diff --git a/.github/workflows/c-cpp.yml b/.github/workflows/c-cpp.yml
index 2f9e96c..3c64889 100644
--- a/.github/workflows/c-cpp.yml
+++ b/.github/workflows/c-cpp.yml
@@ -17,7 +17,9 @@ jobs:
       run: |
         sudo apt update
         sudo apt install -y g++ catch2 libmd4c-dev libmd4c-html0-dev libtomlplusplus-dev
-    - name: make
-      run: make -C src
-    - name: make check
-      run: make check -C src
+    - name: make all
+      run: make all
+    - name: make test
+      run: make test
+    - name: make clean
+      run: make clean
diff --git a/.gitignore b/.gitignore
index c528bab..3b73a2c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,4 +3,5 @@ posts/
 src/build/
 /src/blog
 /src/tests
+/src/.cache/
 *.o
diff --git a/src/config/config.cpp b/src/config/config.cpp
index 4deede6..37b7c6e 100644
--- a/src/config/config.cpp
+++ b/src/config/config.cpp
@@ -5,10 +5,10 @@
 #include <toml++/impl/parser.hpp>
 #include <toml++/toml.hpp>
 
-Config get_config(const std::string &CONFIG_FILE) {
+Config get_config(const std::string &CONFIGURATION) {
   toml::table toml_table;
   try {
-    toml_table = toml::parse_file(CONFIG_FILE);
+    toml_table = toml::parse(CONFIGURATION);
   } catch (const toml::parse_error &err) {
     std::cerr << "Parsing failed:" << std::endl << err << std::endl;
   }
diff --git a/src/config/config.hpp b/src/config/config.hpp
index 30e25ee..1c40f89 100644
--- a/src/config/config.hpp
+++ b/src/config/config.hpp
@@ -17,4 +17,7 @@ struct Config {
   General general;
 };
 
-Config get_config(const std::string &CONFIG_FILE);
+// @brief Load config into `Config` struct
+// @param CONFIGURATION content of `.toml` file containing configuration
+// @return Config with parsed configuration
+Config get_config(const std::string &CONFIGURATION);
diff --git a/src/format/format.cpp b/src/format/format.cpp
index 5bf4f23..68516de 100644
--- a/src/format/format.cpp
+++ b/src/format/format.cpp
@@ -1,6 +1,4 @@
 #include "markdown/markdown.hpp"
-#include <fstream>
-#include <sstream>
 #include <string>
 
 static bool replace_once(std::string &str, const std::string &from,
@@ -11,20 +9,3 @@ static bool replace_once(std::string &str, const std::string &from,
   str.replace(start_pos, from.length(), to);
   return true;
 }
-
-std::string inject_html_into_template(const std::string &FILE_NAME,
-                                      const std::string &TEMPLATE,
-                                      const std::string &HTML) {
-  std::string result;
-  std::ifstream file(FILE_NAME);
-  if (!file.is_open()) {
-    return "";
-  }
-  std::ostringstream ss;
-  ss << file.rdbuf();
-  result = ss.str();
-  if (replace_once(result, TEMPLATE, HTML)) {
-    return result;
-  }
-  return "";
-}
diff --git a/src/io/io.cpp b/src/io/io.cpp
new file mode 100644
index 0000000..444c436
--- /dev/null
+++ b/src/io/io.cpp
@@ -0,0 +1,36 @@
+#include "io/io.hpp"
+#include <fstream>
+#include <sstream>
+#include <stdexcept>
+#include <string>
+
+std::string read_file(const std::string &FILE_PATH) {
+  std::ifstream file(FILE_PATH);
+  if (!file) {
+    throw std::runtime_error("Error while opening file at " + FILE_PATH);
+  }
+  std::stringstream buffer;
+  buffer << file.rdbuf();
+
+  if (file.bad()) {
+    throw std::runtime_error("Error while reading file at " + FILE_PATH);
+  }
+
+  return buffer.str();
+}
+
+void write_file(const std::string &FILE_PATH, const std::string &CONTENT) {
+  std::ofstream out(FILE_PATH);
+  if (!out) {
+    throw std::runtime_error("Error while opening file for writing at " +
+                             FILE_PATH);
+  }
+
+  out << CONTENT;
+
+  if (!out) {
+    throw std::runtime_error("Error while writing to the " + FILE_PATH);
+  }
+
+  out.close();
+}
diff --git a/src/io/io.hpp b/src/io/io.hpp
new file mode 100644
index 0000000..a43df36
--- /dev/null
+++ b/src/io/io.hpp
@@ -0,0 +1,13 @@
+#include <string>
+
+// @brief Read file from given path
+// @param FILE PATH Path to the file
+// @return File content
+// @throws std::runtime_error if any errors
+std::string read_file(const std::string &FILE_PATH);
+
+/// @brief Writes the given content into a file.
+/// @param FILE_PATH Path to the file to write.
+/// @param CONTENT Content to write into the file.
+/// @throws std::runtime_error if the file cannot be opened or written.
+void write_file(const std::string &FILE_PATH, const std::string &CONTENT);
diff --git a/src/makefile b/src/makefile
index d921679..fa8f076 100644
--- a/src/makefile
+++ b/src/makefile
@@ -8,14 +8,16 @@ BUILD_DIR = build
 SOURCES = main.cpp \
           config/config.cpp \
           format/format.cpp \
-          markdown/markdown.cpp
+          markdown/markdown.cpp \
+		  io/io.cpp
 
