lib/file: Implement writeByte function

src/lib/file.cpp

@@ -129,6 +129,22 @@ ErrorOr<tiny_utf8::string> File::readString(uint64_t bytes){
     return ErrorOr<tiny_utf8::string>(tiny_utf8::string(s));
 }
 
+ErrorOrVoid File::writeByte(uint8_t byte){
+
+    bool failure = false;
+
+    try{
+
+        this->fileStream.seekg(this->cursorPosition);
+        this->fileStream << byte;
+        this->cursorPosition++;
+    }catch(std::exception& e){
+        failure = true;
+    }
+
+    return failure ? ErrorOrVoid(true, ErrorCodes::UNKNOWN) : ErrorOrVoid();
+}
+
 ErrorOr<File*> File::open(std::string path, char mode, uint64_t startPosition){
     if (!std::filesystem::exists(path)) {
         return ErrorOr<File*>(true, ErrorCodes::FILE_NOT_FOUND, nullptr);

src/test/file.cpp

@@ -38,5 +38,21 @@ int main(){
 
     //readString test
     tiny_utf8::string data = file->readString(5).value;
-    std::cout << data << std::endl;
+    ASSERT(data == "tring");
+    std::cout << "Passed read string test." << std::endl;
+    file->close();
+    delete file;
+
+    //Write Tests
+    File *writeFile;
+    File *readFile;
+
+    writeFile = File::open("resources/unicode_data/writeTest", 'w').value;
+    writeFile->writeByte('a');
+    writeFile->close();
+
+    readFile = File::open("resources/unicode_data/writeTest", 'r').value;
+    uint8_t testByte = readFile->readByte().value;
+    ASSERT(testByte == 'a');
+    std::cout << "Passed write byte test." << std::endl;
 }