4 files changed, 41 insertions, 2 deletions
diff --git a/src/common.h b/src/common.h
index 93da70b..35f9b0e 100644
--- a/src/common.h
+++ b/src/common.h
@@ -1,18 +1,36 @@
 #pragma once
 
+#include <iostream>
 #include <stdlib.h>
 #include <utility>
 
 struct line_view {
   const char* line;
   size_t length;
+
+  friend std::ostream& operator<<(std::ostream& o, const line_view& lv) {
+    for (size_t i = 0; i < lv.length; i++) {
+      o << lv.line[i];
+    }
+    return o;
+  }
+
+  bool operator==(const char* l) const noexcept {
+    size_t i = 0;
+    while (i < this->length) {
+      if (l[i] != this->line[i]) {
+        return false;
+      }
+      i++;
+    }
+    return l[i] == '\0';
+  }
 };
 
 line_view load_file(const char*);
 line_view next_line(line_view, size_t*);
 
-template <typename F, typename... Args>
-void per_line(line_view file, F&& f, Args&&... args) {
+template <typename F, typename... Args> void per_line(line_view file, F&& f, Args&&... args) {
   size_t offset = 0;
   line_view lv;
   do {
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index 7410cdd..b91258c 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -1,5 +1,6 @@
 set(TEST_FILES
     catch_main.cpp
+    test_common.cpp
     test_2015.cpp
 )
 
diff --git a/test/test_2015.cpp b/test/test_2015.cpp
index e69de29..67e25f0 100644
--- a/test/test_2015.cpp
+++ b/test/test_2015.cpp
@@ -0,0 +1,5 @@
+#include "catch.hpp"
+
+TEST_CASE("", "[]") {
+
+}
diff --git a/test/test_common.cpp b/test/test_common.cpp
new file mode 100644
index 0000000..141398b
--- /dev/null
+++ b/test/test_common.cpp
@@ -0,0 +1,15 @@
+#include "catch.hpp"
+#include "common.h"
+
+TEST_CASE("load file", "[]") {
+  line_view file{"\n\n111\n2222\n33333\n", 17};
+  const char* lines[] = {"\n", "\n", "111\n", "2222\n", "33333\n"};
+  int i = 0;
+  per_line(
+      file,
+      [&i](line_view l, const char* lns[]) {
+        REQUIRE(l == lns[i++]);
+        return true;
+      },
+      lines);
+}