 OBJECTS = $(SOURCES:%.cpp=$(BUILD_DIR)/%.o)
 
 TEST_SOURCES = tests.cpp \
                config/config.cpp \
                format/format.cpp \
-               markdown/markdown.cpp
+               markdown/markdown.cpp \
+			   io/io.cpp
 
 TEST_OBJECTS = $(TEST_SOURCES:%.cpp=$(BUILD_DIR)/%.o)
 
diff --git a/src/markdown/markdown.cpp b/src/markdown/markdown.cpp
index 34bf0c5..81790c5 100644
--- a/src/markdown/markdown.cpp
+++ b/src/markdown/markdown.cpp
@@ -1,6 +1,5 @@
 #include "markdown.hpp"
 #include <ctime>
-#include <fstream>
 #include <iostream>
 #include <map>
 #include <md4c-html.h>
@@ -8,21 +7,21 @@
 #include <sstream>
 #include <toml++/toml.hpp>
 
-std::optional<Metadata> get_metadata(const std::string &FILE_PATH) {
-  std::fstream file(FILE_PATH);
+std::optional<Metadata> get_metadata(const std::string &FILE_CONTENTS) {
+  std::stringstream file_contents(FILE_CONTENTS);
   std::stringstream metadata_s;
   std::string buffer;
 
   /* if there's no ---, then no metadata in file there is */
-  if (!getline(file, buffer) || buffer != "---") {
-    std::cerr << "File " << FILE_PATH << " does not contain metadata. "
+  if (!getline(file_contents, buffer) || buffer != "---") {
+    std::clog << "File does not contain any metadata. Is this intentional?"
               << std::endl;
     return std::nullopt;
   }
 
   std::map<std::string, std::string> metadata_map;
 
-  while (getline(file, buffer)) {
+  while (getline(file_contents, buffer)) {
     if (buffer == "---") {
       break;
     }
@@ -69,15 +68,15 @@ static void html_callback(const MD_CHAR *data, MD_SIZE size, void *userdata) {
   out->append(data, size);
 }
 
-std::string get_html(const std::string &FILE_PATH) {
-  std::fstream file(FILE_PATH);
+std::string get_html(const std::string &FILE_CONTENTS) {
+  std::stringstream file_contents(FILE_CONTENTS);
   std::string buffer, file_string, out;
-  getline(file, buffer);
+  getline(file_contents, buffer);
   bool is_metadata = buffer == "---";
 
   /* skip metadata */
   if (is_metadata) {
-    while (getline(file, buffer)) {
+    while (getline(file_contents, buffer)) {
       if (buffer == "---") {
         break;
       }
@@ -86,7 +85,7 @@ std::string get_html(const std::string &FILE_PATH) {
     file_string += buffer + '\n';
   }
 
-  while (getline(file, buffer)) {
+  while (getline(file_contents, buffer)) {
     file_string += buffer + '\n';
   }
 
diff --git a/src/tests.cpp b/src/tests.cpp
index b0eb144..e13575e 100644
--- a/src/tests.cpp
+++ b/src/tests.cpp
@@ -1,5 +1,6 @@
 #include "config/config.hpp"
 #include "format/format.hpp"
+#include "io/io.hpp"
 #include "markdown/markdown.hpp"
 #include <catch2/catch_all.hpp>
 #include <catch2/catch_test_macros.hpp>
@@ -7,10 +8,88 @@
 #include <optional>
 #include <string>
 
