::string(string) {}
+
+    String substring(int start) {
+      return substr(start);
+    }
+    String substring(int start, int end) {
+      return substr(start, end - start);
+    }
+
+    String remove(int start) {
+      return erase(start);
+    }
+
+    void replace(const String& from, const String& to) {
+      ReplaceAll(*this, from, to);
+    }
+
+    int indexOf(const char needle) {
+      return find(needle);
+    }
+};
+
+
 #endif // ARDUINO_H
diff --git a/include/arduino-mock/Serial.h b/include/arduino-mock/Serial.h
index 86d771c..82bb4f7 100644
--- a/include/arduino-mock/Serial.h
+++ b/include/arduino-mock/Serial.h
@@ -38,6 +38,8 @@ class SerialMock {
 
     MOCK_METHOD0(available, uint8_t());
     MOCK_METHOD0(read, uint8_t());
+    MOCK_METHOD1(readStringUntil, String(const char));
+    MOCK_METHOD0(peek, uint8_t());
 
     MOCK_METHOD0(flush, void());
 
@@ -79,6 +81,8 @@ class Serial_ {
 
     uint8_t available();
     uint8_t read();
+    uint8_t peek();
+    String readStringUntil(const char terminator);
 
     static void flush();
 
diff --git a/src/Serial.cc b/src/Serial.cc
index eb2d864..a56e539 100644
--- a/src/Serial.cc
+++ b/src/Serial.cc
@@ -113,5 +113,13 @@ uint8_t Serial_::read() {
   return gSerialMock->read();
 }
 
+uint8_t Serial_::peek() {
+  return gSerialMock->peek();
+}
+
+String Serial_::readStringUntil(const char term) {
+  return gSerialMock->readStringUntil(term);
+}
+
 // Preinstantiate Objects
 Serial_ Serial;