-TEST_CASE("Checking config file read", "[config]") {
-  const std::string FILE_NAME = "test_files/config.toml";
+namespace TestFiles {
+constexpr const char *config_toml = R"([general]
+lang = "en"
+title = "Blog"
 
-  Config config = get_config(FILE_NAME);
+[contact]
+author = "author"
+email = "email@example.com"
+signal = "signal url"
+)";
+
+constexpr const char *formatter_html = R"(<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>Document</title>
+</head>
+<body>
+    {{replace_me}}
+</body>
+</html>)";
+
+constexpr const char *no_metadata_post_md = R"(# This markdown has no metadata.
+That's bad. Don't do it. It's for tests only.)";
+
+constexpr const char *post_md = R"(---
+[metadata]
+author = "joseph"
+date = 2026-01-01
+title = "Example of a blog post"
+tags = ["blog", "test", "lalilulelo"]
+---
+# This is an example post
+
+In this example we will do a couple of cool markdown things.
+
+## This is a h2 header
+*This text is written in italic!*
+### Look at this!
+**This text is BOLD!**
+
+## Hello world!
+```cpp
+#include <iostream>
+
+int main() {
+    std::cout << "Hello world!" << std::endl;
+}
+```
+This is super cool!
+
+## Time to link some random website!
+This [should be clickable](https://example.com)
+
+## Image test
+![this should show an image](./image.png)
+
+## This is an ordered list
+1. one
+2. six
+3. seven
+
+## This is an unordered one
+- six
+- nine
+- six
+- nine)";
+} // namespace TestFiles
+
+// IO tests
+TEST_CASE("Test reading a file successful") {
+  std::string result = read_file("./test_files/config.toml");
+  REQUIRE(result == TestFiles::config_toml);
+}
+
+TEST_CASE("Test reading a file that doesn't exist") {
+  REQUIRE_THROWS(read_file("this/path/doesnt/exist"));
+}
+
+TEST_CASE("Checking config file read", "[config]") {
+  Config config = get_config(TestFiles::config_toml);
 
   REQUIRE(config.contact.author == "author");
   REQUIRE(config.contact.email == "email@example.com");
@@ -20,8 +99,7 @@ TEST_CASE("Checking config file read", "[config]") {
 }
 
 TEST_CASE("get_metadata function data correctness test") {
-  const std::string FILE_NAME = "./test_files/post.md";
-  Metadata result = get_metadata(FILE_NAME).value();
+  Metadata result = get_metadata(TestFiles::post_md).value();
 
   std::string expected_author = "joseph";
   struct tm datetime = {0};
@@ -41,14 +119,13 @@ TEST_CASE("get_metadata function data correctness test") {
 }
 
 TEST_CASE("get_metadata function test with a file that doesn't have metadata") {
-  const std::string FILE_NAME = ".test_files/no_metadata_post.md";
-  std::optional<Metadata> result = get_metadata(FILE_NAME);
+  std::optional<Metadata> result = get_metadata(TestFiles::no_metadata_post_md);
   REQUIRE(result == std::nullopt);
 }
 
 TEST_CASE("get_html function parsing test") {
-  const std::string INPUT = "./test_files/post.md";
-  const std::string EXPECTED_OUTPUT = R"HTML(<h1>This is an example post</h1>
+  const std::string EXPECTED_OUTPUT =
+      R"HTML(<h1>This is an example post</h1>
 <p>In this example we will do a couple of cool markdown things.</p>
 <h2>This is a h2 header</h2>
 <p><em>This text is written in italic!</em></p>
@@ -81,24 +158,5 @@ int main() {
 </ul>
 )HTML";
 
-  REQUIRE(get_html(INPUT) == EXPECTED_OUTPUT);
-}
-
-TEST_CASE("formatter injection test") {
-  const std::string FILE_NAME = "./test_files/formatter.html";
-  const std::string EXPECTED_OUTPUT = R"(<!DOCTYPE html>
-<html lang="en">
-<head>
-    <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
-    <title>Document</title>
-</head>
-<body>
-    I'm replaced!
-</body>
-</html>
-)";
-  const std::string output =
-      inject_html_into_template(FILE_NAME, "{{replace_me}}", "I'm replaced!");
-  REQUIRE(EXPECTED_OUTPUT == output);
+  REQUIRE(get_html(TestFiles::post_md) == EXPECTED_OUTPUT);
 }